Groundwater, radon continuous monitoring system (alpha-scintillation counting) for natural hazard surveillance

A "quasi continuous mode" monitoring system to measure the radon concentrat ion within a natural environment (mainly groundwater), was designed, assemb led and tested, under collaboration between DINCE and ING, partly within th e framework of two EC funded programs. The radon monitor consists of a customised discrete automatic sampler which produces a gas flux circuit, and an economical a-scintillation cell, coupl ed with a reliable electronics-photomultiplier assemblage. A convenient cal ibration system together with a temporised control system have been set up. The overall "mean efficiency" of the system was calculated to be 7.79 +/- 0.13 counts per minute (cpm) for each Bq/L. Taking into consideration the present and future requirements of a geochemi cal surveillance network to assess natural hazards, the prototype design ev olved from the study of existing systems devoted to monitor radon concentra tion levels, which are critically reviewed within this paper. In response to the main prerequisite of a remote station: maximum remote se nsor versatility preserving shared software and hardware for the network as a whole, this radon monitoring system was conceived as part of a multi-par ametric Geochemical Monitoring System (GMS II) prototype, designed and real ised as a test-stand for sensors (chemical, hydrological, geophysical, orga nic chemistry devoted, etc.) in continuous evolution throughout the interna tional market.