Development of low-noise double-sided silicon strip detector for cosmic soft gamma-ray Compton Camera

Double-sided silicon strip detectors (DSSD) provide a very promising technology for constructing a Compton Camera, which is expected to provide a high-sensitivity soft gamma-ray observation in the 0.1-20 MeV energy range. The merits of DSSD are the high-energy resolution, high scattering efficiency, low radio-activation in the orbit, moderate radiation hardness, smaller Doppler broadening, large size, and stable performance. A key feature for optimal performance is the low noise level of the DSSD and the attached frontend electronics. We minimized the noise by optimization of the electrode geometry of the DSSD. We have thus obtained an energy resolution of 1.3 keV (FWHM) for 60 and 122 keV at -10∘C. It was found that the detection efficiency for gamma-rays was uniform over the DSSD and the signal charge split between neighboring strips was not significant. We also confirmed that the Compton imaging by two DSSDs achieved a good angular resolution close to the Doppler-broadening limit.