Thermal neutron detector based on BNCT beam monitoring: conceptual design and readout electronics measurement

Beam monitoring and evaluation are very important to boron neutron capture therapy (BNCT), and a variety of detectors have been developed for these applications. In this study, a method of position sensitive neutron detector based on evaporated solid neutron conversion layer is proposed and designed, and the structure design and working gas optimization of the detector are carried out by Monte Carlo method. The related hardware design of readout electronics for neutron detector is completed, and the electronic performance test is carried out. The results show that the thickness of the neutron conversion layer is the best when the thickness of the neutron conversion layer is 2 μm. At the same time, the aluminum layer coated with 2 μm after the neutron conversion layer can effectively reduce the most probable angle of the emitted particles, and Ar: CO2 (90: 10) is used as the working gas. The front-end readout electronics can meet the bipolar signal processing of 64 channels in the dynamic range of 120 fC ∼10 pC at the sampling frequency of 1–100 MHz. The set of electronic system has high integration, low noise, low power, and can quickly process multi-channel signals. The integral nonlinearity is less than 1.5 %, which can meet the requirements of real-time online monitoring neutron detectors of BNCT. It is evident that this ionization-based neutron detector with multichannel and high counting rate capability has great development prospects dose monitoring and evaluation applications in BNCT.