camera calibration

[Gerard Luppino]

Hi Paul,

Just to clarify your message, if you are using Fe55 x-rays,
you don't need a "thin" Be window. I've used windows with
thicknesses from 0.1mm up to 0.5mm! The 0.5mm is a pretty
strong hunk of metal and can span a rather large (10mm or more)
hole and not have any problems withstanding vacuum. You can
get Be pretty cheaply in the thicker sizes and can make a mesh
frame that allows you to make a Be window large enough for
a big focal plane. Also, The thicker Be is totally opaque to optical
light (well, so is 0.1mm Be). Users should beware of the hazards
of workking with Be, however. Be dust is pretty nasty stuff.
The material should not be cut or machined without the proper
precautions and equipment.

Aloha,

Gerry