A low-cost instrumentation for monitoring of the environmental radioactivity

Abstract

In this work, a low-cost radiation monitoring instrumentation for measuring the environmental gamma radioactivity together with some atmospheric parameters was designed and produced. The device has been built with market available components. The detector section of the device uses a Si-PIN photo-diode as an active element. A tiny current produced from the energy deposition of gamma rays in silicon is amplified in two stages, firstly with a charge sensitive amplifier (CSA) and secondly with a shaping amplifier (SA). The amplified signal is further processed to be converted into digital pulses for counting. The monitor station is designed to be operated remotely in self-sufficient mode, equipped with LoRA module running at 500 MHz to transfer the data remotely to a base station. The base station also includes a LoRA module to receive the data and stores it in an SD card while an OLED display visualizes the recent measurement. Multiple monitor stations can be used to control the radioactivity level in a field simultaneously. This field could be used inside or outside of an interested facility. The noise limit of the detector developed was determined to be as low as 20 keV photon energy. The low-energy detection limit was conservatively set to 40 keV which was still below the 64 keV of the naturally occurring 234Th. Counting the events for hourly, daily or weekly provide statistically significant data depending on the activity of the interested region. All gamma energies above 40 keV from the decays of naturally occurring radioisotopes can be practically observed with this device. The anomalies can be detected using various mathematical algorithms that can be embedded into the microprocessor and the results can be shared with the public.