I've worked as an engineer for the last 14 years for two nuclear thickness gauge companies, four if you count the name changes the first went through
having fun playing with and designing various isotope and x-ray sources, detectors, and so on. Thickness gauges basically measure the attenuation of a beam of radiation through a material to measure how thick it is (though there are other techniques we use as well, such as backscatter and fluorescence).My primary interests now are designing and building various radiation detectors. I have some simple GM tube units that I sell on the side, which plug into a PC USB or serial port for datalogging, as well. I'd like to try my hands at building an MCA system next, having been able to use some in the past. I was most impressed with the Amtek units I played with, they had x-ray resolution of around 200 eV, very cool to be able to fluoresce a piece of stainless and not only see the Fe, Cr, Ni, etc lines, but separate the Ka and Kb as well!