一米长四翼型RFQ调谐研究(英文)

Tuning of a One-Meter Four-vane RFQ

为获取ADS工程中四翼型RFQ加速器在设计、调谐和运行等方面的经验,设计和建造了一台一米长四翼型RFQ加速器。该RFQ的设计频率为162.5 MHz,但是测量结果显示即使没有调谐器时,腔体的频率也为163.7 MHz。为降低腔体频率,使用四线模型理论进行了分析并重新设计了腔体的端板。使用了二极模稳定杆来加大四极频率与相邻二极频率的间隔。最终测量结果显示,在腔体电压分布没有大的波动的情况下腔体频率达到了设计频率。同时,腔体Q值降低了1%,这就要求需要更多的功率注入腔体。使用水对二极模稳定杆进行了冷却,以便腔体能够稳定工作。

In order to get experiences of design, tuning and running of a four-vane RFQ for the China ADS project, a one-meter four-vane RFQ was designed and fabricated. The quadruple frequency of the RFQ was designed to be 162.5 MHz(operating frequency), but the measured frequency after fabrication was 163.7 MHz even without tuners in the cavity. To reduce the frequency the four-wire line model theory was used, and the endplates were redesigned. Dipole mode stabilizer rods were employed to expand the span of the quadruple frequency and the adjacent dipole frequency. As a result, the quadruple frequency was altered to the operating frequency without rippling voltage distribution along the RFQ severely. Meanwhile, the Q value was reduced by 1%, which means more RF power was required to be fed into the RFQ. The dipole mode stabilizer rods were cooled by water to make the RFQ work stably.