Coupling factor evaluation of the RF input coupler for the IFMIF/EVEDA RFQ linac

IFMIF/EVEDA RFQライナックにおけるRF入力結合系の結合度評価

前原 直; 市川 雅浩; Palmieri, A.*

Maebara, Sunao; Ichikawa, Masahiro; Palmieri, A.*

In the design of prototype RFQ linac for the IFMIF/EVEDA Project, a 175 MHz RFQ, which has a longitudinal length of 9.78 m, was proposed to accelerate deuteron beam up to 5 MeV. The operation frequency of 175 MHz was selected to accelerate a large current of 125 mA in CW mode. The overall driving RF power of 1.28 MW by 8 RF input couplers has to be injected to the RFQ cavity. As a part of the validation of the coupler design, the beta factor (coupling coefficient) was measured on Aluminum RFQ at INFN Legnaro with on-purpose, real-scale dummy aluminum couplers for the installed depths of L = 27, 40, 45, 48 and 73 mm. In this article, measurement and calculation results performed with the 3D code HFSS for coupling factor evaluation will be presented in details.