Large-volume Si(Li) orthogonal-strip detectors for Compton effect based instruments

Recent developments of large-area Si(Li) orthogonal-strip detectors have revealed their capability for applications in Compton effect based instruments. Some inherent advantages of silicon like dominance of Compton scattering in photon interactions and operation at room or somewhat lower temperature combined with the availability of large-volume Si(Li) detectors could stimulate the development of powerful Compton instruments. Several 10 and 20 mm thick diodes with a diameter of 102 mm were fabricated. Two 10 mm thick diodes were cut to form a 74 mm /spl times/ 74 mm square with slightly rounded corners. The same position-sensitive structure, 32 strips with a pitch of 2 mm, was produced on the thin Li-diffused n-contact and boron implanted p/sup +/-contact by means of photolithography and plasma etched grooves. The position-sensitive area of 64 mm /spl times/ 64 mm is surrounded by a 5 mm wide guard-ring. One of these 10 mm thick Si(Li) orthogonal-strip detectors will be mounted in a cryostat prepared at LLNL. There, the detector will be extensively tested with the goal to be integrated into the compact Compton camera system consisting of double-sided strip Si(Li) and HPGe detectors.