Research Of Beam Matching On Rfq For Cads Proton Linac

For a high-power Radio Frequency quadrupole (RFQ) accelerator, it is often necessary to design a large acceptance to decrease the beam loss inside the RFQ cavity. This could allow a mismatched beam to transmit to downstream cavities, which causes beam loss along the downstream linac. Finding the matching condition of beam and RFQ is of great significance. The matching point of RFQ can be confirmed by measuring the emittance at the upstream and downstream of RFQ, which takes a long time, so the transmission efficiency scanning method is supposed to find. This paper compares the relationship among emittance, transmission efficiency, and matching point on CADS1,2 RFQ. The results show that the weighted average point of high transmission efficiency could be regarded as the matching point of RFQ. This conclusion can be widely used in beam commissioning, and the Transmission Efficiency Scanning-matching (TESM) code has been developed on other RFQs.