Testbench of the HICAT RFQ at GSI

In April 2006 the commissioning of the ion linac for the Heidelberg Ion beam Therapy Centrum (HIT) facility in Heidelberg, Germany was started. In preparation of the commissioning of the RFQ cavity beam tests with protons were carried out at GSI. The RFQ for the HIT facility was delivered to GSI in March 2005. A testbench for the RFQ cavity was constructed at GSI to allow for exact measurements of the output energy with the time of flight (ToF) method in addition to previous beam tests at IAP Frankfurt using an analyzing magnet. Due to the fact that a double gap rebuncher is integrated into the RFQstructure, beam studies with different mechanical settings of the rebuncher had to be conducted. For each setting the effective voltage of the rebuncher could be estimated. The final mechanical setting was chosen with respect to required longitudinal matching to the IH structure behind of the RFQ.