7th Asia-Pacific Conference on Plasma Physics, 12-17 Nov, 2023 at Port Messe Nagoya

Neutron resonance spectroscopy using a single pulse oflaser-driven neutrons
Zechen Lan1, Tianyun Wei1, Takehito Hayakawa2, Takashi Kamiyama3, Hirotaka Sato3,
Yasunobu Arikawa1, S. Reza Mirfayzi4, Mitsuo Koizumi5, Yuki Abe1, Alessio Morace1,
Takato Mori1, Yuta Tatsumi1, Hiroaki Nishimura, Kunioki Mima1, Mitsuo Nakai6,Shinsuke Fujioka1, Ryosuke Kodama1 and Akifumi Yogo1
1
Institute of Laser Engineering (ILE), Osaka University, Japan2National Institute for Quantum Science and Technology, Japan
3
Faculty of Engineering, Hokkaido University, Japan
4
Tokamak Energy Ltd, UK.
5Japan Atomic Energy Agency, Japan
6Fukui University of Technology, Japane-mail (speaker): lan-zc@ile.osaka-u.ac.jp
In recent decades, neutron resonance diagnosis
technology has been developed and significantly
concerned for non-destructive detection and isotope
identification. Meanwhile, a new approach of neutron
generation, a Laser-Driven Neutron Source (LDNS) has
been attracting a broad interest because of its ultra-shortpulse duration and high flux. Here, we apply the LDNS
to the Neutron Resonance Spectroscopy (NRS) [1] andexplore a new direction of Nuclear Photonics research.
The LDNS was developed using LFEX laser at
Institute of Laser Engineering, Osaka University. As
shown in Fig.1, the LDNS consists of a foil target and asecondary target which work as ion source and neutron
source respectively. The secondary target (neutrongenerator) is set downstream from the foil target(laser-accelerated ion source), the high energy ionsgenerate neutrons with a yield of up to ~1011 within 1 ns
via nuclear reactions such as 9Be(p,n)9B and 9Be(d,n)10B[1]. The fast neutrons generated by LDNS are
decelerated by a neutron moderator to meet experimental
needs. For example, typical resonance energy levels exist
in the region of several eV. In this study, we designed acompact neutron moderator with HDPE (high densitypolyethylene). The size of moderator was optimized by aMonte Carlo simulation, taking a best balance between
high neutron flux and short pulse duration in eV energy.
A clear neutron resonance spectroscopy was obtained insingle shot of LDNS [1], as shown in Fig 2. This method
greatly reduces the limitations of conventional NRS

Fig.1: The experimental setup.

measurements, when the spectrum is obtained by time
integration over a few hours[2].

Fig.2: Neutron transmission of resonance[1].
Using the technique of the single-shot NRS, we try torealize a “nuclear thermometer”[2] by the LDNS. The
experimental setup is shown in Fig.1. A 6Li-glass
scintillator was coupled with a Gated-PMT to work as anepithermal neutron TOF (time-of-flight) detector which
was set at 1.8m far from main target. A neutron
collimator made by 10% Boron dopped polyethylene
was set alone neutron beam line. Two resonance samples,
plates of silver (Ag) and tungsten (Ta), were put on thebeamline toward the epithermal neutron detector. The Ag
plate was kept at room temperature, as a reference
sample, and the Ta plate was heated to high temperature.
The resonance peaks of 109Ag at 5.19eV and 181Ta at
4.28eV were clearly identified, when the resonance peakof 181Ta showed the Doppler broadening depending on
the temperature, suggesting that temperature of nuclei inthe sample can be analyzed by the evaluation of theDoppler broadening. Meanwhile, the pulse duration ofmoderated LDNS was evaluated by analyzing resonancewidth. With the compact source, neutrons around energyof 5 eV have pulse duration less than 1μs.
This work was funded by Grant-in-Aid for Scientific
Research (No. 25420911, No. 26246043, and No.
22H02007) of MEXT, A-STEP (AS2721002c), andPRESTO (JPMJPR15PD) commissioned by JST.
References[1] A. Yogo, Z. Lan, Y. Arikawa, et al. Physical ReviewX, 2023, 13(1): 011011.
[2] K. Tokuda, T. Kamiyama, et al. Jpn. J. Appl. Phys.
40(2001) pp. 1504-1507