GMON, A NEW SENSOR FOR SNOW WATER EQUIVALENT VIA GAMMA MONITORING

Abstract

GMON is a Gamma MONitor that measures the absorption of the natural gamma radiation through the snow cover and reports the snow water equivalent (SWE) for a large ground area typically of 100 m 2 by tracking the number of hits recorded on a daily basis from potassium ( 40 K) and thallium ( 208 Tl) energy windows respectively located at 1.46 MeV and 2.61 MeV. The sensor element is a conventional thallium doped sodium iodide scintillator NaI(Tl) coupled to custom electronics both embedded in an aluminium housing containing high performance insulating material preventing thermal shock damage when the sensor is exposed to -40°C.