Energy Spectrums from Unshaped Signals

Digital signal processing was used to produce an energy spectrum from the raw output of a preamplifier. It is our hope to use the signals generated from the preamplifier for pulse shape discrimination. Therefore we needed to generate a energy spectrum without relaying on the shaping done by an amplifier. The voltage pulse produced by a germanium detector was recorded with a flash ADC. The data was then filtered twice, first using a low-pass recursive filter to get rid of high frequency noise and again to remove lower frequency problems. The resulting pulse was integrated to determine the energy. This was tested with various spectrums and produces expected results with a small decrease in energy resolution as compared to shaped data. At this time optimal filtering is being studied as a possible way to increase energy resolution.