R&D Of Two-dimensional Position Sensitive Photoelectric Detector

This paper developed a two-dimensional Position Sensitive photoelectric Detector (2-D PSD), including design, production and testing of this detector. The detector consists of a fluorescence collection system, photoelectric conversion system, the back-end electronics parts and data acquisition system. More specifically, the fluorescence collection system consists of a plastic scintillator and wavelength-shifting fiber; photoelectric conversion system including Multi-Pixel Photon Counter (MPPC) and its ancillary equipment (power supply system); back-end electronics including N1M crate and related plug-ins, etc.; data acquisition system consists of a CAMAC crate and plug-ins, computer and Lab VIEW. The main purpose of the2D-PSD is to detect two-dimensional position of charged particles which also can be used as trigger for the other detectors.As a key component in the2D-PSD, MPPC affects the performance of2D-PSD very much, so a deep research on the MPPC have been done. The results show that the gain and detection efficiency of MPPC will be increased as the bias voltage increases, MPPC has an accurate and effective response to different lighting conditions under appropriate bias condition and good ability to distinguish single-photon in low light conditions as well which also proves that MPPC is the ideal choice as the low light detection component of the PSD.Performance testing should be taken before it’s been used in engineering, here we used radioactive sources in the test. According to the specific circumstances of this experiment, we use the output from a dual coincidence as the trigger for the detector, in order to minimize the error caused by the occasional coincidence made by noise, we need to have a well understanding of the noise, then an appropriate threshold can be chosen. The noise detected by MPPC is mainly concentrated in the single photoelectron events, a few of them come from two-photon events, so we chose2.5p.e as the threshold value. Because of the nonuniform of the efficiency between different light collection channels and read out electronics, we need to do the detection efficiency correction first. Finally, the experiment gives out a position resolution of0.67mm which is very excelent.