There were a lot of these kinds of tests, particularly with testing of the new H-Bombs. My dad got sent over there for some time, we never really heard about what he did, but in his gear when he came back were a bunch of these on chains he wore while there:
http://www.orau.org/ptp/collection/radiac/DT60.htm
You can see in some movie accounts where the ships were boarded and inspected immediately afterwards. In one movie, scientists that were there with radiometers saw the extent and boogied out.
Years later he developed a lot of medical problems and had to be medically retired. My mom fought for years with the VA over causes. It got to the point they said “Prove he was there.” He didn’t save copies of the orders and he wasn’t on a set of orders that would be catalogued by his name only.
After years researching and snail mail correspondence with other veterans, relatives, etc. she go a set of orders where his name appeared along with a few dozen others.
Eniwetok I remember him saying, but that’s pretty much all he did say. He ended up on 100% service-connected disability and died about 20 years after he was there.