Development of negative muonium ion source for muon acceleration

Kitamura, Ryo; Bae, S.*; Choi, S.*; Fukao, Yoshinori*; Iinuma, Hiromi*; Ishida, Katsuhiko*; Kawamura, Naritoshi*; Kim, B.*; Kondo, Yasuhiro; Mibe, Tsutomu*; et al.

Physical Review Accelerators and Beams (Internet), 24(3), p.033403_1 - 033403_9, 2021/03

https://doi.org/10.1103/PhysRevAccelBeams.24.033403

A negative muonium ion (Mu) source using an aluminum foil target was developed as a low-energy muon source. An experiment to produce Mu ions was conducted to evaluate the performance of the Mu ion source. The measured event rate of Mu ions was Mu/s when the event rate of the incident muon beam was /s. The formation probability, defined as the ratio of the Mu ions to the incident muons on the Al target, was . This Mu ion source boosted the development of the muon accelerator, and the practicality of this low-energy muon source obtained using a relatively simple apparatus was demonstrated.

Negative muonium ion production with a C12A7 electride film

Otani, Masashi*; Fukao, Yoshinori*; Futatsukawa, Kenta*; Kawamura, Naritoshi*; Matoba, Shiro*; Mibe, Tsutomu*; Miyake, Yasuhiro*; Shimomura, Koichiro*; Yamazaki, Takayuki*; Hasegawa, Kazuo; et al.

Journal of Physics; Conference Series, 1350, p.012067_1 - 012067_6, 2019/12

https://doi.org/10.1088/1742-6596/1350/1/012067

Negative muonium atom (ee, Mu) has unique features stimulating potential interesting for several scientific fields. Since its discovery in late 1980's in vacuum, it has been discussed that the production efficiency would be improved using a low-work function material. C12A7 was a well-known insulator as a constituent of alumina cement, but was recently confirmed to exhibit electric conductivity by electron doping. The C12A7 electride has relatively low-work function (2.9 eV). In this paper, the negative muonium production measurement with several materials including a C12A7 electride film will be presented. Measured production rate of the Mu were 10/s for all the Al, electride, and SUS target. Significant enhancement on electride target was not observed, thus it is presumed that the surface condition should be more carefully treated. There was no material dependence of the Mu averaged energy: it was 0.20.1keV.

Muon profile measurement after acceleration with a radio-frequency quadrupole linac

Otani, Masashi*; Sue, Yuki*; Fukao, Yoshinori*; Futatsukawa, Kenta*; Kawamura, Naritoshi*; Mibe, Tsutomu*; Miyake, Yasuhiro*; Shimomura, Koichiro*; Yamazaki, Takayuki*; Iijima, Toru*; et al.

Journal of Physics; Conference Series, 1067(5), p.052012_1 - 052012_7, 2018/09

https://doi.org/10.1088/1742-6596/1067/5/052012

We have measured the muon beam profile after acceleration using a radio frequency quadrupole linac (RFQ). Positive muons are injected to an aluminum degrader and negative muoniums (Mu) are generated. The generated Mus are extracted by an electrostatic lens and accelerated to 89 keV by the RFQ. The accelerated Mus are transported to a beam profile monitor (BPM) through a quadrupole magnet pair and a bending magnet. The BPM consists of a micro-channel plate, a phospher screen, and a CCD camera. Measured profile in the vertical direction is consistent to the simulation. This profile measurement is one of milestones for realizing a muon linac for measurement of the muon anomalous magnetic moment at the Japan Proton Accelerator Research Complex.

Result of the first muon acceleration with radio frequency quadrupole

Kitamura, Ryo*; Otani, Masashi*; Fukao, Yoshinori*; Futatsukawa, Kenta*; Kawamura, Naritoshi*; Mibe, Tsutomu*; Miyake, Yasuhiro*; Yamazaki, Takayuki*; Kondo, Yasuhiro; Hasegawa, Kazuo; et al.

Proceedings of 9th International Particle Accelerator Conference (IPAC '18) (Internet), p.1190 - 1193, 2018/06

https://doi.org/10.18429/JACoW-IPAC2018-TUPAL076

Muon acceleration using radio-frequency accelerators makes it possible to precisely measure the muon anomalous magnetic moment and the electric dipole moment. The first muon acceleration was demonstrated using a radio-frequency quadrupole (RFQ) linac. A negative muonium ion (Mu) with less than 2 keV energy was produced from an incident muon with 3 MeV energy using a thin aluminum foil target in order to cool the muon beam for the acceleration, because the designed input energy of the RFQ is 5.6 keV. The Mu was first accelerated to 5.6 keV using an electrostatic accelerator, and was subsequently accelerated to 90 keV using the RFQ. This accelerated Mu was selected using a diagnostic beam line and was identified based on Time-Of-Flight measurements.

