Clover Detector Efficiency Calibration

HPGe detector, of which the energy resolution is much better than the normally used NaI(Tl) detector, is widly used to detect theγ-ray. The HPGe detector can distinguish two spectrums of which the difference between the two energy information is not distinct. Therefor, the Ge detector is applied to most researches related to complexγ-ray spectrum.The Clover detector which contains four HPGe crystals has superiority in the aspects of angular resolution, the maximum count rate and energy resolution over the detector that contains only one crystal.The efficiency is calibrated over a large range of energy by means of theoretical simulation and experiment. MCNP4C, a general Monte Carlo program, is used in the process of theoretical simulation. The results of the theoretical simulation and experiment is compared.The Clover detector is surrounded by 8 crystals of BGO. Each crystal matches two photomultiplier tubes each of which generates an anti-compton signal. The logic OR of the 16 anti-compton signals is used to control the data acquisition system.Kmax, which is a multiple parameters data acquisition system based on CAMAC -BUS , records the data of four output channels of the Clover detector event by event on the computer disk. The efficiency and energy spectrum of the Clover detector is obtained by addition of energy information corresponding to the same event in the process of off lining data processing. The increase of the efficiency resulted from the effect of cross section among the four crystals in one Clover is illuminated in the paper.