. We report on the design and construction of an Early Warning Environmental Radiation Monitoring Station (EWERMS), used ONLINE in the environmental radiation monitoring and early warning network. It has a high sensitivity and can send a prompt alarm signal via Internet to the emergency management office. It includes four gamma probes: one NaI(Tl) and three Geiger Mueller (GM) detectors. The NaI(TL) detector is used to monitor spectrum environmental radiation and measure the isotopic composition, the GM detectors are used to detect and measure high gamma ray rates. | Communications in Physics, Vol. 22, No. 4 (2012), pp. 375-382 STUDY, DESIGN AND CONSTRUCTION OF AN EARLY WARNING ENVIRONMENTAL RADIATION MONITORING STATION DANG QUANG THIEU, TRAN NGOC TOAN, NGUYEN THI BAO MY, NGUYEN VAN SY, VU VAN TIEN, NGUYEN THI THUY MAI AND LE DINH CUONG Institute for Nuclear Science and Technology, Vietnam Atomic Engergy Institute Abstract. We report on the design and construction of an Early Warning Environmental Radiation Monitoring Station (EWERMS), used ONLINE in the environmental radiation monitoring and early warning network. It has a high sensitivity and can send a prompt alarm signal via Internet to the emergency management office. It includes four gamma probes: one NaI(Tl) and three Geiger Mueller (GM) detectors. The NaI(TL) detector is used to monitor spectrum environmental radiation and measure the isotopic composition, the GM detectors are used to detect and measure high gamma ray rates. The instrument has been designed to be used outdoor and tolerate large and rapid temperature variations. The photomultiplier tubes (PMT), amplifiers and Analog To Digital (ADC) gains are stabilized using pulsed LEDs as precision reference light sources. I. INTRODUCTION More and more nuclear reactors are being constructed and operated worldwide for the purpose of power generation as well as for doing research. Consequently, continuous monitoring of the ambient dose rate is an essential task that must be carried out routinely in order to provide the responsible radiation protection governmental authorities with the necessary information. This includes: a) establishing a national data base of environmental dose rates covering the whole country; b) in a preliminary phase, measuring and recording baseline background gamma radiation levels to be used as a reference for future surveys; c) providing an early warning alarm in case of an important increase of the radioactivity level. This requires the installation and operation of an array of radiation .
