speaking of protons...
https://www.quantamagazine.org/physicists-finally-nail-the-protons-size-and-hope-dies-20190911/
I know a materials scientist at Larry Livermore, but nobody in fab work. If you think he might be able to help you (say find a machining operation) LMK and I'll pm his name. He may have retired by now anyway. Or he could be in permanent physical therapy for having dozens of tags hanging around his neck all the time...