An in-situ gamma-ray spectrometer for the deep ocean

A low resolution subsea gamma-ray spectrometer is developed for monitoring radioactivity in the deep ocean. The detection system provides quantitative results combining experimental and simulated data. The system is tested for pressures up to 456 105 Pa and is demonstrated in the deep sea South of Crete (Greece) at a depth of 2700 m. The minimum detectable activity for 214Bi considering a 7200 s measurement, was found 0.3 Bq/L due to the extremely low background contribution at high energies.