Power-balance control by Slug Tuner for the 175MHz Radio-Frequency quadrupole (RFQ) linac in IFMIF project

Maebara, Sunao; Moriyama, Shinichi; Saigusa, Mikio*; Sugimoto, Masayoshi; Imai, Tsuyoshi*; Takeuchi, Hiroshi

Fusion Science and Technology, 47(4), p.941 - 945, 2005/05

https://doi.org/10.13182/FST05-A810

For tuning the 175MHz RFQ used in the baseline design of IFMIF, the RF power-balance control by slug tuner is indispensable because the RF power-balance for quadrupole operation mode (TE) in each RFQ quadrant will be affected by the insertion of the loop antennas and pick-up coils. In this study, RF power-balance recovery by slug tuners have been measured by using a low power module of 175MHz RFQ mock-up. The optimal insertion depth of loop antenna was determined to be 3 cm for realizing the appropriate phase differences of TE mode. Under this condition, cylindrical slug tuners were inserted, and S parameters in each cavity were measured. As a typical result, RF power-balance control less than 20% error can be achieved in case of 3cm tuner up to 3cm insertion.