Current preparation and prospects of the muon acceleration test with RFQ in J-PARC

Kitamura, Ryo*; Otani, Masashi*; Kondo, Yasuhiro; Bae, S.*; Choi, S.*; Fukao, Yoshinori*; Futatsukawa, Kenta*; Hasegawa, Kazuo; Iinuma, Hiromi*; Ishida, Katsuhiko*; et al.

Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.100 - 103, 2017/12

Muon acceleration is an important technique in exploring the new frontier of physics. A new measurement of the muon dipole moments is planned in J-PARC using the muon linear accelerator. The low-energy (LE) muon source using the thin metal foil target and beam diagnostic system were developed for the world's first muon acceleration. Negative muonium ions from the thin metal foil target as the LE muon source was successfully observed. Also the beam profile of the LE positive muon was measured by the LE-dedicated beam profile monitor. The muon acceleration test using a Radio-Frequency Quadrupole linac (RFQ) is being prepared as the first step of the muon accelerator development. In this paper, the latest status of the first muon acceleration test is described.

First trial of the muon acceleration for J-PARC muon g-2/EDM experiment

Kitamura, Ryo*; Otani, Masashi*; Fukao, Yoshinori*; Kawamura, Naritoshi*; Mibe, Tsutomu*; Miyake, Yasuhiro*; Shimomura, Koichiro*; Kondo, Yasuhiro; Hasegawa, Kazuo; Bae, S.*; et al.

Proceedings of 8th International Particle Accelerator Conference (IPAC '17) (Internet), p.2311 - 2313, 2017/06

https://doi.org/10.18429/JACoW-IPAC2017-TUPVA097

Muon acceleration is an important technique in exploring the new frontier of physics. A new measurement of the muon dipole moments is planned in J-PARC using the muon linear accelerator. The low-energy (LE) muon source using the thin metal foil target and beam diagnostic system were developed for the world's first muon acceleration. Negative muonium ions from the thin metal foil target as the LE muon source was successfully observed. Also the beam profile of the LE positive muon was measured by the LE-dedicated beam profile monitor. The muon acceleration test using a Radio-Frequency Quadrupole linac (RFQ) is being prepared as the first step of the muon accelerator development. In this paper, the latest status of the first muon acceleration test is described.

New muonium HFS measurements at J-PARC/MUSE

Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12

https://doi.org/10.1007/s10751-016-1331-4

Direct measurement of nanoscale lithium diffusion in solid battery materials using radioactive tracer of Li

Ishiyama, Hironobu*; Jeong, S.-C.*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Jung, H. S.*; Miyatake, Hiroari*; Oyaizu, Mitsuhiro*; Osa, Akihiko; Otokawa, Yoshinori; et al.

Nuclear Instruments and Methods in Physics Research B, 376, p.379 - 381, 2016/06

https://doi.org/10.1016/j.nimb.2015.12.036

Evaluation of tritium release properties of advanced tritium breeders

Hoshino, Tsuyoshi; Ochiai, Kentaro; Edao, Yuki; Kawamura, Yoshinori

Fusion Science and Technology, 67(2), p.386 - 389, 2015/03

https://doi.org/10.13182/FST14-T35

Demonstration power reactors (DEMOs) require advanced tritium breeders that have high stability at high temperatures. Therefore, the pebble fabrication of LiTiO with excess Li (LiTiO) as an advanced tritium breeder was carried out. In this study, a preliminary examination of the tritium release properties of advanced tritium breeders was performed. DT neutron irradiation experiments were performed at the fusion neutronics source (FNS) facility in JAEA. The LiTiO pebbles exhibited good tritium release properties similar to the LiTiO pebbles. In particular, the released amount of HT gas for easier tritium handling was higher than that of HTO water.

Measurement of tritium penetration through concrete material covered by various paints coating

Edao, Yuki; Kawamura, Yoshinori; Kurata, Rie; Fukada, Satoshi*; Takeishi, Toshiharu*; Hayashi, Takumi; Yamanishi, Toshihiko

Fusion Science and Technology, 67(2), p.320 - 323, 2015/03

https://doi.org/10.13182/FST14-T20

The present study aims at obtaining fundamental knowledge for tritium transfer behavior and interaction between tritium and paint coated on concrete walls. The amounts of tritium penetration and release in cement paste with epoxy and urethane paint coatings were measured. The tritium penetration amounts were increased with the HTO exposure time. Time to achieve each saturate tritium value was more than 60 days for cement paste coated with epoxy paint and with urethane paint, while cement paste without paint took 2 days to achieve it. Tritium penetration rates were estimated by an analysis of diffusion model. Although their paint coatings were effective for reduction of tritium penetration through the cement paste exposed to HTO for a short period, the amount of tritium trapped in the paints became large for a long time. This work has been performed under the collaboration research between JAEA and Kyushu University.