Detection of 14-MeV neutrons by optical system with radioluminescence material and optical fiber

T. Shikama, K. Toh, S. Nagata, B. Tsuchiya, M. Yamauchi, T. Nishitani

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Detection of the 14-MeV neutrons in the D-T fusion reaction is an important topic in burning plasma diagnostics. Simple, compact, robust, and easy to maintain are strongly preferable features for the 14-MeV neutron detection system. An optical dosimetry system, composed of a radiation-resistant thin optical fiber, with a small radioluminescence material attached to one end, satisfies these requirements. Irradiation tests for two types of strontium-aluminates (SrAl2O4:Eu2+,Dy3+ and Sr4Al14O25:Eu2+,Dy3+) were performed using a 14-MeV fusion neutron, 0.5-2 MeV protons, and 60Co γ-ray. Both types of strontium-aluminates emit strong radioluminescence under the 14-MeV neutron irradiation. SrAl2O4:Eu2+,Dy3+ emit strong radioluminescence under the 14-MeV neutron irradiation. However, SrAl2O4:Eu2+,Dy3+ continue to emit luminescence after the irradiation stops. The radioluminescent spectrum of Sr4Al14O25:Eu2+,Dy3+ have characteristic peaks at approximately 400, 480, and 570 nm though the peaks can not distinguish in case of SrAl2O4:Eu2+,Dy3+. The peak at 570 nm promptly disappeared when the neutron radiation stopped though the peaks at 400 and 480 nm indicate long lasting phosphorescence. Therefore, a rapid change of the 14-MeV neutron flux could be monitored by the radioluminescence peak intensity at 570 nm. The spectrum for the 14-MeV neutrons is different from those for the ions and γ-ray irradiation. Thus, the 14-MeV neutron flux can be distinguished from ion influxes as well as from background γ-ray by measuring a detailed spectrum of the radioluminescence. The present system, being compact, simple and robust, can detect the D-T 14-MeV neutrons, discriminating 14-MeV neutrons from the background ions and γ-ray. There is a possibility to discriminate neutron energy with the present optical system.

Original languageEnglish
Title of host publicationOptical Fiber Sensors, OFS 2006
PublisherOptical Society of America
ISBN (Print)1557528179, 9781557528179
Publication statusPublished - 2006 Jan 1
EventOptical Fiber Sensors, OFS 2006 - Cancun, Mexico
Duration: 2006 Oct 232006 Oct 23

Publication series

NameOptics InfoBase Conference Papers
ISSN (Electronic)2162-2701

Other

OtherOptical Fiber Sensors, OFS 2006
Country/TerritoryMexico
CityCancun
Period06/10/2306/10/23

ASJC Scopus subject areas

  • Instrumentation
  • Atomic and Molecular Physics, and Optics

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