From paul.clark at durham.ac.uk Wed Jan 3 10:35:12 2001 From: paul.clark at durham.ac.uk (Paul Clark) Date: Thu Jul 29 11:52:02 2004 Subject: CCD-world: Vishat FETs. References: <85AB8CB6EF94D211BC8400105AA28F2963FF42@MERCURY.roe.ac.uk> Message-ID: <3A52F250.F9259511@durham.ac.uk> The following was posted to CCD-world: Hi Ken, I find Flint Distribution very useful for hard-to-get surface mount components. They can normally supply small quantities but you will need to pay an inflated price. I couldn't see Siliconix on their product list but they may be able to supply a Rohm equivalent. http://www.flint.co.uk Good Luck, Paul Clark ----------------------------------------------------- EurIng Paul Clark |Email: paul.clark@durham.ac.uk University of Durham |WWW: http://aig-www.dur.ac.uk Department of Physics | Rochester Building |Office: +44 (0)191 374 2762 South Road |Lab: +44 (0)191 374 2763 Durham |Secretary: +44 (0)191 374 2678 DH1 3LE |Mobile: +44 (0)777 372 2949 UK |Fax: +44 (0)191 374 3709 ----------------------------------------------------- - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From ninkov at cis.rit.edu Thu Jan 4 04:02:53 2001 From: ninkov at cis.rit.edu (Zoran Ninkov) Date: Thu Jul 29 11:52:02 2004 Subject: CCD-world: Special Issue of Optical Engineering References: <85AB8CB6EF94D211BC8400105AA28F2963FF42@MERCURY.roe.ac.uk> <3A52F250.F9259511@durham.ac.uk> Message-ID: <3A542E2D.7CA71F93@cis.rit.edu> The following was posted to CCD-world: For all those involved with detector arrays. There will be a special issue of the peer reviewed journal Optical Engineering dedicated to focal plane array developments. We are hoping to receive a wide cross-section of papers. If you are interested please contact either of the guest editors listed below. The notice of this special issue is attached below and will also be posted on the SPIE web site at http://www.spie.org/web/journals/oe_sched.html (eventually). Thanks, Zoran ------------------------------------------------------------------- December 2001 Focal Plane Detector Array Developments Guest Editors: Zoran Ninkov Rochester Institute of Technology Center for Imaging Science 54 Lomb Memorial Drive Rochester, NY 14623-5604 716/475-7195 * 716/475-5988 FAX E-mail: ninkov@cis.rit.edu William J. Forrest University of Rochester Department of Physics and Astronomy 600 Wilson Boulevard Rochester, NY 14627-0171 716/275-4343 * 716/275-8527 FAX E-mail: forrest@pas.rochester.edu Major advances over the last ten years have been made in the performance and availability of focal plane arrays optimized to detect electromagnetic radiation in the x-ray, ultraviolet, visible, or infrared spectra. This special section seeks papers covering all aspects of the fabrication, evaluation, and use of focal plane arrays for detecting photons in any part of this energy range. Papers of an experimental and/or theoretical nature are welcome. Topics of particular interest include - CCD and CMOS arrays; - array enhancement techniques such as backside thinning, use of lenslet arrays, and fully depleted devices; - hybridized arrays such as those routinely used in the infrared; - advances in multiplexers, detector materials (e.g., InSb, HgCdTe), and hybridizing techniques; - space radiation effects on focal plane arrays; - superconducting tunnel junction devices; - quantum well devices; - integration of micro-electro-mechanical systems and - micro-opto-electro-mechanical systems with focal plane arrays. Manuscripts due March 1, 2001 -- Dr. Zoran Ninkov Center for Imaging Science Rochester Institute of Technology 54 Lomb Memorial Drive Rochester NY 14623-5604 U.S.A. Telephone : 716 - 475 7195 Fax : 716 - 475 5988 e-mail : ninkov@cis.rit.edu - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From cno at caltel.com Sat Jan 13 00:04:11 2001 From: cno at caltel.com (Michael McNeil) Date: Thu Jul 29 11:52:02 2004 Subject: CCD-world: RE:UV and the Kodak KPFo4o1E Message-ID: <3A5FFDEB.6D55396F@caltel.com> The following was posted to CCD-world: Question. Today I made a deal to get a new, not even out yet, UV LED 350 nm. My attempt is to use this as a reference for a grism spectrometer. The LED has a very tight wavelength, and may do the job for the one end of the band. Now, does anyone know if the UV going into a fiber into the top of the light path from the scope, will damage the KPF-0401E CCD chip? Mike Camanche North Observatory - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From pcm at ing.iac.es Mon Jan 15 12:15:58 2001 From: pcm at ing.iac.es (Peter Moore) Date: Thu Jul 29 11:52:02 2004 Subject: CCD-world: Damage to detectors from photon sources In-Reply-To: <3A5FFDEB.6D55396F@caltel.com> Message-ID: The following was posted to CCD-world: Good morning all (assuming the first task of the day is to read ccd-world :-) Michael's recent mail on UV damage prompts me to ask a similar question from the other end of the realm ... Would a 650nm HeNe laser beam with 2mw of power damage a HAWAII MgCdTl detector ? We would like to use interferometry to align an optical system on one of our cameras (INGRID). The prefered way is to use back reflections from the objectives inside the cryostat to align a warm foreoptic collimator. This implies that the laser beam would be imaged onto the detector. I've done some rudimentry calculations and the power load would seem frightning (in watts/cm^2) but then reasoning that it would be thermal energies that would damage the detector and, since the laser is (almost) monochromatic, very little thermal energy would reach the detector and _most_ (how much ?) of the visible would be reflected from the AR coating anyway .... Have I overlooked something important here ? Has anyone used a laser to image onto a detector before ? Would anyone like to try :-) Have a good day, Peter. =+===+===+===+===+===+===+===+===+ ING +===+===+===+===+===+===+===+= = Peter Moore, Isaac Newton Group, La Palma Observatory, Spain. = = E-mail pcm@ing.iac.es Voice Office +34 922 405566 = = S-mail Apartado de Correo 321, Fax Office +34 922 405646 = = 38780 Santa Cruz de La Palma, Voice Home +34 922 435042 = = Canary Islands, Spain. = =+===+===+===+===+===+===+===+===+ LPO +===+===+===+===+===+===+===+= - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From CMOSCCD at aol.com Thu Jan 18 03:18:03 2001 From: CMOSCCD at aol.com (CMOSCCD@aol.com) Date: Thu Jul 29 11:52:02 2004 Subject: CCD-world: UV DAMAGE Message-ID: <1e.101a2772.2797f2ab@aol.com> The following was posted to CCD-world: In a message dated 1/14/01 12:10:34 PM Pacific Standard Time, cno@caltel.com writes: << Question. Today I made a deal to get a new, not even out yet, UV LED 350 nm. My attempt is to use this as a reference for a grism spectrometer. The LED has a very tight wavelength, and may do the job for the one end of the band. Now, does anyone know if the UV going into a fiber into the top of the light path from the scope, will damage the KPF-0401E CCD chip? Mike >> **************************jj Mike, Be careful with (intense) UV light around multi-phase CCDs (two phase, three phase, four phase, etc.). Your wavelength may be long enough to not cause concern. However, at 2500 A, photoemission of electrons from the silicon into the gate oxide will occur causing charging (any photon with energy greater than 4.29 eV will do this). We damaged a few three-phase CCDs by exposing the device to an intense UV source. Because of the over-lapping poly gates. . . photoemission and negative charging of the gate oxide was not uniform. This in turn created potential pockets in the signal channel causing the CTE to degrade. Single phase sensors (virtual phase) respond differently to UV because there is only one layer of poly silicon. In fact, the SXT mission used UV flood to discharge positive charge buildup caused by ionizing radiation generated by x-rays. More discussions on radiation damage including UV light are discussed in the CCD book. Jim Janesick *******************************jj - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From cno at caltel.com Tue Jan 23 10:37:37 2001 From: cno at caltel.com (Michael McNeil) Date: Thu Jul 29 11:52:02 2004 Subject: CCD-world: UV DAMAGE References: <1e.101a2772.2797f2ab@aol.com> Message-ID: <3A6DC160.D2F440CD@caltel.com> The following was posted to CCD-world: Great, and thanks for the up date. I also heard from Gloria at Kodak from this list. The LED speced out at 375 nm so that even better. So I think I will do a master of both references, RED and UV, and save that then just merge that master to the spectra image. I'm using the new VSpec program, very nice, so its easy to bin the reference signals then the spectra line. By this I won't have to fire off the UV every time. If any one is interested in the Vspec, for windows, let me know and I'll post the URL. Val in France, that wrote it, is the one that just developed the new mammography operation program, about 100% accurate, she works at the GE think tank in Paris. One smart lady. Mike - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From tabbott at not.iac.es Thu Feb 1 10:15:52 2001 From: tabbott at not.iac.es (Tim Abbott) Date: Thu Jul 29 11:52:02 2004 Subject: CCD-world: Jupiter (fwd) Message-ID: The following was posted to CCD-world: Hey All, Jim Janesick drew my attention to this Cassini image: http://www.spacer.com/images/cassini-galileo-jupiter-io-desk-1000.jpg It is, in the vernacular, totally cool... Tim -- Tim Abbott, Astronomer-in-Charge, Nordic Optical Telescope tabbott@not.iac.es, http://www.not.iac.es/~tabbott/, +34 922 425 472 Roque de Los Muchachos & Santa Cruz de La Palma, Canary Islands, Spain - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From miranda.miller at nvl.army.mil Tue Feb 6 12:54:11 2001 From: miranda.miller at nvl.army.mil (Miller, Miranda A Ms TRW) Date: Thu Jul 29 11:52:02 2004 Subject: CCD-world: ccds responsive at 808 nm? Message-ID: The following was posted to CCD-world: I am working on building an active near-IR polarimeter. I'd like to use a solid-state sensor rather than an I^2 device, but am having trouble finding a ccd which has a quantum efficiency > 50% at 808 nm, and has camera noise less than 50-100 electrons. I'm also hoping for the ccd to be an interline transfer device with a VOD, and an array size around 2048x128, with a frame rate around 80 fps. Pointers, anyone? Thanks in advance, Miranda Miranda Miller Electro-Optics Engineer TRW Systems / Nightvision Labs mailto: miranda.miller@nvl.army.mil voice: (703) 704-2741, fax: (703) 704-1345 - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From Peter.Pool at marconi.com Tue Feb 6 20:06:51 2001 From: Peter.Pool at marconi.com (Peter.Pool@marconi.com) Date: Thu Jul 29 11:52:02 2004 Subject: CCD-world: ccds responsive at 808 nm? Message-ID: The following was posted to CCD-world: Hi Miranda, >50% QE @ 808nm is no problem for a back illuminated CCD, but I'm not aware of a 1024 x 128 that would be capable of 80fps, these devices are mostly made for slower, low noise applications. If you want it enough, we'd be pleased to design and make it for you. I think the Vertical Overflow Drains and >50% @ 808 don't go together. Devices with VOD usually have about 2?m of sensitive silicon. As I understand it, one of the uses of VOD is to kill the NIR QE in order to approach a photopic response. Peter Pool CCD Chief Engineer Marconi Applied Technologies http://www.marconitech.com/ccds/ -----Original Message----- From: MIME :miranda.miller@nvl.army.mil Sent: 06 February 2001 17:20 To: ccd-world@astro.ku.dk Subject: CCD-world: ccds responsive at 808 nm? The following was posted to CCD-world: I am working on building an active near-IR polarimeter. I'd like to use a solid-state sensor rather than an I^2 device, but am having trouble finding a ccd which has a quantum efficiency > 50% at 808 nm, and has camera noise less than 50-100 electrons. I'm also hoping for the ccd to be an interline transfer device with a VOD, and an array size around 2048x128, with a frame rate around 80 fps. Pointers, anyone? Thanks in advance, Miranda Miranda Miller Electro-Optics Engineer TRW Systems / Nightvision Labs mailto: miranda.miller@nvl.army.mil voice: (703) 704-2741, fax: (703) 704-1345 - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From thomas_g_burke at md.northgrum.com Tue Feb 6 15:26:01 2001 From: thomas_g_burke at md.northgrum.com (Burke, Thomas G.) Date: Thu Jul 29 11:52:02 2004 Subject: CCD-world: ccds responsive at 808 nm? Message-ID: <51FBD4A8EFD9D111BA7300A0C927DADB03E3EE27@xcgmd008.md.essd.northgrum.com> The following was posted to CCD-world: I imagine we could make some of those, but the price is probably prohibitive for you... > -----Original Message----- > From: Miller, Miranda A Ms TRW [SMTP:miranda.miller@nvl.army.mil] > Sent: Tuesday, February 06, 2001 11:54 AM > To: 'ccd-world@astro.ku.dk' > Subject: CCD-world: ccds responsive at 808 nm? > > The following was posted to CCD-world: > > I am working on building an active near-IR polarimeter. I'd like to use a > solid-state sensor rather than an I^2 device, but am having trouble > finding > a ccd which has a quantum efficiency > 50% at 808 nm, and has camera noise > less than 50-100 electrons. I'm also hoping for the ccd to be an > interline > transfer device with a VOD, and an array size around 2048x128, with a > frame > rate around 80 fps. > > Pointers, anyone? > Thanks in advance, > Miranda > > Miranda Miller > Electro-Optics Engineer > TRW Systems / Nightvision Labs > mailto: miranda.miller@nvl.army.mil > voice: (703) 704-2741, fax: (703) 704-1345 > > - -- CCD-world -- -- > CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk > Standard replies will go to the list; address personal replies manually. > For more information, please go to: http://www.not.iac.es/CCD-world/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From Paul.Jorden at marconi.com Wed Feb 7 10:15:34 2001 From: Paul.Jorden at marconi.com (Paul.Jorden@marconi.com) Date: Thu Jul 29 11:52:02 2004 Subject: CCD-world: ccds responsive at 808 nm? Message-ID: The following was posted to CCD-world: Hi Miranda, > -----Original Message----- > From: MIME :miranda.miller@nvl.army.mil > Sent: 06 February 2001 17:20 > To: ccd-world@astro.ku.dk > Subject: CCD-world: ccds responsive at 808 nm? > > I am working on building an active near-IR polarimeter. I'd > like to use a > solid-state sensor rather than an I^2 device, but am having > trouble finding > a ccd which has a quantum efficiency > 50% at 808 nm, and has > camera