A 175MHz RFQ Design for IFMIF Project

An RF power-balance effects by a multi-drive loop antenna and a slug tuner have been investigated for a 175MHz RFQ design. For the multi-loop antenna, a good power balance with four-loop antenna was measured by a low power test using a 175MHz RFQ mock-up module, in comparison with those with a single loop and two-loop antennas. For the four-loop antenna, it was also found that the electric field distortion in beam bore is less than 1% from calculation results. As for the slug tuner, it was found that RF power-balance up to 80% can be controlled without overlap of modes from the low power test. The calculation results suggested that the RFQ design requirement of a distortion factor limit of 1% can be attained by employing a 1cm slug tuner with the insertion depth of 1cm or less.