Evaluation of 0.5-mm thick double-sided silicon strip detector for Compton telescope

Double-sided silicon strip detector (DSSD) is a key component to construct the next generation Compton telescope for the high-sensitivity observation in the energy region from several hundred keV to MeV. The concept of Compton camera we consider is using DSSD for scatterer, and high-stopping CdTe pixel detector for absorber. As the scatterer, DSSD has advantages of smaller band gap, higher efficiency of scattering, smaller Doppler broadening, good response time, and smaller number of readout channels. We have developed and confirmed that 0.3 mm-thick DSSD has enough performance. As a next step, in order to obtain more efficiency of higher energy gamma-rays, we developed newly designed DSSD which increase in thickness to 0.5 mm. We measured the basic properties of 0.5 mm thick DSSD, in terms of leakage current, capacitances, and noise characteristics. They can be full-depleted around 200 V, and we obtained the energy resolution of 1.3 keV (FWHM) for 60 keV at -10 °C from one p-side strip. We also set up the newly developed read-out system which is based on technology of operating ASICs on floating ground, and performed 64 ch read-out on one side.