ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES, vol.120, no.4, 1996 (SCI-Expanded)
The Tracking and Imaging Gamma-Ray Experiment (TIGRE) was designed to observe cosmic gamma ray sources at energies of 0.3 to 100 MeV. It uses multi- layer silicon strip detectors to track Compton recoil electrons and positron- electron pairs and small CsI(Tl) crystals to measure the position and energy of the scattered photon. The energy and momentum of the scattered electron and the scattered photon allows the determination of the incident direction uniquely. Traditional Compton telescopes all use a time-of-flight between two detectors, whereas TIGRE uses the electron track in the silicon strips to distinguish between upward and downward moving photons. This allows one to decrease the distance between the two detection arrays thereby increasing the instrument efficiency significantly. TIGRE is also a gamma-ray polarimeter, making use of the sensitivity of the Klein-Nishina cross section for large Compton scatter events. We discuss the results of the up/down tracking discrimination, CLAD imaging and the polarimetry properties of TIGRE.