Archived posting to the Leica Users Group, 2003/10/08

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Subject: RE: [Leica] Re:[leica] Recent Airport Experience with Bulk film
From: "Saganich, Christopher/Medical Physics" <saganicc@MSKCC.ORG>
Date: Wed, 8 Oct 2003 17:00:56 -0400

Adam, demanding aren't we.  Send me some gear and 4-6 years worth of grant money and I'll answer all your questions.  

In the meantime we know that protons from 10-100 MeV will damage electronic equipment in space, (Ref: Nasa).  We know that Solid state devices (transistors and integrated circuits) are particularly sensitive to high radiation doses of 10 Gy or 1000 Rads.  (Ref: NCRP Report No.88, "Radiation Alarms and Control Systems"). We know that High failure rates in "chip" production were linked to using materials with elevated levels of naturally occurring radionuclides, (Ref:  HPS paper, June 1995, "Naturally occurring radionuclide effects on the computer industry".)

The satellite industry does a lot of research in this area, check out:

http://www.aero.org/publications/crosslink/summer2003/06.html

will answer some of your questions.

The question remains if lower levels of radiation such as from a small X-Ray unit will damage electronic equipment.  The rule of thumb for all radiation based effects is "Linear no threshold" which means  if a lot of radiation caused a lot of damage then a little causes a little damage.

Chris Saganich


- -----Original Message-----
From: owner-leica-users@mejac.palo-alto.ca.us [mailto:owner-leica-users@mejac.palo-alto.ca.us] On Behalf Of Adam Bridge
Sent: Wednesday, October 08, 2003 3:40 PM
To: leica-users@mejac.palo-alto.ca.us
Subject: Re: [Leica] Re:[leica] Recent Airport Experience with Bulk film

On 2003-10-08 saganicc@MSKCC.ORG (Saganich, Christopher/Medical Physics)
thoughtfully wrote: 

I would like demonstrable proof that X-rays of the intensity used in checking
your hand-held luggage in airports will cause malfunctions or degradation of
electronic equipment.

Chapter and verse please.

Is it causing impurities to migrate across junction boundaries? If so what
amount X-Ray will cause this to happen. Is it playing Hobb with semi-conductor
field effect transistors? How? Messing with capacitors? How.

Heck - maybe it's exposure to gamma while at high altitudes and not the x-rays
that would cause equipment problems in long high-altitude aircraft flights.

Adam
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