DESIGN STUDY OF NOVEL LIGHT GUIDE GEOMETRY FOR SCINTILLATION COUNTERS

Abstract

Two scintillating panels (S1 and S2) have been used as triggers in the high resolution spectrometers in HallAofthe Thomas Jefferson NationalAccelerator Facility. New panels are to be installed in place of S1 and S2 and it was proposed that the currently used 90° twisted light guides be replaced by a new adiabatic S-shape design (2 or 3 strips). Using CERN's Guide7, Monte Carlo simulations were performed on four different light guide geometries: rectangular, standard fishtail, 2-strip S-shape and 3-strip S-shape. It was found that the two S-shape designs gave roughly 2x improvement on collection efficiency and 1.2-1 .4x improvement on time resolution oversimple designs (rectangular and fishtail). The 3-strip S-shape guide (90 pico-second time resolution and a 30% collection efficiency) was recommended for replacement of the twisted shape; actual experimental comparisons are also advised.