ACS cavity for J-PARC linac

Ao, Hiroyuki; Asano, Hiroyuki; Tamura, Jun  ; Ouchi, Nobuo ; Hasegawa, Kazuo; Morishita, Takatoshi  ; Takata, Koji*; Naito, Fujio*; Yamazaki, Yoshishige

An annular-ring coupled structure (ACS) for J-PARC linac has been in mass-production since March 2009. It was planned to fabricate 18 ACS accelerating modules and two debuncher modules for the three years. At present, they are progressing on schedule. The past achievements include: ten accelerating modules were completed on schedule; the frequency tuning of the most accelerating modules was finished except two debencher modules; and 14 accelerating modules have been brazed. One of the mass-produced modules was conditioned up to 1.6 MW, which corresponds to the accelerating field by 15% higher than the designed value of 4.2 MV/m.