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.
|Number of pages||11|
|Journal||Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment|
|Publication status||Published - 2015 Jan 21|
Bibliographical noteFunding Information:
This work was supported by Taiwan׳s Ministry of Science and Technology (MOST) Vanguard Program ( 102-2628-M-002-010 ), Taiwan׳s National Space Organization (NSPO) supported by MOST , the Creative Research Initiatives program (RCMST) of MSIP/NRF in Korea , the Spanish MINECO through project number AYA 2009-14000-C03-01/ESP , AYA 2012-39727-C03-01/ESP and AYA 2011-29936-C05-01 , the program of development of Lomonosov Moscow State University , and NRF SRC program 2010-0027910 of Center for Galaxy Evolution Research.
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All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics