An area radiation monitoring system for nuclear plants using PIN photodiodes

An area radiation monitoring system was designed using the solid state technology replacing the traditional GM tubes. Unlike the GM tubes, PIN silicon photodiodes require relative low bias voltage, have smaller detector size, respond more linearly to radiation, and are capable detecting wider radiation range. A microprocessor is also incorporated in this design to enable the operator to screen out unwanted low energy gamma rays, and an electronic bug source is also used to eliminate a possible down scale trips from statistical uncertainty from radioactive bug source and background radiation. This system is currently installed through out the nuclear plants to monitor radiation levels