noise > less than 50-100 electrons. I'm also hoping for the ccd to > be an interline > transfer device with a VOD, and an array size around > 2048x128, with a frame rate around 80 fps. > I've been thinking about this ccd-world query. It looks feasable after a quick look. I believe Peter Pool has also responded. Here are my comments: We already make backthinned CCDs with a QE of >50%. In fact, for our standard silicon devices, at -30C operation, we expect a QE of 75%. Existing amplifier designs would yield < 50 e- noise at say 5 MHz/port readout rate. I would propose a 2k*128 split frame-transfer device, with split serial registers, having four output ports. If each port runs at 6 MHz, this should allow an 80 fps rate. The frame-transfer architecture delivers a full 100% fill factor. Such a device does not exist to my knowledge, but this is an example of the sort of custom device that we would make. For example our CCD39 is a similar architecture, with 80*80 format- and operates at ~ 1 kHz frame rate with ~5 e- noise. Scaling up to the 2k*128 device is possible. Regards, Paul J _________________________________________________________ Dr Paul Jorden, CCD Sensors, Marconi Applied Technologies Waterhouse Lane, Chelmsford, Essex, CM1 2QU, UK Tel: +44 (0)1245 453458 (direct), -493493 (switchboard) Fax: +44 (0)1245 453224 (direct), -492492 (general) http://www.marconitech.com/ccds/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From bgpark at boao.re.kr Thu Feb 8 11:54:37 2001 From: bgpark at boao.re.kr (Byeong-Gon Park) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: vibration and telescope Message-ID: <3A81FC5D.3D5C1539@boao.re.kr> Dear world astronomical society, This question is not related with CCDs directly, but I hope to get information about permitted level of ground vibration by mining industry near an astronomical observatory. Is there any law - either government law or bylaws of the observatory - which defines a quantitative guidance of distance and ground vibration or EMI due to nearby mining industry? Any related information will be appreciated. Thanks, Byeong-Gon -------------- next part -------------- A non-text attachment was scrubbed... Name: bgpark.vcf Type: text/x-vcard Size: 425 bytes Desc: Card for Byeong-Gon Park Url : http://www.ctio.noao.edu/pipermail/ccd-world/attachments/20010208/62eb582e/bgpark.vcf From thomas_g_burke at md.northgrum.com Thu Feb 8 08:43:33 2001 From: thomas_g_burke at md.northgrum.com (Burke, Thomas G.) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: ccds responsive at 808 nm? Message-ID: <51FBD4A8EFD9D111BA7300A0C927DADB03E3EE39@xcgmd008.md.essd.northgrum.com> The following was posted to CCD-world: We have successfully tested a front-side iluminated CCD with QE of about 80% at 700nm... At 800nm, it was still above 50%. This CCD is a 2000x128 array with built-in CDS. The array was shown to have around 80e noise (as I recall). It is made to be connected directly to an ADC (you choose) - I believe 80fps is less than it's maximum speed. However, we have only built 5 of these things, and that was under contract, so I don't believe we have any more. This is why I would imagine they'd be pretty darned expensive... If you like, I could look into more particulars on the device, & whether or not we'd be willing to founder another couple of devices. > -----Original Message----- > From: Miller, Miranda A Ms TRW [SMTP:miranda.miller@nvl.army.mil] > Sent: Tuesday, February 06, 2001 11:54 AM > To: 'ccd-world@astro.ku.dk' > Subject: CCD-world: ccds responsive at 808 nm? > > The following was posted to CCD-world: > > I am working on building an active near-IR polarimeter. I'd like to use a > solid-state sensor rather than an I^2 device, but am having trouble > finding > a ccd which has a quantum efficiency > 50% at 808 nm, and has camera noise > less than 50-100 electrons. I'm also hoping for the ccd to be an > interline > transfer device with a VOD, and an array size around 2048x128, with a > frame > rate around 80 fps. > > Pointers, anyone? > Thanks in advance, > Miranda > > Miranda Miller > Electro-Optics Engineer > TRW Systems / Nightvision Labs > mailto: miranda.miller@nvl.army.mil > voice: (703) 704-2741, fax: (703) 704-1345 > > - -- CCD-world -- -- > CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk > Standard replies will go to the list; address personal replies manually. > For more information, please go to: http://www.not.iac.es/CCD-world/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From k_smith at routes.com Thu Feb 8 09:43:59 2001 From: k_smith at routes.com (Ken Smith) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: Crystal growth in a spectrograph slit References: <3A81FC5D.3D5C1539@boao.re.kr> Message-ID: <3A82A29F.31E31461@routes.com> The following was posted to CCD-world: Dear CCD-World: Now that CCD-world has come busy again, this is another question not directly related to CCDs, but rather about an instrument that uses a CCD (for the curious, it is a custom device made by EEV/Marconi). We have built an imaging spectrograph a few years ago and noticed in the more recent flat-field data that there was a strange variation in the spatial dimension of the data. After much head-scratching, the slit was inspected remotely with a telescope and it would appear that the metal slit has in-grown whiskers or crystals. Simulation appears to support the hypothesis. The spectrograph is not easily taken apart and put back together, and therefore direct inspection has not been attempted. Has anyone heard of this sort of phenomena in spectrograph slits or even knife edges, and can reference any literature ? I am aware of this general phenomena, especially with certain metals (eg. Cadmium) in vacuum and also in certain ceramic capacitors. Thanks, Ken Smith Routes AstroEngineering Ltd Ottawa, Canada P.S. I am an electronics/electro-optical engineer, and can't speak by myself on the metallugical details of the slit design, I just did the CCD part of this instrument. - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From ffavata at estsa2.estec.esa.nl Fri Feb 9 16:56:29 2001 From: ffavata at estsa2.estec.esa.nl (ffavata@estsa2.estec.esa.nl) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: LED wavelenght temperature variations? Message-ID: <200102091456.PAA05052@astro.estec.esa.nl> The following was posted to CCD-world: Dear CCD gurus, allow me a somewhat peripheral question: we are thinking of using an LED to calibrate the wavelength response of a detector (yes, we know the LED is not monochromatic, but in this case it is sufficient for the purpose). The question I have is that I have been told that "it is well known" that the "effective wavelength" emitted by the LED changes with temperature (I was told "because of changes in the material bandgap", whatever that means :-) Given that the temperature in the dome changes significantly during the night (even more in comparison with the daytime calibrations) this would be a serious issue. But, I have not been able to locate any documentation where this effect would be quantified (i.e. how many Angstrom, or per cent, of wavelength change per degree should one expect?). Is anybody able to point me to some relevant source of information? Thanks in advance, Fabio -- Fabio Favata Astrophysics Division, European Space Agency - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From deg at panisse.lbl.gov Fri Feb 9 10:12:54 2001 From: deg at panisse.lbl.gov (Don Groom) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: LED wavelenght temperature variations? In-Reply-To: <200102091456.PAA05052@astro.estec.esa.nl> Message-ID: The following was posted to CCD-world: Dear Fabio and others, The only place I know where the temperature dependence of the silicon absorption length (and bandgap position) is discussed is in an obscure paper pointed out to me by Steve Holland: Rajkanan, Singh, and Shewchun, Solid-State Electronics 22, 793 (1979). You can find a graph, tables, and an IDL program to calculate the function by clicking on "Optical Data" at ccd.lbl.gov. I don't know enough about photodiodes to directly answer your question, but we've done considerable modeling of CCD QE using this function. (See SPIE 3649, 80-90 (1999) or get the paper from the above web page.) The effect on QE is small except as one approaches the bandgap, which might relate to emission by a red LED. Modeling of a 200 um thick totally depleted CCD shows that the falling red edge of the QE moves by 3 nm / deg C at lambda = 1000 nm, where the QE is supposed to be 50%. Even this small change is essentially eliminated if one filters out light redder than 900 nm. Don -|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|- Don Groom (Particle Data Group, Supernova Cosmology Project) DEGroom@lbl.gov http://ccd.lbl.gov Voice: 510/486-6788 FAX: 510/486-4799 Analog: 50-308//Berkeley Lab//Berkeley, CA 94720 - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From cno at caltel.com Fri Feb 9 11:47:26 2001 From: cno at caltel.com (Michael McNeil) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: LED wavelenght temperature variations? References: <200102091456.PAA05052@astro.estec.esa.nl> Message-ID: <3A843B3E.1E5AB8D2@caltel.com> Fabio, I have been working very serious on LED's as a reference for a Grism type spectrometer. Nichia, has the first good Uv 350 nm LED that is very accurate at the peak. It widens out some what but on at the bottom, so if you use a scale of 1 to 10, it widens at 1 and hold stability in various temps. Infineon is testing some for me, and said the big deal is to burn in the LED, not the Uv one but others like a 700 nm red LED. Then get them test for wavelength, but running at half the rated current, that is where they maintain stability. But the RED standard LED's are wide, but there are very sharp filters that can be used that allow a 1.5 to 2 nm HW, so the peak would be more stable and accurate. For testing I'm using a dual team of LM317's, one for the regulator and the second for the current limiter. Using some hobby 12" long aluminum tubing that a T1 3/4 fits into, then cut to about 3/4" long with additional tubing to telescope down the size to fit my fiber bundles. This with the lamp on, gets warm and keeps a good temp. for the LED. Infineon assures me that these LED's become stable providing you heed the 1/2 current level. The Uv is a bit different, to where I simply dropped the current to just above cut off. My operation is of simplicity, being disabled, and trying to help the local schools is my main operation so I have to build much of my equipment, such as my poor man spectrometer. As I'm unable to have 120 VAC in the dome the regular lamps like Argon are out, so the LED idea is my latest concern. Mike http://www.caltel.com/~cno/ Camanche North Observatory -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.ctio.noao.edu/pipermail/ccd-world/attachments/20010209/f208e807/attachment.htm From cno at caltel.com Fri Feb 9 14:07:37 2001 From: cno at caltel.com (Michael McNeil) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: LED wavelenght temperature variations? References: <200102091456.PAA05052@astro.estec.esa.nl> <3A843B3E.1E5AB8D2@caltel.com> Message-ID: <3A845C18.1B9E1D13@caltel.com> The following was posted to CCD-world: I should of added, that when they, Infineon, recommended the burn in, it was for 5 days continuous, at full ratings, current and voltage. Then they will perform there calibration testing at the half current range. When they return to me, I will have to set up a current limiter for each LED. Also one point is that the output will go down, so selecting a higher out put to begin with is recommended, unless your going to pipe it right to the CCD such as via fiber bundle. My 2 references are side by side fiber bundles, pointing right into the top area of the CCD, so when I go to work on the software, after binning the image spectra I then bin the 2 dots of reference, to calibrate the spectra wavelength. So the same should work for you in your testing. I also have a 880 nm diode going out for said test. I'm not set up to make these test but have had several offer there assistance in doing so. In my case they are turned on for a very short time, during the initial exposure. Mike - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From Paul.Jorden at marconi.com Tue Feb 13 09:57:36 2001 From: Paul.Jorden at marconi.com (Paul.Jorden@marconi.com) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: LED wavelenght temperature variations? Message-ID: The following was posted to CCD-world: Hi Fabio, > Dear CCD gurus, allow me a somewhat peripheral question: we > are thinking of using an LED to calibrate the wavelength response of a > detector (yes, we know the LED is not monochromatic, but in this case > it is sufficient for the purpose). The question I have is that I have > been told that "it is well known" that the "effective wavelength" > emitted by the LED changes with temperature (I was told "because of > changes in the material bandgap", whatever that means :-) Given that > the temperature in the dome changes significantly during the night > (even more in comparison with the daytime calibrations) this would be > a serious issue. But, I have not been able to locate any documentation > where this effect would be quantified (i.e. how many Angstrom, or per > cent, of wavelength change per degree should one expect?). Is anybody > able to point me to some relevant source of information? > I cannot answer your question about LED wavelength shifts, but I do know that the intensity is a strong function of temperature. In fact, in the RGO days, Simon Tulloch built some temperature calibrated LED calibration units. So if the wavelength shifts, perhaps temperature compensation is the answer? I think you will find technical notes describing them at- http://vela.ing.iac.es/Astronomy/observing/manuals/man_tn.html [or contact Simon; smt@ing.iac.es] Regards, Paul _________________________________________________________ Dr Paul Jorden, CCD Sensors, Marconi Applied Technologies Waterhouse Lane, Chelmsford, Essex, CM1 2QU, UK Tel: +44 (0)1245 453458 (direct), -493493 (switchboard) Fax: +44 (0)1245 453224 (direct), -492492 (general) http://www.marconitech.com/ccds/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From Paul.Jorden at marconi.com Tue Feb 13 11:55:24 2001 From: Paul.Jorden at marconi.com (Paul.Jorden@marconi.com) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: new Marconi web pages (repeat) Message-ID: The following was posted to CCD-world: Ladies & Gents, You may be interested to know that we have recently updated our company's web pages. Hopefully you will be able to find more information of use to you. I'd welcome any comments. This is the link to the ccd product section. http://www.marconitech.com/ccds/ There is an updated 'for sale' page, more astronomy pages, and details of the new 'L3vision' sub-electron noise chips... Best wishes, Paul J _________________________________________________________ Dr Paul Jorden, CCD Sensors, Marconi Applied Technologies Waterhouse Lane, Chelmsford, Essex, CM1 2QU, UK Tel: +44 (0)1245 453458 (direct), -493493 (switchboard) Fax: +44 (0)1245 453224 (direct), -492492 (general) http://www.marconitech.com/products/ccd/ccdprod.html - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From Richard.Kuhns at kirtland.af.mil Tue Feb 13 15:19:00 2001 From: Richard.Kuhns at kirtland.af.mil (Kuhns Richard Capt AFRL/DES) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: LED wavelenght temperature variations? Message-ID: The following was posted to CCD-world: Fabio, Here is the silicon band gap references I have as a function of temperature. In all cases the constants in the equation are found by fitting experimental data but are generally accepted from what I understand. Eg(T)=Eg(0)- (alpha * T^2) / (T+Beta) Where: T = temperature in K Eg = Band Gap of Si But the following Coefficients are given: Eg(0) = 1.170 (Bandgap at 0 K) alpha = 4.730 x 10^-4 Beta = 636 The References are: Sze S.M., Physics of Semiconductor Devices Second Edition 1981 Pg 15 or Robert F. Pierret, Volume VI Modular Series on Solid State Devices Advanced Semiconductor Fundamentals, 1987 pg 85,86 Cheers Rich -----Original Message----- From: ffavata@estsa2.estec.esa.nl [mailto:ffavata@estsa2.estec.esa.nl] Sent: Friday, February 09, 2001 7:56 AM To: CCD-world@astro.ku.dk Cc: ffavata@estsa2.estec.esa.nl Subject: CCD-world: LED wavelenght temperature variations? The following was posted to CCD-world: Dear CCD gurus, allow me a somewhat peripheral question: we are thinking of using an LED to calibrate the wavelength response of a detector (yes, we know the LED is not monochromatic, but in this case it is sufficient for the purpose). The question I have is that I have been told that "it is well known" that the "effective wavelength" emitted by the LED changes with temperature (I was told "because of changes in the material bandgap", whatever that means :-) Given that the temperature in the dome changes significantly during the night (even more in comparison with the daytime calibrations) this would be a serious issue. But, I have not been able to locate any documentation where this effect would be quantified (i.e. how many Angstrom, or per cent, of wavelength change per degree should one expect?). Is anybody able to point me to some relevant source of information? Thanks in advance, Fabio -- Fabio Favata Astrophysics Division, European Space Agency - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From cgt at aaoepp.aao.gov.au Wed Feb 14 15:44:09 2001 From: cgt at aaoepp.aao.gov.au (Chris Tinney) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: AAO WFI/MITLL CCD performance Message-ID: <200102140344.f1E3i9618361@further.aao.gov.au> A non-text attachment was scrubbed... Name: not available Type: text Size: 1473 bytes Desc: not available Url : http://www.ctio.noao.edu/pipermail/ccd-world/attachments/20010214/271ece43/attachment.bat From appell at nasw.org Thu Mar 1 11:06:11 2001 From: appell at nasw.org (David Appell) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: CCD article input requested Message-ID: <3A9E6563.1052@nasw.org> The following was posted to CCD-world: Hello. I'm a journalist working on an article for IEEE SPECTRUM magazine about cutting-edge work in CCD research, design, and applications. I'd be interested in any such work members of this list might be involved in, or suggestions you might have for applications-of-note that I should be sure to cover (even if you think I might already know about them). You can write me directly, or on the list. My deadline is next Friday, 3/9. Thanks, David -- David Appell e: appell@nasw.org p: 603-293-0866 f: 815-333-1486 m: 18 Ridgeline Loop, Gilford, NH 03249 w: http://www.nasw.org/users/appell - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From ccumani at eso.org Fri Mar 2 16:56:55 2001 From: ccumani at eso.org (Claudio Cumani) Date: Thu Jul 29 11:52:03 2004 Subject: CCD-world: CCD article input requested References: <3A9E6563.1052@nasw.org> Message-ID: <3A9FB4B7.A4814AB7@eso.org> The following was posted to CCD-world: A quite unique technique to operate CCD is described in: Cumani C., Mantel K.-H. "Phase resolved high speed photometry and spectroscopy of Pulsars with the ESO FIERA CCD Controller" in "Optical Detectors for Astronomy 2" (proceedings of the "4th ESO CCD Workshop", Garching, September 13-16, 1999) - P. Amico & J.W. Beletic Eds. - Kluwer Academic Publishers (2000) You can find this article at the url: http://www.eso.org/~ccumani/doc/1999CcdWs_article.html As far as we know, it's the first time that the possibility of shifting the charges on the CCD is used during the aquisition of the signal, at least in astronomy. Best greetings Claudio Cumani David Appell wrote: > > The following was posted to CCD-world: > > Hello. I'm a journalist working on an article for IEEE SPECTRUM magazine about > cutting-edge work in CCD research, design, and applications. I'd be interested in > any such work members of this list might be involved in, or suggestions you might have > for applications-of-note that I should be sure to cover (even if you think I might > already know about them). You can write me directly, or on the list. > > My deadline is next Friday, 3/9. > > Thanks, > David > -- > David Appell > e: appell@nasw.org > p: 603-293-0866 > f: 815-333-1486 > m: 18 Ridgeline Loop, Gilford, NH 03249 > w: http://www.nasw.org/users/appell > > - -- CCD-world -- -- > CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk > Standard replies will go to the list; address personal replies manually. > For more information, please go to: http://www.not.iac.es/CCD-world/ -- z |\ _,,,---,,_ z /,`.-'`' -. ;-;;,_ ___________ |,4- ) )-,_. ,\ ( `'-'_________________________________ '---''(_/--' `-'\_) Claudio Cumani E-Mail : ccumani@eso.org European Southern Observatory URL : http://www.eso.org/~ccumani/ Karl-Schwarzschild str. 2 Voice : +49-89-3200-6751 D-85748 Garching bei Muenchen Fax : +49-89-3202362 ______________________________________________________________________ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From ninkov at cis.rit.edu Fri Mar 2 12:29:11 2001 From: ninkov at cis.rit.edu (Zoran Ninkov) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: CCD article input requested References: <3A9E6563.1052@nasw.org> <3A9FB4B7.A4814AB7@eso.org> Message-ID: <3A9FCA57.CFDFA520@cis.rit.edu> The following was posted to CCD-world: Claudio, regards : "As far as we know, it's the first time that the possibility of shifting the charges on the CCD is used during the aquisition of the signal, at least in astronomy." A similar method has been used by us for capturing images (not spectra) for speckle astronomy. For more details see ; Horch E., Ninkov Z. and Slawson R. [1997] "CCD Speckle Observations of Binary Stars from the Southern Hemisphere", Astronomical Journal vol 114, 2117 For speckle we also need to capture rapid sequences of images (1/60 sec each say)and so we stored them on chip in a column to save the overhead of reading each frame. We now have a small scanning mirror in place that allows us to fill the CCD entirely with small subarrays (128 x 128 pixel subarrays on a 4K x 4K CCD) of speckle images - the mirror sweeps along the row and the clocks are used to shift the images down 128 rows when we have moved completely across the columns of the array. This method also allows us to use slow scan, low noise CCDs for this work. While readout is occurring we are slewing to the next target. Recent results can be found in Horch, Franz & Ninkov [2000] Astronomical Journal vol 120, 2638. Cheers, Zoran -- Dr. Zoran Ninkov Center for Imaging Science Rochester Institute of Technology 54 Lomb Memorial Drive Rochester NY 14623-5604 U.S.A. Telephone : 716 - 475 7195 Fax : 716 - 475 5988 e-mail : ninkov@cis.rit.edu - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From craig at sunspot.noao.edu Fri Mar 2 10:29:58 2001 From: craig at sunspot.noao.edu (Craig Gullixson) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: CCD article input requested Message-ID: <200103021629.JAA04436@umbra.sunspot.noao.edu> A non-text attachment was scrubbed... Name: not available Type: text Size: 1870 bytes Desc: not available Url : http://www.ctio.noao.edu/pipermail/ccd-world/attachments/20010302/95fe8fe8/attachment.bat From jkmccarthy at pacbell.net Fri Mar 2 10:01:49 2001 From: jkmccarthy at pacbell.net (Jim McCarthy) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: CCD article input requested References: <3A9E6563.1052@nasw.org> <3A9FB4B7.A4814AB7@eso.org> Message-ID: <3A9FD1FD.E61D1F6D@pacbell.net> The following was posted to CCD-world: Claudio Cumani wrote: > > As far as we know, it's the first time that the possibility of > shifting the charges on the CCD is used during the aquisition of > the signal, at least in astronomy. Back in the mid/late 1980s, Ken Libbrecht at Caltech acquired high spectral and time resolution coude' spectra of rapidly-oscillating Ap stars with the Hale Telescope at Palomar, using a CCD in continuous readout mode identical to method 2.1 in your paper. Please refer to: http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1988ApJ...330L..51L for further details. Jim McCarthy jkmccarthy@pacbell.net - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From ccumani at eso.org Fri Mar 2 19:05:00 2001 From: ccumani at eso.org (Claudio Cumani) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: CCD article input requested References: <3A9E6563.1052@nasw.org> <3A9FB4B7.A4814AB7@eso.org> <3A9FCA57.CFDFA520@cis.rit.edu> Message-ID: <3A9FD2BC.AB0BD4A9@eso.org> The following was posted to CCD-world: Dear Zoran Ninkov, Craig Gullixson, and all the others who - I am sure ! :-) - will reply: thank you a lot for the useful and interesting urls and/or bibliography ! Cheers Claudio -- z |\ _,,,---,,_ z /,`.-'`' -. ;-;;,_ ___________ |,4- ) )-,_. ,\ ( `'-'_________________________________ '---''(_/--' `-'\_) Claudio Cumani E-Mail : ccumani@eso.org European Southern Observatory URL : http://www.eso.org/~ccumani/ Karl-Schwarzschild str. 2 Voice : +49-89-3200-6751 D-85748 Garching bei Muenchen Fax : +49-89-3202362 ______________________________________________________________________ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From Les.Saddlemyer at nrc.ca Fri Mar 2 10:06:22 2001 From: Les.Saddlemyer at nrc.ca (Saddlemyer, Les) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: CCD article input requested Message-ID: <0B39C62869FED21181C90004ACE532DD010F918F@nrcvicex1.hia.nrc.ca> The following was posted to CCD-world: My two cents worth: Doug Welch at DAO performed a similar observation about 8 years ago to gather wavelength dependant occultation observations. I don't know if anything was published. Cheers, Leslie Saddlemyer Research Council Officer, NRC Canada, HIA 250-363-0060 (FAX: 250-363-0045) Email: Leslie.Saddlemyer@hia.nrc.ca -----Original Message----- From: Zoran Ninkov [mailto:ninkov@cis.rit.edu] Sent: Friday, March 02, 2001 8:29 AM To: CCD-world@astro.ku.dk Subject: Re: CCD-world: CCD article input requested The following was posted to CCD-world: Claudio, regards : "As far as we know, it's the first time that the possibility of shifting the charges on the CCD is used during the aquisition of the signal, at least in astronomy." A similar method has been used by us for capturing images (not spectra) for speckle astronomy. For more details see ; Horch E., Ninkov Z. and Slawson R. [1997] "CCD Speckle Observations of Binary Stars from the Southern Hemisphere", Astronomical Journal vol 114, 2117 For speckle we also need to capture rapid sequences of images (1/60 sec each say)and so we stored them on chip in a column to save the overhead of reading each frame. We now have a small scanning mirror in place that allows us to fill the CCD entirely with small subarrays (128 x 128 pixel subarrays on a 4K x 4K CCD) of speckle images - the mirror sweeps along the row and the clocks are used to shift the images down 128 rows when we have moved completely across the columns of the array. This method also allows us to use slow scan, low noise CCDs for this work. While readout is occurring we are slewing to the next target. Recent results can be found in Horch, Franz & Ninkov [2000] Astronomical Journal vol 120, 2638. Cheers, Zoran -- Dr. Zoran Ninkov Center for Imaging Science Rochester Institute of Technology 54 Lomb Memorial Drive Rochester NY 14623-5604 U.S.A. Telephone : 716 - 475 7195 Fax : 716 - 475 5988 e-mail : ninkov@cis.rit.edu - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From deg at panisse.lbl.gov Fri Mar 2 10:41:17 2001 From: deg at panisse.lbl.gov (Don Groom) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: Charge shifting In-Reply-To: <3A9FCA57.CFDFA520@cis.rit.edu> Message-ID: The following was posted to CCD-world: ?? In addition to the Coude work Jim McCarthy mentioned, I think Jim Gunn, Maartin Schmidt, and collaborators used charge-shifting to obtain drift- scan images at Palomar perhaps 15 years ago, using a single very small CCD. The telescope RA drive was shut off and continuous readout compensated for the earth's rotation, producing scrolled images. This is described in the popular book "First Light" by Richard Preston. -|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|- Don Groom (Particle Data Group, Supernova Cosmology Project) DEGroom@lbl.gov http://ccd.lbl.gov Voice: 510/486-6788 FAX: 510/486-4799 Analog: 50-308//Berkeley Lab//Berkeley, CA 94720 - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From jcc at cfht.hawaii.edu Fri Mar 2 23:13:07 2001 From: jcc at cfht.hawaii.edu (Jean-Charles Cuillandre) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: CCD article input requested In-Reply-To: <3A9FB4B7.A4814AB7@eso.org> from "Claudio Cumani" at Mar 02, 2001 03:56:55 PM Message-ID: <200103030813.WAA06588@hokua.cfht.hawaii.edu> The following was posted to CCD-world: Hi, It is