Simulation of position-sensitive γ-ray detector based on plastic scintillating fiber array

In the last decade a great effort has been made to develop the position-sensitive device for γ-ray imaging and pixel detectors, scintillation or semiconductor, have been widely used. Currently the the MeV γ-ray spectroscopy has been desired in many fields. Unfortunately, there is no existing γ-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 detecting γ-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 with γ-ray photons. We can see that the spectrum might allow determining the energy of the incoming γ-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 detecting γ-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 detecting γ-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. ©, 2015, Editorial Office of High Power Laser and Particle Beams. All right reserved.