In case you didn't read it, here is an interesting article about the subject:

http://pages.uoregon.edu/joe/infragard-2009/infragard-eugene-2009.pdf

It made me remember of the days when I was in the Navy, on a very old ship, and most of our electronic equipment was on vacuum tubes not on semiconductors. Our technicians were proud that our ship was immune to the atomic bomb radiations