Session 43. Missions and Instruments
Display, Friday, November 10, 2000, 8:00am-6:00pm, Bora Bora Ballroom

## [43.12] Spectroscopy and Imaging Performance of the Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT)

E. Aprile (Columbia University), LXeGRIT Collaboration

LXeGRIT is a balloon-borne Compton telescope based on a liquid xenon time projection chamber (LXeTPC) for imaging cosmic \gamma-rays in the energy band 0.2- 20 MeV. The detector, with 400~cm2 area and 7 cm drift gap, is filled with high purity LXe. Both ionization and scintillation light signals are detected to measure the energy deposits and the three spatial coordinates of individual \gamma-ray interactions within the sensitive volume. The TPC spectral and Compton imaging response has been characterized with a series of laboratory experiments, using \gamma-rays and neutrons from radioactive sources such as 22Na,137Cs, 88Y and Am-Be. The detector shows a linear response in the energy range 511~keV -- 4.4~MeV, with an energy resolution (FWHM) of \Delta E/E=8.8% \: \sqrt{1~MeV /E}. Compton kinematics has been applied to reconstruct the correct sequence of multiple Compton interaction events. Imaging of 88Y events with two and three interactions is consistent with an angular resolution of ~ 3 degrees (RMS) at 1.8~MeV.