Fabrication and performance test of a silicon photo-strip detector coupled with a crystal scintillator

We developed a silicon photodetector optically coupled with a crystal scintillator. The silicon photodetector consists of a single crystal and two silicon photo-strip sensors. The silicon photo-strip sensor is designed and manufactured based on a concept of an AC-coupled single-sided silicon strip sensor, but the back-side of the strip sensor is modified to detect scintillation light. One scintillator is sandwiched between two photo-strip sensors. The p+ strip arrays of the photo-strip sensors are oriented orthogonally to each other. This detector configuration provides the two-dimensional position information and the depth of interaction by measuring signal ratios between the first and the second photo-strip sensors. Theses sensors are fabricated on a 5 in., 380μm-thick, n-type and high resistivity silicon wafer. The leakage currents of the fabricated sensors are measured as a function of the reverse bias voltages. We also measured the photo response of the fabricated sensor for the wavelength range from 350 to 1000 nm. The energy resolution of the fabricated photodiode optically coupled with a CsI(Tl) crystal is obtained to be 13.8% for the 137Cs (662 keV) γ-raysγ-rays. The one-dimensional position information by the α-particlesα-particles from 241Am is obtained with the photo-strip sensor optically coupled with the CsI(Tl) crystal. We also measure the two-dimensional position of a LED light source with two photo-strip sensors.