【摘要】 基于蒙特卡罗的模拟方法,设计了一个基于塑料闪烁光纤阵列的γ射线位置灵敏探测器并对其性能进行了系统的研究。分析了该探测器在高能γ粒子辐照下的康普顿散射特性和圆形塑料闪烁光纤的能量泄漏情况,发现随着入射能量的不同,康普顿边缘峰值也相应变化,并且和入射光子能量一一对应。考虑阵列间粒子串扰的情况下,利用此特性得到该位置灵敏探测器在0.8~7.0 MeV的γ入射能量下,能量分辨率和空间分辨率分别能够达到10%和cm量级。但由于闪烁光纤原子序数较低,在较高能区的探测效率也较低,只有15%左右或更低。这就使得利用闪烁光纤阵列探测器不能同时满足较好的空间分辨率和能量分辨率,两者出现一定的矛盾。更多还原

【Abstract】 In the last decade a great effort has been made to develop the position-sensitive device forγ-ray imaging and pixel detectors,scintillation or semiconductor,have been widely used.Currently the the MeVγ-ray spectroscopy has been desired in many fields.Unfortunately,there is no existingγ-ray spectroscopy that performs perfectly in such energy range and some detector systems have been proposed for the purpose.As commonly used for pixel detectors,scintillating fibers have the advantage of that they may achieve both the spatial and energy resolution in detectingγ-rays.We simulate the electron spectrum produced in the fiber via Compton scattering mechanism only and energy deposition spectrum including the photoelectron and electron-positron pair creation mechanisms to the interactions withγ-ray photons.We can see that the spectrum might allow determining the energy of the incomingγ-rays,if the Compton edge of the spectrum can be determined.The results of the simulation also show that the energy resolution can be achieved about 10%,and the cross-talks affect little on energy resolution in the bundle configuration.For detectingγ-rays with energies in the range of several MeV,a fiber of radius of about a few centimeters needs to be used to achieve this resolution.These results suggest that the detector configuration might be used in achieving certain degree energy resolution in detectingγ-rays under certain circumstances.Since we choose the low mass material to achieve high probability of Compton scattering,another problem is that the detection efficiency for PSF in this energy range is quite low.It is about 15% or less.There exists a contradiction to obtain both well.更多还原