IAEA-MELʹs underground counting laboratory in Monaco—background characteristics of HPGe detectors with anti-cosmic shielding

The background characteristics of large volume HPGe detectors installed in IAEA-MELʹs underground counting laboratory situated at a depth of 35 m water equivalent have been investigated. Both single gamma-ray spectra as well as gamma-ray spectra gated by anti-cosmic shielding made of plastic scintillators are presented. The advantages of anti-cosmic shielding for HPGe detectors, especially in underground counting laboratories operating at shallow depths, are discussed. The authors present several examples of analysis of radionuclides in marine samples by single gamma-ray spectrometers with anti-cosmic shielding, an anti-Compton spectrometer and a Ge–Ge telescope designed for the analysis of low energy gamma-emitters.