Development of a multi-channel signal optimizer for a Compton camera system

A multi-channel differential-to-single-ended signal optimizer has been developed for application in a low-energy Compton camera system. The developed multi-channel signal optimizer enhanced the signal-to-noise ratio of the whole system compared to the case in which a simple resistive network converter was used. In order to verify the performance of the developed signal optimizer, we performed an energy measurement for gamma rays emitted from Am-241, Ba-133 and Cs-137 standard sources by using a double-sided silicon strip detector. The energy resolution of 19 keV, full width at half maximum, was obtained by fitting a 59.6-keV gamma-ray peak, and the energy threshold level of time pick-up circuits was determined to be 35 keV by comparing the measured energy spectrum with a simulated one obtained with a Monte Carlo code. The obtained energy resolution and the energy threshold level show that the developed signal optimizer can effectively enhance the signal-to-noise ratio for multi-channel electronics and enables us to construct a Compton camera system combined with low-cost commercially-available multi-channel electronics.