Neutron flux and energy resolution of direct-geometry disk-chopper spectrometer AMATERAS at J-PARC

Article type: Research Article

Authors: Nirei, Masami^{; *} | Kofu, Maiko | Nakajima, Kenji | Kikuchi, Tatsuya | Ohira-Kawamura, Seiko | Murai, Naoki | Harada, Masahide | Inamura, Yasuhiro

Affiliations: Materials and Life Science Division, J-PARC Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan

Correspondence: [*] Corresponding author. E-mail: [email protected].

Abstract: We investigated neutron flux at a sample position and energy resolution of a direct-geometry disk-chopper spectrometer AMATERAS under various chopper conditions and compared them with simulations and calculations. The measured flux was comparable to that of similar high-flux spectrometers. The resolution when using a pulse-shaping chopper correlated well with the analytical calculations, including the thickness of the disk chopper, the sample size, and the penetration depth into the detector. The results show that the chopper, placed at the intermediate distance of the primary spectrometer, functions as a pulse shaper that optimizes the flux and resolution below the incident energy of 10 meV.

Keywords: Disk-chopper spectrometer, AMATERAS, J-PARC

DOI: 10.3233/JNR-230013

Journal: Journal of Neutron Research, vol. Pre-press, no. Pre-press, pp. 1-8, 2024