Status of POP demonstration of 400 MeV H laser stripping at J-PARC RCS

J-PARC 3GeVにおける400MeV負水素イオンのレーザー荷電変換原理検証実験の状況

Saha, P. K.   ; 原田 寛之  ; 金正 倫計  ; 米田 仁紀*; 道根 百合奈*; 佐藤 篤*; 柴田 崇統*

Saha, P. K.; Harada, Hiroyuki; Kinsho, Michikazu; Yoneda, Hitoki*; Michine, Yurina*; Sato, Atsushi*; Shibata, Takanori*

To eliminate the issues and practical limitations associated with a stripper foil used in a proton accelerator for the charge-exchange injection of H beam, we are preparing for a POP (proof-of-principle) demonstration of foil-less H charge-exchange injection by using only lasers at J-PARC. A prototype YAG laser system has been developed and keep continuing its upgrade through experimental studies of 3 MeV H neutralization. To sufficiently reduce the seed laser energy, we have also developed a multi-reflection laser cavity system, which has as many as 32 reflections overlapped at the interaction point of the ion beam. In 2022, we have obtained nearly 20% flat neutralization for over 40 s of the ion beam. In addition, the spot neutralization (estimated from the fraction overlap with the ion beam due to a tiny laser spot) was obtained to be nearly 100%. This implies the significant merit of the cavity to reduce the seed laser power. The POP demonstration of 400 MeV H stripping will be started in 2023.