Investigation on a bar detector with 3D position decoding scheme

Simulation studies were performed to find optimum design parameters for a bar detector allowing 3D position decoding of impinging gamma rays. This design incorporates surface treatment, system geometry, photo-sensors, scintillators, and a more robust positioning algorithm. The bar detector simulated consists of a long scintillation crystal, ranged from 5 cm to 20 cm, with a relatively small cross section (4times4 mm²), coupled to two photo sensors, one on each end. Statistical based positioning scheme has been developed to improve positioning accuracy. The method maps event characterization vectors to the associated position based on chi square error. Our simulation shows that a 5cm long bar detector can achieve ~1mm FWHM spatial resolution for a 511 keV gamma photon. The performance improvement of the new positioning scheme over a linear estimator were over 70%. Grounded surface with reflector found to be the most optimum surface condition with respect to the steepest and linear correlation of photo sensor signals. Experimental measurements are in progress to validate the simulation results