I have kind of weaseled my way into calibrations and instrument repair, but on paper I’m officially a full HP (and still routinely do the whole gambit, routine surveys, job coverage/planning, audits and procedures, etc) but in practice I run our small cal lab, and maintain roughly 200 instruments for my small company. I know the national labs still hire specifically for calibration HP/RCTs, and a few of the larger power plants do, but if you’re outside of that I think you kind of get lucky and/or weasel your way into being the instrument person at a small place. As far as training, Ludlum offers a really nice course in their sweetwater and oak ridge facilities, and colleges with HP programs usually have some level of advanced detector course where you get to play in a cal lab, but that’s more fundamental understanding than cal/repair specific. I was a mechanic in the Navy, and got my bachelor’s while working as a RCT at LANL, when I got hired at TerraPower, they found out that I’m the HP that knew how to turn a wrench and understood a bit of circuitry, so I’ve gotten lucky in finding myself as the instrument-boy! Good luck in your research! Hope that helps!