Re: Effects of Radiation on Electronic Equipment

["Michael P. Grissom" <mikeg@SLAC.Stanford.EDU>]

Re Roger's reply on this subject,

This issue (which has traditionally been considered in 
the general category of "Rad Hard") regarding the 
effects of krad and megarad doses on electronic and
other material components is relevant and should be 
carefully considered by those dependent on electronic 
control systems, such as accelerators, reactors, and 
large sealed source irradiation facilities.

Besides Roger's note about oil polymerization, there
was recent discussion on radsafe about the effectiveness 
of Teflon based cable liners.  We have observed that 
after several mrads of exposure (such as may be observed
near high power dumps and collimators/slits in accelerator
systems), the Teflon jacket embrittles.  In one instance
where a cable had been in place for a long time, the dose 
received had been sufficient to reduce the Teflon to a 
brown friable powder, that literally poured out of the 
cable when cut!

With regards to the discussion of background radiation
effects on computers, a paper was presented at the Boston
meeting of the HPS in June 1995 regarding naturally
occurring radionuclide effects on the computer industry.
It was noted that high density disk drives using ceramics 
had some problems with thorium (in fact some drives in the 
early days intentionally were doped with-I think-thorium or
radium).  The main problems noted in the paper, however, 
were in chip production.  High failure rates were linked to 
using materials with elevated levels of naturally occurring 
radionuclides.  Sorting stock materials reduced failure 
rates to acceptable industry levels.  DRAM and ASICs were 
mentioned.  Perhaps someone at the recent NORM topical
symposium can add to this?

Hope this is of some help,

MikeG.

At 10:05 AM 2/21/96 -0600, you wrote:
>Radiation Effects on Electronic Equipment
>     ...
>I am also aware of anecdotal examples of radiation damage causing
>problems, e.g., with a robot designed for automated retrieval and
>transfer of targets to a shielded container on a cart for
>transport to a hot cell; this occurred at a radionuclide
>production facility.  At high doses, other, unexpected effects can
>occur on non-electronic components, e.g., the polymerization of
>oils on rods used to move sealed sources in self-contained
>irradiators.
-----------------------
Michael P. Grissom
mikeg@slac.stanford.edu
Phone:  (415) 926-2346
Fax:    (415) 926-3030