Low-Background Measurements of super(22)Na in Natural Waters of Krasnodar Krai

Gamma spectrometers with 100 100 mm NaI(Tl) and 200 100 mm CsI(Tl) crystals for detecting annihilation radiation of b super(+) radionuclides are described. Two spectrometers are located in a surface laboratory and one underground, at a depth of 500 m of water equivalent, in Novorossiisk. The background characteristics and the detection efficiency are presented for different operating modes of the coincidence system and for samples with different mass. A coincidence scheme in which all events with coincidences of pulses in both crystals and energy released in each detector are detected, making it possible to raise the super(22)Na detection efficiency by approximately 30%, was tested. The results of measurements of the super(22)Na content in some natural waters in Krasnodar krai, including in mud volcanoes, are presented. They show large seasonal variations.