A large volume low-level detector for measuring the gamma-radioactivity in water

The main features of a low-level large-volume detector for measuring in real time the gamma -radioactivity in water are described. The detector is made of plastic scintillators interleaved with Pb converters. A particular geometry allowing an efficient rejection of the background due to cosmic rays is adopted. The detector is able to operate submerged up to 30 m and has a sensitivity level of 10/sup -3/ Bq/ml.<
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