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.

中文翻译：

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CADS质子直线加速器RFQ光束匹配研究

对于大功率射频四极 (RFQ) 加速器，通常需要设计较大的接受度，以减少 RFQ 腔内的光束损耗。这可能允许不匹配的光束传输到下游腔，从而导致沿下游直线加速器的光束损失。找到beam和RFQ的匹配条件具有重要意义。RFQ的匹配点可以通过测量RFQ上下游的发射度来确定，耗时较长，因此应该采用传输效率扫描的方法来寻找。本文比较了CADS上的发射率、传输效率和匹配点之间的关系1,2询价。结果表明，高传输效率的加权平均点可以作为RFQ的匹配点。该结论可广泛用于波束调试，并且已在其他 RFQ 上开发了传输效率扫描匹配 (TESM) 代码。