DOI:
10.1016/j.nima.2014.10.037
IAA authors:
Castro-Tirado A.J.;Jeong S.
Authors:
Chang Y.-Y., Chen C.R., Chen P., Huang J.-J., Huang M.A., Liu T.-C., Nam J.W., Wang M.-Z., Bogomolov V., Brandt S., Budtz-Jørgensen C., Castro-Tirado A.J., Choi H.S., Connell P.H., Eyles C., Jeong S., Kim J.E., Kim M.B., Kim S.-W., Lee J., Lim H., Min K.W., Panasyuk M.I., Park I.H., Petrov V., Reglero V., Řípa J., Rodrigo J.M., Svertilov S., Yashin I.
Journal:
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Abstract:
In this paper we present the Inverted-Conical light guide designed for optical crosstalk reduction in the scintillator-MAPMT assemblies. The research was motivated by the 30% crosstalk observed in UFFO X-ray telescope, UBAT, during the preliminary calibration with MAPMTs of 64 2.88 × 2.88 mm2 pixels and identically gridded YSO crystal matrices. We began the study with the energy and crosstalk calibrations of the detector, then we constructed a GEANT4 simulation with the customized metallic film model as the MAPMT photocathode. The simulation reproduced more than 70% of the crosstalk and explained it as a consequence of the total reflection produced by the photocathode. The result indicated that the crosstalk mechanism could be a common case in most of the contact-assembled scintillation detectors. The concept of the Inverted-Conical light guide was to suppress the total reflection by contracting the incident angle of the scintillation. We optimized the design in the simulation and fabricated a test sample. The test sample reduced 52% crosstalk with a loss of 6% signal yield. The idea of the Inverted-Conical light guide can be adapted by scintillation detectors multi-pixel, imaging-purpose scintillation detectors such as the ultra-fast GRB observatory UFFO-UBAT, whose performances are sensitive to responding time, image resolution, and geometrical modifications. © 2014 Elsevier B.V. All rights reserved.
URL:
https://ui.adsabs.harvard.edu/#abs/2015NIMPA.771...55C/abstract
Keywords:
Crosstalk; GEANT4 simulation; Light guide; MAPMT; YSO