important to give credit for the original idea and implementation to Ian S. McLean back in 1981 (Mc Lean et al. 1981 SPIE 290 155) for shifting back and forth an on-chip image for a polarimetry application requiring precise time sampling. We developed a similar technique for spectroscopy in the early 90s (Cuillandre et al. A&A, 1994, 281, 603 available in http://www.cfht.hawaii.edu/~jcc/Publications/publications.html) to preserve sky photon noise regime in the data. Low level spectroscopy is limited by the sky subtraction and that technique we call "Back and Forth Spectroscopy" saves you from that by doing a pixel to pixel correction and shifting the charges back and forth from underneath a mask during the exposure, hence no readout, it saves from the flat-field residuals, artifacts on the slit since the light is integrated on the same path (it is at ease with curved slits for example), etc... It's been implemented and tested at CFHT on the multi-object spectrograph and it is really neat (it implies the telescope offsetting also). Several articles renaming/reinventing this technique have appeared since, and one is a nice in depth analysis of the application on the AAT fiber spectrograph: http://xxx.lanl.gov/abs/astro-ph/0011104 and expose its high multiplexing potential. Mhhh, this whole thing raises the question of the exposure of technical publications: SPIE proceedings are not available to everybody and engineers don't necessarily check the astronomical publications. So, bright people get to have bright ideas but not at the same time. The early work should prevail but what could be done about it? Maybe evolved search engine will do if the publishers are open to at least have the abstracts available (I am thinking of SPIE in particular). Any thoughts? JCC -------------------------------------------------------------------------------- Dr. Jean-Charles Cuillandre Tel: (808) 885-3128 Canada-France-Hawaii Telescope Corporation Fax: (808) 885-7288 P.O. Box 1597 E-mail: jcc@cfht.hawaii.edu Kamuela, Hawaii 96743 USA HTML: http://www.cfht.hawaii.edu/~jcc -------------------------------------------------------------------------------- - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From dennefel at iap.fr Sat Mar 3 13:08:38 2001 From: dennefel at iap.fr (Michel Dennefeld) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: Set-up of a list of basic references References: <200103030813.WAA06588@hokua.cfht.hawaii.edu> Message-ID: <3AA0D0B6.33D8@iap.fr> The following was posted to CCD-world: Following the recent, rather incredible annoucement of a "new technique" implemented on charge drift, while it was know since many years, I wonder whether the "CCD list" could not make a valuable contribution for newcomers (and others!), in setting up a list of fundamental references for all what concerns CCD manufacturing and practical use? We see often many good explanations given, and references quoted in the e-mails, answering particular questions: if all these references would simply be compiled and put on a Web page, this would make a very interesting reference list. And if each CCD-gourou would provide,say, 10 references he considers as fundamental in his speciality, even better.... Would the CCD-list manager consider this as feasible (and acceptable) task? It would also greatly help all those who are teaching in the field! Michel Dennefeld - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From cgt at aaoepp.aao.gov.au Sun Mar 4 00:13:08 2001 From: cgt at aaoepp.aao.gov.au (Chris Tinney) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: CCD article input requested Message-ID: <200103031213.f23CD8I25470@further.aao.gov.au> A non-text attachment was scrubbed... Name: not available Type: text Size: 1010 bytes Desc: not available Url : http://www.ctio.noao.edu/pipermail/ccd-world/attachments/20010303/68f186ab/attachment.bat From jcc at cfht.hawaii.edu Sun Mar 4 22:58:50 2001 From: jcc at cfht.hawaii.edu (Jean-Charles Cuillandre) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: technical publication archive also? In-Reply-To: <200103030813.WAA06588@hokua.cfht.hawaii.edu> from "Jean-Charles Cuillandre" at Mar 02, 2001 10:13:07 PM Message-ID: <200103050758.VAA27767@hokua.cfht.hawaii.edu> The following was posted to CCD-world: Hello, CCD-world is a great forum with tons of highly interesting information exchanged between a community that continues to grow larger. CCD-world provides an archive for all these email exchanges sorted in sequential order. We all eventually get to publish our results in a large range of journals. But the world community is not equally served to access these publications like I said the other day. Astro-ph changed the landscape of access to the latest hot results in astrophysics with its preprint server. Information goes faster and reaches more people, a simple browser is needed along with the willingness of the authors to go through the submission process (there is no peer review, so it relies on a code of ethic regarding the contain and quality of the work put on astro-ph). Anyway, regarding CCD (&IRFPA!) technical publications, some of the old journals go out of print and the information is lost for the newcomers. The result in the "re-invention" of techniques. Hence I would propose a CCD-world technical publication server: not only it would contain the latest publications, but we could all try to dig out or old PostScript files to recreate a database up to 20-25 years ago away (for some of you, hey I've been around for only 8 years!). Postscript or PDF could be the standard, unlike astro-ph that requires use of LateX, which may not be that popular within the engineering community. Each file should come with its initial publication reference (the question is, are there some copyright issues in some cases?). Could we consider a scanning in the desperate cases? Tim, you are managing the list and an article server is extra work to ask from you (though if we stick to PS or PDF files, the posting procedure should be quite simple). Let us know about that before we all start getting wild on the idea. Jean-Charles. -------------------------------------------------------------------------------- Dr. Jean-Charles Cuillandre Tel: (808) 885-3128 Canada-France-Hawaii Telescope Corporation Fax: (808) 885-7288 P.O. Box 1597 E-mail: jcc@cfht.hawaii.edu Kamuela, Hawaii 96743 USA HTML: http://www.cfht.hawaii.edu/~jcc -------------------------------------------------------------------------------- - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From bortolet at techne.pd.astro.it Mon Mar 5 11:04:06 2001 From: bortolet at techne.pd.astro.it (Fabio Bortoletto) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: CCD article input requested In-Reply-To: <3A9FB4B7.A4814AB7@eso.org> Message-ID: The following was posted to CCD-world: Hi Claudio, one of the first pictures of the comet Halley has been obtained in 84 at the Asiago Observatory (Italy) with the following procedure: - telescope drives stopped - CCD rotated with columns along the object trajectory on the sky - then exposing and tracking the object motion shifting the charge at the required speed. Bye, Fabio. Bonoli C., Bortoletto F., D'Alessandro, Scardia M., "THE RECOVERY OF HALLEY COMET AT ASIAGO OBSERVATORY" 1985, Mem. S.A.It., 56, 777 +-----------------------------------------------------------------------+ Fabio Bortoletto: Italy: Spain: Osservatorio Astronomico Centro Galileo Galilei Vicolo Osservatorio 5 Apartado de Correos, 565 35122 Padova - ITALY E-38700 S/C, de La Palma - Tenerife (ESPAGNA) Tel. +39 049 8293485 Tel. +34 922 425043 (S. Cruz) Fax. +39 049 8759840 bortoletto@pd.astro.it bortoletto@tng.iac.es +-----------------------------------------------------------------------+ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From tabbott at not.iac.es Mon Mar 5 13:22:44 2001 From: tabbott at not.iac.es (Tim Abbott) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: Good intentions... Message-ID: The following was posted to CCD-world: Dear CCD-world, The road to hell, they say, is paved with good intentions... These suggestions to build a bibliography on the CCD-world web page, or possibly to serve reprints (Oof! Be gentle with me, JC!), have scratched my guilty conscience. From time to time, I have put some thought into making CCD-world more useful, and I have also discussed a number of options with various people at the ESO workshops (you know who you are!). But so far the real world has intruded to block progress in the virtual. That's not to say that these ideas are not good ones. Some others which have occured to me are: * An FAQ and glossary of terms (I actually started this, but realised that to make it more useful than what was already available, I would effectively be writing a book...) * Asking for volunteers to write short articles on topics in which they are expert. (What say, any volunteers?) * Condensing a "knowledge-base" from CCD-world (interesting, but a considerable editing task, and anyone can read the archives anyway.) Well, the only thing that is likely to make progress is a concrete plan of action, so I'll do this: 1) A short bibliography of "classic" texts. I'll throw something together, put it on the web site, then you can all tell me the items I should defintely have included... 2) I'll dust off the FAQ idea and see what can be done with it, possibly combining it with: 3) A request for volunteers to write short articles or "FAQ" answers. If I don't get any unsolicited "volunteers", I shall pick some and start bugging them. Your sucker-for-punishment moderator, Tim P.S. I doubt that I'd be able to serve any preprints for copyright reasons. If ADS can't serve SPIE articles, I doubt that I'd have any better luck. On the other hand, if anyone wants to send me any articles which they know can be freely served from CCD-world, I'm happy to add them. -- Tim Abbott, Astronomer-in-Charge, Nordic Optical Telescope tabbott@not.iac.es, http://www.not.iac.es/~tabbott/, +34 922 425 472 Roque de Los Muchachos & Santa Cruz de La Palma, Canary Islands, Spain - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From cdm at ast.cam.ac.uk Mon Mar 5 18:26:28 2001 From: cdm at ast.cam.ac.uk (Craig D Mackay) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: CCD article input requested References: <3A9E6563.1052@nasw.org> <3A9FB4B7.A4814AB7@eso.org> Message-ID: <3AA3CC44.F4FF46F5@ast.cam.ac.uk> The following was posted to CCD-world: Dear Claudio To the best of my knowledge, the first astronomical application of a CCD that was clocked in synchronism with the movement of the image while taking data was the original drift-scan method described in Wright and Mackay, SPIE, 290, p161, 1981. First results are described. The method was later applied to deep galaxy counts at high latitudes, reaching approximately 27 mag, a level recently exceeded with the HST. These results are described in Hall and Mackay, MNRAS 210, p979-992, 1984. Best Wishes Craig D Mackay. - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From cdm at ast.cam.ac.uk Mon Mar 5 18:43:23 2001 From: cdm at ast.cam.ac.uk (Craig D Mackay) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: CCD article input requested References: <3A9E6563.1052@nasw.org> Message-ID: <3AA3D03B.49D0CA20@ast.cam.ac.uk> The following was posted to CCD-world: Dear David As part of your search for the latest developments, you may be interested in a new paper presented at the SPIE conference in San Jose in January entitled: "Sub-Electron Read Noise at MHz Pixel Rates" by Craig D. Mackay, Robert N. Tubbs, (Institute of Astronomy, University of Cambridge),Ray Bell, David Burt, Paul Jerram, Ian Moody (Marconi Applied Technologies). The Abstract says: "A radically new CCD development by Marconi Applied Technologies has enabled substantial internal gain within the CCD before the signal reaches the output amplifier. With reasonably high gain, sub-electron readout noise levels are achieved even at MHz pixel rates. This paper reports a detailed assessment of these devices, including novel methods of measuring their properties when operated at peak mean signal levels well below one electron per pixel. The devices are shown to be photon shot noise limited at essentially all light levels below saturation. Even at the lowest signal levels the charge transfer efficiency is good. The conclusion is that these new devices have radically changed the balance in the perpetual trade-off between readout noise and the speed of readout. They will force a re-evaluation of camera technologies and imaging strategies to enable the maximum benefit to be gained from these high-speed, essentially noiseless readout devices. This new LLLCCD technology, in conjunction with thinning (backside illumination) should provide detectors which will be very close indeed to being theoretically perfect." A copy of the pdf file may be found on http://www.ast.cam.ac.uk/~optics/cdm/Sub_electron_paper_03.pdf Best Wishes Craig D Mackay. - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From Peter.Pool at marconi.com Mon Mar 5 19:49:49 2001 From: Peter.Pool at marconi.com (Peter.Pool@marconi.com) Date: Thu Jul 29 11:52:04 2004 Subject: CCD-world: CCD article input requested Message-ID: The following was posted to CCD-world: You'll find Craig's paper and some others at : http://www.marconitech.com/ccds/lllccd/technology.html Peter Pool Marconi Applied Technologies -----Original Message----- From: MIME :cdm@ast.cam.ac.uk Sent: 05 March 2001 18:01 To: CCD-world@astro.ku.dk Subject: Re: CCD-world: CCD article input requested The following was posted to CCD-world: Dear David As part of your search for the latest developments, you may be interested in a new paper presented at the SPIE conference in San Jose in January entitled: "Sub-Electron Read Noise at MHz Pixel Rates" by Craig D. Mackay, Robert N. Tubbs, (Institute of Astronomy, University of Cambridge),Ray Bell, David Burt, Paul Jerram, Ian Moody (Marconi Applied Technologies). The Abstract says: "A radically new CCD development by Marconi Applied Technologies has enabled substantial internal gain within the CCD before the signal reaches the output amplifier. With reasonably high gain, sub-electron readout noise levels are achieved even at MHz pixel rates. This paper reports a detailed assessment of these devices, including novel methods of measuring their properties when operated at peak mean signal levels well below one electron per pixel. The devices are shown to be photon