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A proof-of-concept experiment was performed to demonstrate the three-dimensional imaging capabilities of an all-germanium Compton camera for near-field sources. Eight high purity germanium (HPGe) coaxial detectors were configured in two planes of four detectors each. The data acquisition system was assembled from available hardware and off-the-shelf electronics using standard NIM and CAMAC modules. Sixteen-parameter data were recorded event-by-event for later analysis and image reconstruction. The energy resolution of the system was 0.3% at 1333 keV. Preliminary analysis indicates the position resolution for a source at one meter and a specific detector geometry was less than a centimeter.

The reaction 7o~e~160, 2p2n) Sr with E~160) 80 MeV was used to study the nucleus Sr. Measurements were made of the excitation functions, angular distributions, and y-y-t coincidences.From these measurements six new levels were placed in the level scheme of ' Sr at 2683.7, 3609.2, 4367.1, 5308.4, 6364.4, and 7827.8 keV. A gamma ray with a very high anisotropy [ A2 ---1.05 (7), Aq --0.12(6)] feeds the (11 ) level at 5914.5 keV; A new band based on the level at 3525.7 keV was identified. The sequence of transitions decaying down the negative parity band was reordered to S22-1005-876-694 keV.

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Event-restricted Monte Carlo simulations are used to simulate Compton telescope data sets. The data sets can be used for evaluation of different reconstruction techniques and to assess the relative performance of different telescope geometries. These simulations restrict computations to photons which interact in the detectors under specific conditions (i.e., produce "valid events"), thus significantly reducing computational time and effort. This paper describes the computer code, the restrictions that are imposed on the Monte Carlo modeling and presents some examples of reconstructed data sets that were produced.

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