Plasma and Fusion Research

Volume 16, 1302106 (2021)

Letters

Investigation of Light Transmission Efficiency in ITER Hard X-Ray Monitor
Shin KAJITA, Santosh P. PANDYA1), Richard O'CONNOR2), Robin BARNSLEY2) and Huxford ROGER3)
Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8603, Japan
1)
Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar - 382428, India
2)
ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex, France
3)
RBH Optics, Burgess Hill, England, United Kingdom
(Received 16 September 2021 / Accepted 31 October 2021 / Published 10 December 2021)

Abstract

A Hard X-ray monitor (HXRM) diagnostic system is being designed for ITER tokamak and will be utilized to detect runaway electrons for the safe operation of the tokamak. Runaway electrons produce X-ray photons by means of thick target and/or thin target bremsstrahlung emission process. In this diagnostic measurement system, the X-ray photons interact with scintillator detector volume and generate secondary UV-photons by luminescence. These UV-photons from the scintillator-crystal guided through the optics and detected by photomultiplier tubes. The light collection efficiency from the scintillator-crystals and light transmission efficiency of the optics determines the detectable energy range of X-rays and energy resolution. In this letter, we perform ray-tracing simulations of the luminescence to optical fiber bundle to assess light collection efficiency from the scintillator-crystal and show the effect on the total light coupling efficiency of the system.

Keywords

ITER, hard X-ray monitor, scintillator, ray tracing, runaway electron

DOI: 10.1585/pfr.16.1302106

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