shot noise limited at essentially all light levels below saturation. Even at the lowest signal levels the charge transfer efficiency is good. The conclusion is that these new devices have radically changed the balance in the perpetual trade-off between readout noise and the speed of readout. They will force a re-evaluation of camera technologies and imaging strategies to enable the maximum benefit to be gained from these high-speed, essentially noiseless readout devices. This new LLLCCD technology, in conjunction with thinning (backside illumination) should provide detectors which will be very close indeed to being theoretically perfect." A copy of the pdf file may be found on http://www.ast.cam.ac.uk/~optics/cdm/Sub_electron_paper_03.pdf Best Wishes Craig D Mackay. - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From reinhold.dorn at eso.org Mon Mar 5 20:22:54 2001 From: reinhold.dorn at eso.org (Reinhold Dorn) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: CCD article input requested / A new CCD design References: <3A9E6563.1052@nasw.org> Message-ID: <3AA3D97E.C4D3C42B@eso.org> The following was posted to CCD-world: Hello David, You may find the following paper on a special designed CCD for curvature wavefront sensing of interest. Curvature AO-systems have traditionally used avalanche photo diodes (APDs) as detectors due to strict requirements of very short integration times (200 microsec) and very low readout noise. A CCD has never been used before as the wavefront sensor in a curvature adaptive optics system. This CCD archives nearly the same performance as APDs and has the potential to work as well as APDs with reduced complexity for high order wavefront correction. Moreover the CCD has a higher quantum efficiency than APDs and the new design with multiple readout ports and storage sections compensates significantly the time lag which was limiting the bandwidth of the servo loop when observing bright objects. In the following paper which can be downloaded from http://www.eso.org/~rdorn/CCID_35.html we presents the concept and the design of this device, which was fabricated at MIT Lincoln Laboratory. The first frontside device is successfully running at < 2 electrons read noise with a readout time of 250 us for the whole device in a laboratory prototype system. All the best, Reinhold Dorn David Appell wrote: > > The following was posted to CCD-world: > > Hello. I'm a journalist working on an article for IEEE SPECTRUM magazine about > cutting-edge work in CCD research, design, and applications. I'd be interested in > any such work members of this list might be involved in, or suggestions you might have > for applications-of-note that I should be sure to cover (even if you think I might > already know about them). You can write me directly, or on the list. > > My deadline is next Friday, 3/9. > > Thanks, > David -------------------------------------------------------------------- Reinhold Dorn e-mail: reinhold.dorn@eso.org ESO-European Southern Observatory phone : +49-89-32006-547 K.Schwarzschildstr.2,D-85748 Garching http://www.eso.org/~rdorn -------------------------------------------------------------------- - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From tinbergen at nfra.nl Mon Mar 5 22:34:05 2001 From: tinbergen at nfra.nl (Jaap Tinbergen) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: charge shifting Message-ID: The following was posted to CCD-world: I think Ian himself attributes it to a Stewart Obs proposal by someone whose name I can't recall; I am working from home and can't check. Get Ian's email address from IAU list and check with him, I'd say. Rgds, Jaap Tinbergen Hi, It is important to give credit for the original idea and implementation to Ian S. McLean back in 1981 (Mc Lean et al. 1981 SPIE 290 155) for shifting back and forth an on-chip image for a polarimetry application requiring precise time sampling. We developed a similar techniq - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From ccumani at eso.org Tue Mar 6 16:43:23 2001 From: ccumani at eso.org (Claudio Cumani) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: Charge-shifting and CCD archive - comments and a question References: <200103031213.f23CD8I25470@further.aao.gov.au> <3AA39E86.14EE83CF@eso.org> Message-ID: <3AA4F78B.10BA7D42@eso.org> The following was posted to CCD-world: > if you are not interested/involved in the charge-shifting < > topic, just skip this email < Dear all, After a very interesting and useful weekend spent reading the articles that you all suggested, I have some comments and questions: 1) I have not been precise in the email about my article, and I apologise for that; I should not have spoken about general charge shifting techniques, which are indeed quite old. Many reactions have been very useful: I presented my article at the 4th ESO CCD workshop in 1999 and discussed it with several astronomers since then, and I never received all the information I got in the last days. *grin* The usual comment was "it is indeed something I haven't seen before". But now I know that I was missing some important information: thanks to Zoran Ninkov, Chris Tinney and Jim McCarthy I finally read some articles speaking about one of the techniques described in my article (used at CTIO and AAO). 2) I still have not found an article describing something similar to the tecnique that I call "Periodic-shift-mode". I still think that the idea of SUPERIMPOSING several spectra (or images) of a variable object, moving back and forth the charges on the CCD, keeping the shutter open while moving the charges in one direction (closing it when moving them back), synchronising the motion of the charges with the signal period is really simple, and I cannot imagine that also other people have not tested it. Their experiences might help me to overcome a problem I have found, which prompts the following question: 3) The more back and forth motion I perform, to superimpose several spectra of the object, the more noise I collect on the chip. I am not speaking about the well known "pocket pumping": this noise has an almost parabolic profile along the chip. It is higher at the borders (the first and last parallel registers) and lower in the middle (the central parallel registers) of the chip. We wonder if these charges are spurious charges propagated into the chip from the borders ... but I do not have any explanation for that ... Has anyone of you experienced something like that ? 4) My 2 cents worth about the CCD Archive and this list: The archive would indeed be very useful, but I imagine it would also be difficult to organise and maintain ... And this list works quite well, with a lot of useful news, hints, criticisms ... At least it has worked well for me ! *grin* Again, thank you all a lot for your feedback. Claudio -- z |\ _,,,---,,_ z /,`.-'`' -. ;-;;,_ ___________ |,4- ) )-,_. ,\ ( `'-'_________________________________ '---''(_/--' `-'\_) Claudio Cumani E-Mail : ccumani@eso.org European Southern Observatory URL : http://www.eso.org/~ccumani/ Karl-Schwarzschild str. 2 Voice : +49-89-3200-6751 D-85748 Garching bei Muenchen Fax : +49-89-3202362 ______________________________________________________________________ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From Paul.Jorden at marconi.com Tue Mar 6 16:58:30 2001 From: Paul.Jorden at marconi.com (Paul.Jorden@marconi.com) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: Charge-shifting and CCD archive - comments and a question Message-ID: The following was posted to CCD-world: Claudio, et al, > 2) I still have not found an article describing something similar > to the tecnique that I call "Periodic-shift-mode". > I agree with Jaap Tinbergen's comment- the technique was used ~ 20 years ago for polarimetry at Steward- they accumulated differential polarisation images within the frame. They were plagued by pocket pumping, and perhaps spurious chare, as I recall. > 3) The more back and forth motion I perform, to superimpose several > spectra of the object, the more noise I collect on the chip. I am not > speaking about the well known "pocket pumping": this noise has an > almost parabolic profile along the chip. It is higher at the borders > (the first and last parallel registers) and lower in the middle (the > central parallel registers) of the chip. We wonder if these charges > are spurious charges propagated into the chip from the borders ... > but I do not have any explanation for that ... Has anyone of you > experienced something like that ? > It sounds like you are seeing spurious charge from clock injection. (ie ionisation-induced internal charge from clock voltage swings). Fast, and maximum amplitude, clock edges are more likely to be seen at the edges of the chips. Particularly with high bus impedance you might see the effect strongest at the borders? The magnitude should be proportional to the number of parallel clcok transitions, and would vary with clock amplitude (and perhaps edge shape). regards, Paul _________________________________________________________ Dr Paul Jorden, CCD Sensors, Marconi Applied Technologies Waterhouse Lane, Chelmsford, Essex, CM1 2QU, UK Tel: +44 (0)1245 453458 (direct), -493493 (switchboard) Fax: +44 (0)1245 453224 (direct), -492492 (general) http://www.marconitech.com/ccds/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From bdk at srl.caltech.edu Tue Mar 6 10:50:54 2001 From: bdk at srl.caltech.edu (Brian D. Kern) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: Charge-shifting Message-ID: <200103061750.JAA01433@ull.srl.caltech.edu> A non-text attachment was scrubbed... Name: not available Type: text Size: 1628 bytes Desc: not available Url : http://www.ctio.noao.edu/pipermail/ccd-world/attachments/20010306/032995a5/attachment.bat From dbc at canopus.saao.ac.za Thu Mar 8 16:56:54 2001 From: dbc at canopus.saao.ac.za (Dave Carter) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: Strange question In-Reply-To: Message-ID: The following was posted to CCD-world: I have had a strange question from the engineers building our new telescope (SALT - similar to the HET). As the question would never have occurred to me, let alone knowing the answer, does anybody out there have an opinion? With regard to the environment for the instrumentation room in the basement, and the CCD cosmic-ray-event detection rate: Is there anything to be aware of/avoid in terms of substances used in erecting this room - i.e. re-inforced concrete/steel/insulation etc? Some time ago I recall there being some discussion on this forum regarding what should/shouldn't be used in the cryostat close to the detector, but nothing on the do's and don'ts further away from the CCD. regards +-----------------------------------------------------+ Dave Carter Electronics Lab, S. A. Astronomical Observatory. e-mail : dbc@saao.ac.za Tel ( Nat. ) : 021-4470025 ( Int. ) : 27-21-4470025 Fax ( Nat. ) : 021-4473639 ( Int. ) : 27-21-4473639 +-----------------------------------------------------+ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From paw at canopus.saao.ac.za Thu Mar 8 18:05:31 2001 From: paw at canopus.saao.ac.za (Patricia Whitelock) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: Astronomer/Instrument Scientist wanted (fwd) Message-ID: The following was posted to CCD-world: I'd be grateful if you would distribute the following two adverts to your mail exploder. Thanks Patricia ------------------------------------------------------------------ | Dr Patricia Whitelock | | Deputy Director | | South African Astronomical Observatory | | P O Box 9 Phone: +27 21 4606283 | | 7935 Observatory Fax: +27 21 4473639 | | South Africa email: paw@saao.ac.za | ------------------------------------------------------------------ Astronomer/Instrument Scientist - SAAO The South African Astronomical Observatory (SAAO) seeks an astronomer with a strong interest in infrared/optical instrumentation. The SAAO is the National Facility for optical/infrared astronomy in South Africa. Its headquarters are in Cape Town where the successful applicant will be based. Observing facilities, situated 360 km away at Sutherland, comprise four common-user telescopes and a recently commissioned 1.4-m Infrared Survey Facility (IRSF) run in collaboration with Nagoya University, Japan. Construction of the Southern African Large Telescope (SALT), a 10-m class instrument, should be completed by 2004. The preferred applicant will have experience in working with near-infrared and/or optical CCD arrays. A PhD in astrophysics or a related subject is essential as she/he will also be expected to spend about 50% of their time on research. More details of SAAO, SALT and the current research interests of their staff are available at www.saao.ac.za and www.salt.ac.za. Applicants should submit a curriculum vitae, with a statement of research and instrumentation interests to: The Personnel Officer, Ms Linda Tobin, SAAO, P O Box 9, Observatory, 7935, South Africa, phone: +27 21 4470025; fax: +27 21 4473639; email: linda@saao.ac.za. Applicants should also arrange for three professional referees to supply letters of recommendation to the same address by the due date of 1 April 2001. SAAO is committed to equity. ===================================================================== Astronomical Research Fellow - SAAO Applications are invited for a postdoctoral research fellowship at the South African Astronomical Observatory (SAAO). The appointment will be for two years, with a likely extension to a third year. Preference will be given to candidates with an interest in infrared and/or optical instrumentation. The SAAO is the National Facility for optical/infrared astronomy in South Africa. Its headquarters are in Cape Town where the successful applicant will be based. Observing facilities, situated 360 km away at Sutherland, comprise four common user telescopes and a recently commissioned 1.4-m Infrared Survey Facility (IRSF) run in collaboration with Nagoya University, Japan. Construction of the Southern African Large Telescope (SALT), a 10-m class instrument, should be completed by 2004. While the successful applicant will spend most of their time on research, they will also be encouraged to contribute to the SAAO's instrumentation or software development programmes as well as supporting visiting astronomers. More details of the SAAO, SALT and the current research interests of their staff are available at www.saao.ac.za and www.salt.ac.za. Applicants must have a PhD in astrophysics or a related subject. They should submit a curriculum vitae, with a statement of research and instrumentation interests to: The Personnel Officer, Ms Linda Tobin, SAAO, P O Box 9, Observatory, 7935, South Africa, phone: +27 21 4470025; fax: +27 21 4473639; email: linda@saao.ac.za. Applicants should also arrange for three professional referees to supply letters of recommendation to the same address by the due date of 1 April 2001. SAAO is committed to equity. - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From deg at panisse.lbl.gov Thu Mar 8 10:57:56 2001 From: deg at panisse.lbl.gov (Don Groom) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: Strange question In-Reply-To: Message-ID: The following was posted to CCD-world: Dave Carter and others, Also strange you should ask just now. We've (mostly) finished a fairly extensive series of tests designed to characterize radiation events in CCDs. The tests included long dark exposures in two low-background radiation test facilities (at LBNL and in a facility 160 m underground), the Coude spectrograph room at the Lick 3-m, the prime focus spectrograph at the Kitt Peak PF spectograph, etc. The analysis is mostly done and a paper partly written, but let me make a very brief summary: 1. There is an irreduceable cosmic ray muon background of about 1 /(cm^2 min) in a horizontal CCD. The zenith angle dependence is supposed to be close to cos^2 \theta, so a vertical CCD has fewer but longer tracks. The rate increases with altitude, with the horizontal-CCD rate reaching perhaps 2.3/(cm^2 min) on Mauna Kea. 2. There are also other events *not* of cosmic ray origin. Members of our group have established beyond reasonable doubt that the other events are from energy deposit by Compton-scattered electrons. The soft gammas are environmental---concrete walls, stuffy rooms full of radon, and, without care, some of the things in a dewar. The good news/bad news is that the Compton interaction rate is proportional to the thickness of the active region (assuming no inactive substrate), as should be the average energy deposition. For our thick CCDs (300 um sensitive region) the energy deposition is typically less that 100 keV, with the count rate decreasing rapidly with energy. 3. With a 200 um thick device at the Lick 3-m Coude spectrometer, we found a Compton rate about 3 times higher than the cosmic ray muon rate. Lead shielding was gradually added, and with about 1 cm shielding the Compton rate was somewhat below the cosmic ray rate. 4. The Compton rate was considerable less in the Kitt Peak PF cage (data by Arjun Dey, 300 um thick active region). (3) and (4) are consistent, and consistent with the high Compton rate found in the UCO/Lick lab at Santa Cruz, in a bottom floor room of a poured-concrete building. All of this is consistent with the gammas coming from the U and Th decay chains, common knowledge to low-level radiation experts. One surmises that the enclosed rooms have more radon than the great outdoors of a PF cage, which is also far from the evil concrete. 5. In the best of worlds, one would aim for low U and Th content concrete and ventilated work regions. (The last to be checked.) In the real world, minimal lead shielding around the dewar seems to work. But we have some worrisome data from dark exposures from one of our CCDs taken to Keck that shows no shielding effect; our attempts to understand these data include low-background counting of samples of the lead and Mauna Kea lava, presently under way. 6. There is some evidence (Richard Stover and other sources) that some CCDs have higher rates than others of the same thickness, maybe due to radiological contamination of the nearby materials, such as the black dye in a socket. It's pretty clear that *all* materials in the dewar need to be characterized. We have done so and gotten a clean bill of health, in particular for the silicon wafer itself. The number of lost pixels is more or less proportional to the active region thickness for cosmic rays, and perhaps slightly more than linearly with the region thickness for Compton events (worms and spots). We still have much work to do, and input, e.g. measured rates, would be useful. Don Groom -|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|- Don Groom (Particle Data Group, Supernova Cosmology Project) DEGroom@lbl.gov http://ccd.lbl.gov Voice: 510/486-6788 FAX: 510/486-4799 Analog: 50-308//Berkeley Lab//Berkeley, CA 94720 - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From phil_hobbs at vnet.ibm.com Thu Mar 8 17:19:11 2001 From: phil_hobbs at vnet.ibm.com (Phil Hobbs) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: Strange question Message-ID: <200103082120.QAA26400@sp1n189at0.watson.ibm.com> A non-text attachment was scrubbed... Name: not available Type: text Size: 857 bytes Desc: not available Url : http://www.ctio.noao.edu/pipermail/ccd-world/attachments/20010308/b4dd22b0/attachment.bat From PCDH at watson.ibm.com Thu Mar 15 13:27:34 2001 From: PCDH at watson.ibm.com (Phil Hobbs) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: Thermal Transfer Compounds Message-ID: <200103151837.NAA39542@sp1n189at0.watson.ibm.com> A non-text attachment was scrubbed... Name: not available Type: text Size: 1233 bytes Desc: not available Url : http://www.ctio.noao.edu/pipermail/ccd-world/attachments/20010315/0a64180c/attachment.bat From alain.maury at obs-azur.fr Fri Mar 16 06:02:32 2001 From: alain.maury at obs-azur.fr (Alain Maury) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: Thermal Transfer Compounds References: <200103151837.NAA39542@sp1n189at0.watson.ibm.com> Message-ID: <3AB1E4B8.2C7E933B@obs-azur.fr> The following was posted to CCD-world: Don't stack your peltier yourselves, buy already assembled devices. -100?C in a dry N2 atmosphere with Peltier coolers, huhhh.... good luck ! The best peltier cold boxes which I have seen are been built by Michael Carr at Princeton, and they don't go that cold.... Alain Phil Hobbs a ?crit : > > The following was posted to CCD-world: > > I've been investigating thermal transfer compounds, and man, is there a lot > of snake oil being peddled out there. I've come across silver-loaded greases > and epoxies that claim thermal conductivities from 1 to 60 W/m/K, as the silver > content goes from 60% to 85%. > > Other people I've talked to have mentioned using indium solder paste cold, > without reflowing it, but haven't done a lot of measurements of just how > well it works. > > People also talk about interfacial thermal resistance, so that a plot of > thermal resistance vs. grease thickness has a positive offset as the thickness > goes to 0. > > I want to use stacked TECs to cool an infrared detector to about -100C in > a dry nitrogen atmosphere, which is a stretch, and am clearly going to succeed > or fail based on the thermal compound. > > I'd appreciate data, anecdotes, and pointers to where to find out the real > story. > > Thanks, > > Phil Hobbs > IBM T. J. Watson Research Center > PO Box 218, > Yorktown Heights NY 10598 > > - -- CCD-world -- -- > CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk > Standard replies will go to the list; address personal replies manually. > For more information, please go to: http://www.not.iac.es/CCD-world/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From pcm at ing.iac.es Fri Mar 16 10:05:22 2001 From: pcm at ing.iac.es (Peter Moore) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: Thermal Transfer Compounds In-Reply-To: <200103151837.NAA39542@sp1n189at0.watson.ibm.com> Message-ID: The following was posted to CCD-world: Hi Phil, One I've been looking at but not yet tried is Apiezon N The link to their data sheet is http://www.apiezon.com/greasetable.htm and they advertise (in a seperate circular) that results for thermal and vacuum tests are available from NASSA Ames and Max Planck ('Thermal boundry resistance of mechanical contacts between solids at sub-ambient temperatures' - E.Gmel, M. Asen-Palmer, et al.) It looks a lot better than anything we have here at present ! Best regards, Peter. =+===+===+===+===+===+===+===+===+ ING +===+===+===+===+===+===+===+= = Peter Moore, Isaac Newton Group, La Palma Observatory, Spain. = = E-mail pcm@ing.iac.es Voice Office +34 922 405566 = = S-mail Apartado de Correo 321, Fax Office +34 922 405646 = = 38780 Santa Cruz de La Palma, Voice Home +34 922 435042 = = Canary Islands, Spain. = =+===+===+===+===+===+===+===+===+ LPO +===+===+===+===+===+===+===+= - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From Paul.Jorden at marconi.com Fri Mar 16 10:24:50 2001 From: Paul.Jorden at marconi.com (Paul.Jorden@marconi.com) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: Thermal Transfer Compounds Message-ID: The following was posted to CCD-world: Phil, > I want to use stacked TECs to cool an infrared detector to > about -100C in > a dry nitrogen atmosphere, which is a stretch, and am clearly > going to succeed or fail based on the thermal compound. > > I'd appreciate data, anecdotes, and pointers to where to find > out the real story. > This looks quite demanding. Are you considering buying an assembled stack from a TEC manufacturer- in which case they may solder them together for you? (best solution I assume) In that case you will be left with making good contact with the IR sensor, and with the hot-side mount/ heat removal. thermal compound considerations apply of course. Finally, I would expect that radiative transfer losses would be quite important at this temperature. Since multi-level TEC stacks are inefficient, then minimising heat-load on the cold side is important. [forgive me if you know this already] Regards, Paul _________________________________________________________ Dr Paul Jorden, CCD Sensors, Marconi Applied Technologies Waterhouse Lane, Chelmsford, Essex, CM1 2QU, UK Tel: +44 (0)1245 453458 (direct), -493493 (switchboard) Fax: +44 (0)1245 453224 (direct), -492492 (general) http://www.marconitech.com/ccds/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From cno at caltel.com Fri Mar 16 03:24:09 2001 From: cno at caltel.com (Michael McNeil) Date: Thu Jul 29 11:52:05 2004 Subject: CCD-world: Thermal Transfer Compounds References: <200103151837.NAA39542@sp1n189at0.watson.ibm.com> Message-ID: <3AB1F7D9.F396B490@caltel.com> The following was posted to CCD-world: Hi Phil, I had several years back a 2 day school from Melcor. They have some formulated compound, that seems to work very good. the trick was to rub the Tec to the heat sink till it sticks like glue, and like wise for the detector. I'm not sure, or even if I remember much about it now. I do know it does not out gas as some do, and it seems very fine like a face cream. So you might contact them for some good info. Mike Camanche North Observatory. - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From MBeckett at scigen.co.uk Fri Mar 16 11:51:20 2001 From: MBeckett at scigen.co.uk (Beckett, Martin) Date: Thu Jul 29 11:52:06 2004 Subject: CCD-world: Thermal Transfer Compounds Message-ID: <554F5FFF12D4D311B04700508B5A9D2901C77402@HARSTONMAIL> The following was posted to CCD-world: > > I'd appreciate data, anecdotes, and pointers to where to find > out the real > story. > > Thanks, > > Phil Hobbs > IBM T. J. Watson Research Center > The normal white transfer compound used for power transistors is about 3w/mK and the tube claims is good down to -100C I have used this for peltier coolers to -30C. Apeizon vac grease is used in vacuum CCD cryostats but always manages to end up on the front surface by capillary action. Indium foil is good but only works when you can put a lot of pressure on the junction - it is good under heat straps. Underneath detector chips it just creates another junction making the transfer worse. The best tip is to be careful to thermally anchor the signal wires, it is possible to get more cooling into the device through the contacts than the package. Rockwell use this on their large format MCT arrays, there are 60 signal pins and 200 cooling pins connected to the substrates. Both Oxford instruments and Lakeshore have good descriptions of thermal epoxys and transfer compounds on their websites and catalogues. Martin Beckett ps. Did you write the Building Electro-Optical systems book? Dr Martin Beckett Scientific Generics Limited, Harston Mill, Harston, Cambridge CB2 5NH, UK Tel: +44 (0)1223 875 200 Fax: +44 (0)1223 875 201 email: mailto:mbeckett@scigen.co.uk - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From mac at astro.princeton.edu Fri Mar 16 08:01:35 2001 From: mac at astro.princeton.edu (Michael Carr) Date: Thu Jul 29 11:52:06 2004 Subject: CCD-world: Thermal Transfer Compounds References: <200103151837.NAA39542@sp1n189at0.watson.ibm.com> <3AB1E4B8.2C7E933B@obs-azur.fr> Message-ID: <3AB20EAF.1FFB794F@astro.princeton.edu> The best I have done is a delta T of -95C. (No load!) MICHAEL Alain Maury wrote: > > The following was posted to CCD-world: > > Don't stack your peltier yourselves, buy already assembled devices. > -100?C in a dry N2 atmosphere with Peltier coolers, huhhh.... good luck > ! > The best peltier cold boxes which I have seen are been built by Michael > Carr at Princeton, and they don't go that cold.... > Alain > > Phil Hobbs a ?crit : > > > > The following was posted to CCD-world: > > > > I've been investigating thermal transfer compounds, and man, is there a lot > > of snake oil being peddled out there. I've come across silver-loaded greases > > and epoxies that claim thermal conductivities from 1 to 60 W/m/K, as the silver > > content goes from 60% to 85%. > > > > Other people I've talked to have mentioned using indium solder paste cold, > > without reflowing it, but haven't done a lot of measurements of just how > > well it works. > > > > People also talk about interfacial thermal resistance, so that a plot of > > thermal resistance vs. grease thickness has a positive offset as the thickness > > goes to 0. > > > > I want to use stacked TECs to cool an infrared detector to about -100C in > > a dry nitrogen atmosphere, which is a stretch, and am clearly going to succeed > > or fail based on the thermal compound. > > > > I'd appreciate data, anecdotes, and pointers to where to find out the real > > story. > > > > Thanks, > > > > Phil Hobbs > > IBM T. J. Watson Research Center > > PO Box 218, > > Yorktown Heights NY 10598 > > > > - -- CCD-world -- -- > > CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk > > Standard replies will go to the list; address personal replies manually. > > For