Static Characteristic Test And Neutron Detection Performance Of SiC Neutron Detector

SiC has been recently proposed in alternative to silicon in semiconductor-based radiation detectors.The higher band gap energy and greater displacement threshold energy of 4H-SiC should theoretically lead to neutron detectors made of 4H-SiC capable of operating at elevated temperatures and in high radiation fields.However,studies on neutron detectors made of 4H-SiC have just been prompted for the last decade,properties of 4H-SiC neutron detectors need to be systematically addressed.In this paper,the performance of silicon carbide neutron detector is studied.This paper first introduces the principle and method of neutron detection and spectrum test.The reaction mechanism between neutron and semiconductor is briefly described and the main factors affecting the performance of semiconductor detector are analyzed.According to the influence factors of detector's performance,the reverse leakage current characteristic and C-V characteristic are tested.The reverse leakage current characteristic test results show that in 200V applied reverse voltage leakage current is only 0.95nA.In order to solve the problems that traditional impedance analyzer is not applicable to the semiconductor detector C-V characteristics testing,a kind of C-V characteristic test method based on the lock-in amplifier was proposed,using discrete components to build the test system,which greatly reduces the cost of testing.The accuracy of the system is verified by using the nominal capacitance,and the measurement error is less than 10%.Detector capacitance test results show that the relationship between capacitance and size is in accordance with the proportion.The linearity fitness of1/C²-V is up to 0.99.The depletion voltage is 100V,and the doping concentration is 10¹⁵/cm³.Energy calibration of detectors with different sizes was carried out using a test system builted for the measurement of the incident particle energy spectrum.After the energy calibration,a single energy neutron source is used to illuminate the detector.The detection efficiency of the detector is 5×10^-5,and the measured energy spectrum is consistent with the theoretical results.The different conditions of the detector spectral measurement results show that:Before the full depletion of the detector,the increase of bias voltage can make the detector have larger sensitive volume and thus improve the detection efficiency of the detector.The capacitance and sensitive volume of the detector will increase with the enlargeing of its size.Larger sensitive volume will improve the detection efficiency,conversely large capaciance will deteriorate the energy resolution of the detector.