A MULTI-LAYER PHOSWICH RADIOXENON DETECTION SYSTEM, REPORTING PERIOD 11/01/06 - 01/31/07

During the third quarter of our research we continued development of our two-channel digital pulse processor, and finalized/optimized our XEPHWICH design. We have completed a number of simulations (using MCNP) on potential design features of a two-channel phoswich detector, and have come to agreement on the most efficient design for the ARSA framework. This design will encompass two planar, triple-layer phoswich detectors positioned parallel to each other such that the gas-counting volume is a very thin disk. This approach creates a counting geometry that is very close to 4{pi}, while simplifying the manufacturing process. For the DPP2, a two-channel fast preamplifier is being designed. The preamplifier will have DC-offset and gain adjustments. As described in the proposal, valid signal pulses from two PMTs are identified and captured in the FPGA and then digitally processed in a dedicated Digital Signal Processor (DSP). The MicroBlaze processor from Xilinx is intended to be replaced with the DSP. The processor is a soft core, meaning that it is implemented using general logic primitives rather than a hard core such as DSP