Shielding in radiation safety means attenuation to a safe level. But for detection, that is irrelevant because radiation detectors can be very sensitive, such t

Shielding in radiation safety means attenuation to a safe level. But for detection, that is irrelevant because radiation detectors can be very sensitive, such that even very minute quantities making it through a "shielding" are still sufficient. When in doubt, you just increase integration time to almost forever and you will still get a sufficient number of particles to get a measurement.