Development of RF input coupler for Inter-digital H-mode drift-tube linac prototype with alternative phase focusing in muon linac

Nakazawa, Yuga*; Iinuma, Hiromi*; Iwashita, Yoshihisa*; Iwata, Yoshiyuki*; Otani, Masashi*; Kawamura, Naritoshi*; Kitamura, Ryo   ; Kondo, Yasuhiro   ; Saito, Naohito; Sue, Yuki*; Hasegawa, Kazuo; Hayashizaki, Noriyosu*; Mibe, Tsutomu*; Morishita, Takatoshi  ; Yasuda, Hiromasa*; Yamazaki, Takayuki*; Yoshida, Mitsuhiro*; Yotsuzuka, Mai*; Cicek, E.*

An inter-digital H-mode drift-tube linac (IH-DTL) is developed in a muon linac at the J-PARC E34 experiment. IH-DTL will accelerate muons from 0.34 MeV to 4.5 MeV at a drive frequency of 324 MHz. Since IH-DTL adopts an APF method, with which the beam is focused in the transverse direction using the rf field only, the proper beam matching of the phase-space distribution is required before the injection into the IH-DTL. Thus, an IH-DTL prototype was fabricated to evaluate the performance of the cavity and beam transmission. As a preparation of the high-power test, tuners and coupler are designed and fabricated. In the low power measurement, we decided the loop structure with witch the VSWR = 1.01 and field distortion of within 7%. In this paper, the development of the tuner and the coupler and the result of the low-power measurement will be presented.