HIGH-PRESSURE XENON ELECTRONICALLY COLLIMATED CAMERA FOR LOW-ENERGY GAMMA-RAY IMAGING

A high pressure xenon scintillation drift chamber with 30 cm diameter field of view has been built and tested as a two-dimensional imaging c amera for low energy gamma-rays. Experiments demonstrate that the came ra can be also operated in an electronically collimated mode as a thre e-dimensional imaging Compton camera. A spatial resolution of 25 mm is measured for a 140 keV point-like source placed 10.5 cm in front of t he camera without any collimator. The resolution is limited by the int rinsic resolution of the 19 channel readout system which is based on 8 0 mm diameter phototubes. A way to improve the imaging performance is discussed.