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 of 0.2- 20 MeV. The detector,
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 has been characterized with repeated
measurements of its spectral and Compton imaging response to
gamma -rays from radioactive sources such as Na,
Cs, Y and Am-Be.
The detector shows a linear response to gamma -rays in the
energy range 511 keV -4.4 MeV,
with an energy resolution (FWHM) of Delta E/E=8.8% : sqrt(1MeV /E).
Compton imaging of Y gamma -ray events with two detected
interactions is consistent with an angular resolution of ~ 3 degrees
(RMS) at 1.8 MeV.