Research On ??? Low-background Monitoring Device Based On PIPS

As an important part of the radiation monitoring network, environmental radioactivity monitoring is concerned with the safety of people's living environment.And the low background monitoring device can effectively measure the soil, water,and aerosol in the environment, and to evaluate the level of environmental radioactivity by measuring the activity of alpha and beta. At present, the main low background monitoring instruments mainly uses double plastic scintillant as the main detector, Considering the economy and rapid response ability, but because of its poor energy resolution, in the energy spectrum analysis the interference of radon and thorium is very serious, this will be easy to cause high false counts. Therefore, the development of a new type of low background alpha and beta activity monitoring device is an important direction of the current radiation detector.Aim at eliminating interference of the radon and thorium progeny, this paper raised a device measuring ??? based on the PIPS,because the energy resolution of the PIPS is better than other types of detectors. In the energy spectrum, we can distinguish between the artificial radionuclides and the radon and thorium interference.In the design stage, using Monte Carlo program to simulate the detection method,the detection efficiency and environmental gamma background effect, It provides an important theoretical basis for prototype manufacturing equipment. The results show that the end-face measurement is better than the well-type, and plastic scintillator has better detection efficiency and can effectively improve the anti-coincidence; and to simulate environmental radioactivity, the lead shielding with thickness of 5cm can effectively shield the 1.332MeV energy gamma background, reduce the interference of environmental background radiation; at the same time the results indicate that the PIPS as main detector combined with spectrum stripping software, can effectively isolate the radon and thorium progeny and artificial radionuclides in the program and try to control the high count that introduced by radon and thorium progeny. The circuit of the monitoring device is designed with two channels. The isolation design of the plastic scintillation detector and the PIPS detector was also be taken into acount.The circuit and the detector are built in the lead chamber. The signal is connected to the LPDU by the transmission cable. The manufacturing prototype is proved to be effective, and efficiency calibration, cross track and detection limit measurement test show that the design of the device has a certain reliability.