Development of the silicon photo-strip sensor

D.H Kah,H Park,H.O Kim,J.B Bae,H.J Kim,H.J Hyun

doi:10.1109/nssmic.2009.5402228

Abstract

We have designed and fabricated silicon photostrip sensors with polysilicon resistors and coupling capacitors. This developed detector consists of two photo-strip sensors sandwiching opposite faces of a crystal scintillator and being oriented orthogonal to each other. This configuration is able to provides the 2 dimensional position information and to measure the energy. Therefore they can be used in nuclear and medical application. The developed sensor has p + strip array for signal readout. On the other hand, the rear side is a light entrance window which has very thin n + doping layer with anti-reflective coating to prevent light losing. These sensors are fabricated on a 5-in., 380 ¿m-thickness, n-type, high resistivity silicon wafer. The leakage currents of the fabricated sensors are measured as a function of the reverse bias voltages. The light responses of fabricated silicon photosensors coupled with a CsI(Tl) crystal are measured by using 241 Am, 22 Na and 137 Cs radioactive sources. The energy resolutions of the photodiode coupled with the crystal are obtained to be 20.5 % and 13.8 % for the 22 Na (511 keV) and the 137 Cs (662 keV) ¿-rays. The one-dimensional position information by the ¿ particles ( 241 Am) are clearly observed by the photo-strip sensor coupled with the crystal.

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