Radiation monitoring system using a PIN photodiode at the KEK electron/positron injector LINAC

We have been developing a real-time radiation monitoring system based on a PIN photodiode gamma ray detector (developed by Taisei Corporation, manufactured by Yaguchi Electric Co., Ltd., originally designed by Radiation-Watch Co., Ltd.,PocketGeiger(TM)). This compact and portable system consists of a small sensor unit and a Raspberry Pi, with control software developed using an EPICS-based framework. The software is designed to support a wide range of radiation measurements. To evaluate the system's measurement accuracy and reproducibility, the sensor was calibrated with Co-60 and Cs-137 sources at the KEK Radiation Irradiation Facility. In addition, radiation measurements were conducted during both operational and shutdown periods of the KEK electron/positron injector LINAC. This paper presents a detailed description of the system and its control software, along with the results of calibration and measurement tests carried out at the facility.