Compton scattering sequence reconstruction algorithm for the liquid   xenon gamma-ray imaging telescope (LXeGRIT)
  The Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT) is a balloon born experiment sensitive to \g -rays in the energy band of 0.2-20 MeV. The main detector is a time projection chamber filled with high purity liquid xenon (LXeTPC), in which the three-dimensional location and energy deposit of individual \g -ray interactions are accurately measured in one homogeneous volume. To determine the \g -ray initial direction (Compton imaging), as well as to reject background, the correct sequence of interactions has to be determined. Here we report the development and optimization of an algorithm to reconstruct the Compton scattering sequence and show its performance on Monte Carlo events and LXeGRIT data. 
U.G. Oberlack, E. Aprile, A. Curioni, V. Egorov, K.L. Giboni (Columbia   University)