more information, please go to: http://www.not.iac.es/CCD-world/ > - -- CCD-world -- -- > CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk > Standard replies will go to the list; address personal replies manually. > For more information, please go to: http://www.not.iac.es/CCD-world/ -------------- next part -------------- A non-text attachment was scrubbed... Name: mac.vcf Type: text/x-vcard Size: 377 bytes Desc: Card for Michael Carr Url : http://www.ctio.noao.edu/pipermail/ccd-world/attachments/20010316/0fb7c54e/mac.vcf From rsmith at ctio.noao.edu Fri Mar 16 10:58:28 2001 From: rsmith at ctio.noao.edu (Roger Smith) Date: Thu Jul 29 11:52:06 2004 Subject: CCD-world: Thermal Transfer Compounds References: <200103151837.NAA39542@sp1n189at0.watson.ibm.com> Message-ID: <3AB22A14.A621B5A8@ctio.noao.edu> The following was posted to CCD-world: Phil, A long time ago I have read that studies in the low temperature physics community showed that the thermal resistance of clean Aluminium joints in vacuum is proportional to the force applied, and not the macroscopic area. The surface is rough at a microscopic level with effective contact area increasing as the peaks are deformed elastically. The job of the thermal contacting compound is to fill the microscopic voids and thus increase the area of contact. In your case, you are trying to fill those voids with a fluid that is more conductive than air. There is a lot to be gained by keeping the thickness of the contacting compound as small as possible. Ideally it would be limited by the surfaces flatness and finish. You should be able to make it thin enough that surface effects effect the performance more than the bulk conductivity. I haven't seen specs for such contact resistance effects for thermal contacting greases. Can anyone enlighten us? Greases designed for contacting hot components are usually extremely viscous making it difficult to achieve a very thin layer. This is not such a problem in transistor packages with heavy hold down bolts which can flow the compound, but is another matter with a delicate detector package. And of course high viscosity comes with the low vapour pressure of vacuum greases too, but they aren't as bad. If your detector package is bowed, you may need to grind your mounting surface to the mating shape! Roger Smith ---------------------------------------------------------------------- Engineering Project Manager 29.54 deg South, 71.16 deg West email: rsmith@ctio.noao.edu tel: 56-51-205200 fax: -205342 Cerro Tololo Inter-American Observatory, Casilla 603, La Serena, Chile Nat. Optical Astronomy Observatories,PO Box 26732,Tucson AZ 85726-6732 - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From tdroege at veriomail.com Fri Mar 16 09:02:58 2001 From: tdroege at veriomail.com (Tom Droege) Date: Thu Jul 29 11:52:06 2004 Subject: CCD-world: Thermal Transfer Compounds In-Reply-To: <3AB1E4B8.2C7E933B@obs-azur.fr> References: <200103151837.NAA39542@sp1n189at0.watson.ibm.com> Message-ID: <4.2.2.20010316075734.00b5fe50@pop.veriomail.com> The following was posted to CCD-world: I agree, -100 C sounds tough. I also agree that you should buy the stacks. Try www.melcor.com they have a large number of stacks available and notes that lecture you on why you should not try to make your own. Pay a lot of attention to the hot side. Good liquid cooling. I would start with anti-freeze at as cold as I could get it. -20 C might do it. Do the thermal computations on the hot side. I mill out the water channels to 1/16" thick behind the TEC face. You can easily lose a few degrees C from temperature drop through the aluminum behind the hot face. Don't even consider air cooling, there is just too much thermal drop out the fins. I have found that you have to circulate dry gas through the enclosure to avoid condensation problems. Much good advice from this group. Of course use vacuum if you can. BTW, if you are trying to control the temperature accurately, then make everything from silver. While it's thermal conductivity is not much different from copper, it's thermal capacity is much less, so one gains a factor of two in response time over copper and more over aluminum. If anyone cares, I have worked a lot on fast response of thermal systems and can give some hints on how to do it. Low cooling water temperature brings condensation problems. OK, I am not a big lab where you buy a chiller from Cole-Parmer when you need it. I buy a de-humidifier from Wall-Mart, bend it's coils into a bucket of anti-freeze, and stick a "Little Giant" pump in the bucket. This this costs much less and gets about 100 watts of cooling. It is all styrafoam and pipe covers from there. It is a matter of great controversy, but I recommend using thin PC boards to bring out the leads. You can make tiny strip lines on a pc board and avoid electronic signal problems. I cannot emphasize this too much. I have seen some detectors that are pretty awful from an electronic signal standpoint. Also, copper (the PC trace) has the best ratio of electrical conductivity (good) to thermal conductivity (bad) for bringing out a lead of any material that I have found. The real reason people use constantan and the like over copper is that an equivalent copper wire is fragile, and has high inductance. Epoxy has about 1/1000 the thermal conductivity of copper, so the board can be designed so that the copper is the dominant conductor. For the best source of thermal data I have found try http://www.tak2000.com/ They have a wonderful table you can download with every imaginable material in consistent units. I gave up on silver epoxy because it had always expired by the time I needed it. I now buy silver powder from Johnson Matthy, Aesar division, and mix my own when I need it. I use either epoxy or silicon grease and just load it up with silver when I mix it. Tom Droege At 06:02 AM 3/16/01 -0400, you wrote: >The following was posted to CCD-world: > >Don't stack your peltier yourselves, buy already assembled devices. >-100?C in a dry N2 atmosphere with Peltier coolers, huhhh.... good luck >! >The best peltier cold boxes which I have seen are been built by Michael >Carr at Princeton, and they don't go that cold.... >Alain - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From GregJ888 at aol.com Fri Mar 16 12:07:05 2001 From: GregJ888 at aol.com (GregJ888@aol.com) Date: Thu Jul 29 11:52:06 2004 Subject: CCD-world: Thermal Transfer Compounds Message-ID: <33.1217bea5.27e3a239@aol.com> The following was posted to CCD-world: You may also want to take a look at: http://www.advceramics.com/ I was given a sample of a Boron Nitride powder that I mixed with vacuum grease. Unfortunately I haven't tried it yet. From what I've seen it's not as good as silver, but much better that standard heat sink compound (ZnO). They also have some carbon materials that are unbelievable, if they fit the application. Hot side heat spreader maybe... Greg Jones - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From phil_hobbs at vnet.ibm.com Fri Mar 16 14:18:50 2001 From: phil_hobbs at vnet.ibm.com (Phil Hobbs) Date: Thu Jul 29 11:52:06 2004 Subject: CCD-world: Thermal transfer compounds Message-ID: <200103162004.PAA37428@sp1n189at0.watson.ibm.com> A non-text attachment was scrubbed... Name: not available Type: text Size: 3294 bytes Desc: not available Url : http://www.ctio.noao.edu/pipermail/ccd-world/attachments/20010316/6c011aa2/attachment.bat From mcba at phys.unsw.edu.au Sat Mar 17 12:52:45 2001 From: mcba at phys.unsw.edu.au (Michael C. B. Ashley) Date: Thu Jul 29 11:52:06 2004 Subject: CCD-world: Thermal Transfer Compounds In-Reply-To: <554F5FFF12D4D311B04700508B5A9D2901C77402@HARSTONMAIL> Message-ID: The following was posted to CCD-world: Ten years ago Brad Carter and I built a small Peltier-cooled CCD camera using a 4-stage cooler. We achieved a delta T of 113C, with a hot-side temperature of 24C (cold side -89C), while cooling a GEC P8603 (20x15mm area to be cooled). This required 30W of electrical power, which was extracted using liquid cooling. The system was in a vacuum. We did two interesting things: (1) We soldered the hot-side of the Peltier stack to the copper cooling chamber. We made the solder ourselves from indium and something else (I can't remember what ...), and designed its melting point to be 5 or 10 degrees below that of the solder used in the stack. The soldering was done by carefully heating the copper plate until the solder just melted. There was a nervous moment when the Peltier stack became somewhat soft, but it survived. (2) We built a small aluminium radiation shield and anchored it to the top of the second stage. This wrapped around the upper two stages and as much of the CCD as we could manage. It turned out to only make a 2.5C difference to the CCD temperature. The design was published in Proceedings of the Astronomical Society of Australia, Vol 9, pp158-159 (1991). I have placed the Postscript version of the text on http://www.phys.unsw.edu.au/~mcba/p032.ps (it doesn't include the figure, unfortunately). I believe that it may be possible to achieve better delta-Ts and heat-pumping capacity by careful specification of the number of junctions in each stage of the Peltier cooler. The ones that you buy commercially are not necessarily optimized for your application. Regards, Michael -- Michael Ashley; Department of Astrophysics, University of NSW; For further information: "finger mcba@newt.phys.unsw.edu.au" - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From jeff at 123jeff.com Fri Mar 16 23:18:44 2001 From: jeff at 123jeff.com (Jeff Thompson) Date: Thu Jul 29 11:52:06 2004 Subject: CCD-world: Thermal Transfer Compounds References: <200103151837.NAA39542@sp1n189at0.watson.ibm.com> Message-ID: <3AB2E5A4.41637110@123jeff.com> The following was posted to CCD-world: Hi Phil- I had to deal with this too many years ago for chilled radiometers in early thermal scanners. We are doing it again today. I guess the snake oil is just as rich now as then. We were trying to wring the last Deg-K out of our prototypes. We learned (probably re-discovered for the 497th time...) that the contact interface is essentially the mashing together of two mountainous landscapes. It was critical that the surfaces be of the identical figure (flat is simplest) so that uniform pressure is maintained across this interface without smashing your detectors, etc. We also found that the finer those 'mountains' were the better the thermal conductivity. Period, no question. Many a beer passed over the question of why more, smaller mountains were better than fewer, larger ones. A lot like today's debates over final density of a Cantor dust. Just smooth your surfaces as finely as possible. Remember, grind with water, wash in hydrocarbon (and vice versa) to avoid grit embedding. If you don't trapped abrasive will act as a stand-off and the conductivity will go DOWN. Final surface grinding is the key in my experience. Even if you are going to solder the surfaces. I like the 600 and 1200 grit diamond files and 'stones' by DMT. Machinists use them for lapping carbide, ceramic, etc. You can get them from Enco supply at www.use-enco.com for about 25 bucks. They work with water, so I use naphtha followed by MEK for final cleaning to remove ALL grit, finger oils, etc. from my pristine surfaces. Lap the TEC's, heat sinks, intermediate plates, cold finger ends, and don't forget the back of the chip package, too. It's critical that your thermal goo truly wet the surfaces such that it can help bridge the insulating air gaps between 'valleys' in your interface surfaces. As suggested elsewhere, wet the surfaces with your goo and wring them together to displace all air. The air has far worse thermal conductivity than the direct contact between the mountains of your surfaces or the goo in the valleys. We found it important to never reduce the wringing force. If you do it wrong, releasing the force will allow the joint to release and suck air. Then you start over. Right now we load the joints with goo, pre-fit nylon bolts between the plastic cold finger retainer saddle and the hot sink, start the parts together with a rocking motion to wedge out the air, then tighten slooowly and evenly while heating the whole stack with a hot air gun. The detector package is similarly treated with its retaining clips and nylon hold down screws. Never re-use the ejected and scraped off goo. It somehow gets loaded with dust and other crud and it will now act as an insulating spacer. Murphy. Today we can maintain about a 75 Deg-C difference with two TEC's in series (yeah, I did it myself. Next time, Melchor does it!). The cool end is an aluminum finger cooling a little TI TC-237 CCD. I needed to insulate the devil out of my cool box and my cold finger against both radiative and convective heating. Also, I use dry air to pre-infiltrate my test camera chamber. The chamber is aluminum insulated in polyamide epoxy resin really, really filled with glass micro-balloons (model aircraft hobby supplies). Next time, we'll use PVC to get away from the aluminum. A coat of the same epoxy mix is on the cold finger up to the chip mounting surface. Plain old Zinc Oxide grease has worked well. I tried silver loaded silicone greases 40 years ago and we had a problem with (we thought) oxides and sulfides of silver corrupting the soup and increasing insulating stand-off between the surfaces. I would like to hear any modern experience. Right now we're testing a sample of Bergquist's TC-7500. It seems better; in my prototype camera I can hit 75 to 79 Deg-C DeltaT with ease versus 68 to (stretch) 73 C with Radio Shack zinc grease. We are using water cooling for the hot side sink from a room ambient of about 20 C. The chip package at the cold finger interface is indicating about -47 C with the hot side of the TEC stack reading +30 C. Thanks Tom Droege for the hint to thin the hot sink behind the TEC for water cooling. Will do that tomorrow. Probably mill a new one with good support and turbulent flow against the hot wall. It has been a real long time since I fooled with TEC coolers and their relative inefficiencies. Analytical solution to the problem of extracting milliwatts of heat from a CCD by pumping with tens of watts in the TEC stack is subtle. The folks at Melchor.com have ton of references that make fascinating reading. They also have a nifty - and free - tool at their site called AzTEC for calculating power/ efficiency/heat flux/ Delta T in their TEC's. They offer prebuilt TEC stacks cheaply, too. We will use them for our product, believe me!! Jeff Thompson Phil Hobbs wrote: > The following was posted to CCD-world: > > I've been investigating thermal transfer compounds, and man, is there a lot > of snake oil being peddled out there. I've come across silver-loaded greases > and epoxies that claim thermal conductivities from 1 to 60 W/m/K, as the silver > content goes from 60% to 85%. > > Other people I've talked to have mentioned using indium solder paste cold, > without reflowing it, but haven't done a lot of measurements of just how > well it works. > > People also talk about interfacial thermal resistance, so that a plot of > thermal resistance vs. grease thickness has a positive offset as the thickness > goes to 0. > > I want to use stacked TECs to cool an infrared detector to about -100C in > a dry nitrogen atmosphere, which is a stretch, and am clearly going to succeed > or fail based on the thermal compound. > > I'd appreciate data, anecdotes, and pointers to where to find out the real > story. > > Thanks, > > Phil Hobbs > IBM T. J. Watson Research Center > PO Box 218, > Yorktown Heights NY 10598 > > - -- CCD-world -- -- > CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk > Standard replies will go to the list; address personal replies manually. > For more information, please go to: http://www.not.iac.es/CCD-world/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From ecw2f at wolfenet.com Tue Mar 20 10:45:52 2001 From: ecw2f at wolfenet.com (ecw2f) Date: Thu Jul 29 11:52:06 2004 Subject: CCD-world: Lapping Plates Message-ID: <003201c0b16d$fe7b02c0$d18c42cf@ECWELCH> Hi to All, Amazing how much I have learned from CCD World and the handy archives. I too have been dissapointed by heat transfer thru Peltier cooler interface plates. The discussion about the importance of lapping flat and avoiding embedding of abraisive reminds me of a technique used by an old time machinest. In lapping precision gears meshes he used fine powdered glass in a light oil or water vehicle. He found that it was much easier to remove the abraisive after lapping . Maybe this will work for interface plates. Regards, E. C, Welch -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.ctio.noao.edu/pipermail/ccd-world/attachments/20010320/de795f21/attachment.htm From tdroege at veriomail.com Wed Mar 21 04:56:08 2001 From: tdroege at veriomail.com (Tom Droege) Date: Thu Jul 29 11:52:06 2004 Subject: CCD-world: Thermal transfer compounds In-Reply-To: <200103162004.PAA37428@sp1n189at0.watson.ibm.com> Message-ID: <4.2.2.20010321035937.00ca85f0@pop.veriomail.com> The following was posted to CCD-world: Hello Phil, I would like to discourage you from making your own stack. My experience is that more is lost in any spreader than you might gain. You will have two more surfaces per section to get right. Sounds tough to me. I assume you have done computations on the lateral heat transfer and are convinced that you can improve it. I suppose it depends on what facilities you have. One could possibly make better spreader plates if you assemble your own stacks from junctions. On the topic of transient response. I struggled with this for some time when building my calorimeter for doing "Cold Fusion" work. Relax, I am not a total nut case. In the end I was able to hold a heat balance to of order 1 mw in a 10 watt calorimeter over months. I ended up debunking every "excess energy" claim that came my way. Garwin at IBM was most helpful and supportive. It is no fun being a debunker, so I have moved to astronomy. The problem with the long time constants of such devices is measuring the transfer function. Once you have that, then the control loop can do what it can do. Doing things in the frequency domain is impossible. It can take days to measure the response at one frequency when it is microhertz. The way I got around this was to put thermometers (tiny thermisters) on the hot and cold side, and roughly close the loop. Now one takes data points over time at the input and output and uses the fft to go to the frequency domain. Divide the output by the input and out pops the device transfer function. For my calorimeter I recall the first pole was at 20 microhertz or so. Once you have this you can usually close a linear control loop with some reactance graph paper and a couple of resistors and capacitors. For the Mark III telescopes I was able to hold to 0.001 C rms in the lab. This deteriorated to 0.01 C in the field. This with 20 C water and a two stage cooler operating from -20 to -30 C. The tight control was not needed but fun to do. This used a standard PI (proportional integral) loop, but the parts values got rather large. I recall 100 uf and 100 megs in the FB loop. I know most of you will want to do this with a DSP these days. To me they are noise sources. There are great analog amplifiers available these days for such things. Reading before sending I just realized what you are saying here: >The point about silver producing a 2:1 speed advantage over copper and >even more over aluminum due to its low cP is also a good one. The >transient response of a stack is not pretty, and anything that helps >would be great. The ugly transient response typically makes you use a >fixed drive current and a resistor on the cold plate to get accurate >temperature control, which is wasteful since every milliwatt >dissipated there grows a good deal before reaching the heatsink. The >same goes *a fortiori* about the leads. This seems really ugly to me! You sure don't want to heat the final stage. OK, it may take 1/2 hour to get there, but I think you can control the final stage to 0.01 C or so if you try without a heater. I assume that you do not have a big pulsed heat load on the final stage. The heat losses help stabilize the system. This assumes a linear control system. Just a power amplifier driving the hot side, and a good integrating amplifier. It helps if you don't have to close the loop over a wide range as these systems are far from linear. I assume you are just trying to control around "as cold as you can get". Remember that TECs drive both ways so use a power amplifier that is bipolar. It makes it easier to control the system. This is also handy to heat the final stage to outgass it or defrost it. Tom Droege At 02:18 PM 3/16/01 -0500, you wrote: >The following was posted to CCD-world: > >Thanks to everybody who responded--your comments are very illuminating. > >I am indeed planning to make my own stacks, because the commercial >ones don't have aluminum spreader plates in between sections--they've >got junctions soldered to the top and bottom of a single piece of >alumina. The problem with this is enormous lateral temperature >gradients, so the junctions near the periphery of the lower stage >contribute almost nothing to the cooling--not much heat is going to >travel edgeways through 1 cm of 0.5 mm thick alumina. This limits the >delta-T of the module severely, since you can't increase the effective >area of the lower stages fast enough to compensate for the inefficiency >of the upper ones. > >I've done some modelling that seems to suggest that -100C is not >impossible, provided (as you say) that I don't let the heatsink get >warm--polycrystalline bismuth telluride TECs are at their best near room >temperature, so I don't gain a whole degree at the cold finger for every >degree at the heatsink, but it's close. Some new cesium bismuth telluride >devices (not commercial yet, unfortunately) have their maximum figure of merit >at -70C, which will help. > >The advice to lap the surfaces together to reduce the height of >the grease layer is excellent--I've done this in the past, and it >makes a big difference. > >The point about silver producing a 2:1 speed advantage over copper and >even more over aluminum due to its low cP is also a good one. The >transient response of a stack is not pretty, and anything that helps >would be great. The ugly transient response typically makes you use a >fixed drive current and a resistor on the cold plate to get accurate >temperature control, which is wasteful since every milliwatt >dissipated there grows a good deal before reaching the heatsink. The >same goes *a fortiori* about the leads. I'm using a single element >InAs detector, which requires a lot fewer leads to the cold plate than >your average CCD, but the TEC leads are certainly a problem. Copper >wins in electrical-to-thermal conductivity ratio, but one has to >choose the length and diameter of the wire correctly, with the power >dissipation about equalling the thermal conduction. > >The thermal conductivity of a dry joint being proportional to the >normal force is what one would expect from the usual Hertzian model of >contact area--that the total microscopic contact area in a joint is >equal to the normal force divided by the yield strength of the >material. Since copper has 10**4 times the thermal conductivity of >air, this matters a lot. I'm less clear on what happens when the >two materials are different, or when one of them is a suspension rather >than a solid. > >I've read about those oriented carbon fibre tapes--carbon fibre's >alpha is around 500 W/m/K along the fibre axis, and the self-adhesive >tapes are claimed to reach 100, which is very good. The problem is >that they don't seem to be standard products. > >Thanks again, > >Phil Hobbs >IBM T. J. Watson Research Center >Yorktown Heights NY 10598 > > >- -- CCD-world -- -- >CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk >Standard replies will go to the list; address personal replies manually. >For more information, please go to: http://www.not.iac.es/CCD-world/ - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From mcba at phys.unsw.edu.au Fri Mar 30 12:08:53 2001 From: mcba at phys.unsw.edu.au (Michael C. B. Ashley) Date: Thu Jul 29 11:52:06 2004 Subject: CCD-world: Intra-pixel sensitivity variations In-Reply-To: <3A9E6563.1052@nasw.org> Message-ID: The following was posted to CCD-world: Dear gurus, I am interested in intra-pixel CCD variations, and how they affect photometry and astrometry of stars. In 1994, Paul Jorden, J-M Deltorn and A.P. Oates reported some results (RGO preprint 186; SPIE vol. 2198) obtained by scanning an EEV device with a sub-pixel light source. A student and I are attempting similar measurements with our front-illuminated EEV chip. I have a few questions for this group: - With some knowledge of the structure of the CCD (e.g., electrode positions/widths) would it be practical to produce a theoretical model of the expected intra-pixel variations? - Our telescope has an f/1 beam. This will presumably alter the observed intra-pixel variations, particularly at the red end where photons have a longer penetration depth. These photons may be absorbed in a neighbouring pixel if they strike the CCD at a large angle. Is it reasonable to attempt to calculate the effect of f/# and wavelength on intra-pixel response using a simple model of a pixel and a knowledge of penetration depth as a function of wavelength? - With a three-phase CCD, the intra-pixel response is likely to depend on which of the phases is used to collect electrons. Has any work been done on this? Some of the (very-limited) work that has been done on intra-pixel variations appears to have used lasers or LEDs. We wish to use white light and standard astronomical filters to more closely match the observations. Any and all suggestions gratefully received, regards, Michael -- A/Prof. Michael Ashley; Department of Astrophysics, University of NSW; For further information: "finger mcba@newt.phys.unsw.edu.au" - -- CCD-world -- -- CCD-world is fully moderated. Send posts to CCD-world@astro.ku.dk Standard replies will go to the list; address personal replies manually. For more information, please go to: http://www.not.iac.es/CCD-world/ From gordon_hopkinson at siraeo.co.uk Fri Mar 30 10:54:10 2001 From: gordon_hopkinson at siraeo.co.uk (Hopkinson, Gordon) Date: Thu Jul 29 11:52:07 2004 Subject: CCD-world: Intra-pixel sensitivity variations Message-ID: <9D70BF372E81D2119C3900609769B49F1E8C39@siraeo.demon.co.uk> The following was posted to CCD-world: Dear All Many (nearly 15!) years ago we did some spot scans of EEV chips at about 1 micron resolution and could see the intra-pixel response quite easily. In a cross electrode scan the profiles do indeed depend on which phases you are using but the sum is always the same - dividing the signal between pixels is essentially a lossless process - so you should get the same total star brightness regardless of what electrodes you choose to integrate under. Provided you have a good translation stage, an optical spot measurement is not very difficult and you can filter the light to simulate any star spectrum. Best Regards Gordon Hopkinson _______________________________ Dr G R Hopkinson Sira Electro-Optics Ltd South Hill Chislehurst Kent BR7 5EH UK Tel. +44 (0)20 8467 2636 Fax. +44 (0)20 8467 6515 E-mail: gordon_hopkinson@siraeo.co.uk http://www.siraeo.co.uk ___________________________________________________________ This message and any attachments is for the intended addressee only. Please contact us immediately if you have received this transmission in error. If you are not the intended recipient, you should note that any use, copying, disclosure or distribution of this information is strictly prohibited. The views of the author may not necessarily constitute the views of Sira Electro-Optics Ltd. Nothing in this email shall bind Sira Electro-Optics Ltd in any contract or obligation. _________________________________________________________ > -----Original Message----- > From: Michael C. B. Ashley [SMTP:mcba@phys.unsw.edu.au] > Sent: 30 March 2001 03:09 > To: CCD-world@astro.ku.dk > Subject: CCD-world: Intra-pixel sensitivity variations > > The following was posted to CCD-world: > > Dear gurus, > > I am interested in intra-pixel CCD variations, and how they affect > photometry and astrometry of stars. > > In 1994, Paul Jorden, J-M Deltorn and A.P. Oates reported some results > (RGO preprint 186; SPIE vol. 2198) obtained by scanning an EEV device with > a sub-pixel light source. > > A student and I are attempting similar measurements with our > front-illuminated EEV chip. > > I have a few questions for this group: > > - With some knowledge of the structure of the CCD (e.g., electrode > positions/widths) would it be practical to produce a theoretical > model of the expected intra-pixel variations? > > - Our telescope has an f/1 beam. This will presumably alter the >