Path: utzoo!utgpu!water!watmath!clyde!rutgers!iuvax!pur-ee!uiucdcs!uxc.cso.uiuc.edu!uxe.cso.uiuc.edu!mcdonald
From: mcdonald@uxe.cso.uiuc.edu
Newsgroups: comp.sys.ibm.pc
Subject: Re: Laptops and Airport Security
Message-ID: <45900107@uxe.cso.uiuc.edu>
Date: 26 Jan 88 15:49:00 GMT
References: <4426@garfield.UUCP>
Lines: 15
Nf-ID: #R:garfield.UUCP:4426:uxe.cso.uiuc.edu:45900107:000:835
Nf-From: uxe.cso.uiuc.edu!mcdonald    Jan 26 09:49:00 1988


I have not verified this, but it seems likely that x-rays could damage
the information on UV erasable programmable ROM chips. These things work
by permanently storing a small charge. The UV light generates charge carriers
in such a way as to discharge the capacitors?/diodes? which hold the charge.
X-rays would generate exactly the same kind of charge carriers. The major
question is whether one hit would discharge a cell. It takes lots of
UV hits to do it, but one X-ray is worth a lot of UV photons.
   Many computers contain UVEPROMs, for example the XT I'm typing this on
as well as a friend's PC Portable.
   One X-ray hit will absolutely render a grain of film developable; therefore
NO X-ray machine is completely safe for any film. The only difference
is that only high speed film will be ruined by one X-ray.

DougMcDonald