KEK, Ibaraki, Japan
JAEA/J-PARC, Tokai-mura, Japan
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
Ibaraki University, Ibaraki, Japan
Nagoya University, Nagoya, Japan
RIKEN Nishina Center, Wako, Japan
University of Tokyo, Tokyo, Japan
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Negative muonium ion production is one of methods to cool muons. Since its discovery in 1987 by interactions of muons with a metal foil, it has been discussed that the production efficiency would be improved using a low-work function material. C12A7 (12CaO·7AlO3) 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 lower work function (2.9 eV) and it was reported that nearly the same negative current signal as that with a bi-alkali material coated metal were observed in H− formation. In this poster, the negative muonium production measurement with a Al foil and C12A7 electride film will be presented.
Nagoya University, Nagoya, Japan
KEK, Ibaraki, Japan
JAEA/J-PARC, Tokai-mura, Japan
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
KMI, Nagoya, AIchi Prefecture, Japan
Ibaraki University, Ibaraki, Japan
JAEA, Ibaraki-ken, Japan
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
University of Tokyo, Tokyo, Japan
The J-PARC E34 experiment aims to measure the muon anomalous magnetic moment and the electric dipole moment with a high precision. In this experiment, ultra-slow muons generated from thermal muonium production and laser resonance ionization are accelerated in a multistage muon linac. In order to satisfy the experimental requirements, a suppression of the emittance growth between different accelerating cavities is necessary, and the transverse and longitudinal beam matching is important. Longitudinal beam monitor has to measure the bunch width with a precision of 1% corresponding to several tens of picoseconds. In addition, the beam monitor should be sensitive to a single muon, because the beam intensity during the commissioning is lower than the designed intensity. Therefore, we are developing a longitudinal beam monitor using a microchannel plate (MCP), and a measurement system using photoelectrons to estimate the performance of the beam monitor. On November 2018, the beam monitor has been successfully used in the muon RF acceleration test at the J-PARC. In this presentation, the results of the performance evaluation for this beam monitor are reported.