Sensors and Materials

Young Researcher Paper Award 2023
🥇Winners

Notice of retraction
Vol. 32, No. 8(2), S&M2292

Print: ISSN 0914-4935
Online: ISSN 2435-0869
Sensors and Materials
is an international peer-reviewed open access journal to provide a forum for researchers working in multidisciplinary fields of sensing technology.

Tweets by Journal_SandM Sensors and Materials
is covered by Science Citation Index Expanded (Clarivate Analytics), Scopus (Elsevier), and other databases.

Instructions to authors
English 日本語

Instructions for manuscript preparation
English 日本語

Template
English

Publisher
MYU K.K.
Sensors and Materials
1-23-3-303 Sendagi,
Bunkyo-ku, Tokyo 113-0022, Japan
Tel: 81-3-3827-8549
Fax: 81-3-3827-8547

MYU Research, a scientific publisher, seeks a native English-speaking proofreader with a scientific background. B.Sc. or higher degree is desirable. In-office position; work hours negotiable. Call 03-3827-8549 for further information.

MYU Research
(proofreading and recording)

MYU K.K.
(translation service)

The Art of Writing Scientific Papers
(How to write scientific papers)
(Japanese Only)

Sensors and Materials, Volume 37, Number 5(2) (2025)
Copyright(C) MYU K.K.

pp. 1977-1991
S&M4035 Research Paper of Special Issue
https://doi.org/10.18494/SAM5597
Published: May 23, 2025

Reduction of γ-ray-induced Noise of Diamond Detector Elements and Estimation of Neutron Detection Efficiency for the Development of a Criticality Proximity Monitoring System for the Decommissioning of the Fukushima Daiichi Nuclear Power Plant [PDF]

Kengo Oda, Junichi H. Kaneko, Yusuke Kobayakawa, Kenichi Watanabe, Youichi Fujita, Eitaro Hamada, Tetsuichi Kishishita, Masaya Miyahara, Masayoshi Shoji, Hironori Uchinoyae, Sho Nishino, Yoshihiko Tanimura, Akiyoshi Chayahara, Takehiro Shimaoka, Hideaki Yamada, Tomohiro Endo, Yuto Akashi, and Manobu M. Tanaka

(Received February 7, 2025; Accepted April 3, 2025)

Keywords: Fukushima Daiichi Nuclear Power Plant Decommissioning Project, criticality proximity monitoring system, diamond detection element, measurement circuit, γ-ray irradiation

In this paper, we discuss the development of a diamond detector element for a criticality proximity monitoring system, which is essential for the decommissioning of the Fukushima Daiichi Nuclear Power Plant. The system must withstand γ-rays at a dose rate of 1 kGy/h with minimal shielding due to payload constraints. We evaluated the effects of γ-rays on prototype diamond detectors and confirmed that removing the lift-off separation surface of diamond membrane by ion beam etching and adding a p+ diamond layer effectively reduced the effect of γ-rays. A prototype detector combined a 180-µm-thick 6LiF sintered neutron-to-charged-particle converter with a diamond detector having a 2.53 mm² sensitive area. With a threshold energy set at 1 MeV, a neutron detection efficiency of 3.0 × 10−4 cps/nv was obtained for a 252Cf source. The combination of a radiation-resistant front-end integrated circuit and a diamond detector resulted in an estimated γ-ray noise level of 0.001 cps at 0.915 MeV, based on the measurements with γ-rays at a dose rate of up to 600 Gy/h using a 60Co source. Furthermore, at a dose rate of 1 kGy/h, the γ-ray noise was 0.0004 cps, satisfying the S/N ratio of ≥1 required by the Feynman-α method. We suggest that by using 1024 diamonds in the future, the criticality proximity monitoring system could achieve a neutron detection efficiency of 1.9 cps/nv.

Corresponding author: Kengo Oda

This work is licensed under a Creative Commons Attribution 4.0 International License.

Cite this article
Kengo Oda, Junichi H. Kaneko, Yusuke Kobayakawa, Kenichi Watanabe, Youichi Fujita, Eitaro Hamada, Tetsuichi Kishishita, Masaya Miyahara, Masayoshi Shoji, Hironori Uchinoyae, Sho Nishino, Yoshihiko Tanimura, Akiyoshi Chayahara, Takehiro Shimaoka, Hideaki Yamada, Tomohiro Endo, Yuto Akashi, and Manobu M. Tanaka , Reduction of γ-ray-induced Noise of Diamond Detector Elements and Estimation of Neutron Detection Efficiency for the Development of a Criticality Proximity Monitoring System for the Decommissioning of the Fukushima Daiichi Nuclear Power Plant, Sens. Mater., Vol. 37, No. 5, 2025, p. 1977-1991.