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To investigate the feasibility of using a form cutter to machine the Radial Matcher Section (RMS) of the Radio Frequency Quadrupole (RFQ) for the Accelerator Driven System (ADS) project at Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS), the influence of RMS end shape on the RFQ cavity frequency is studied. The results indicate that using a form cutter to machine the RMS of an RFQ will indeed influence the cavity frequency. The RMS end shape will give more influence to a shorter RFQ cavity. For the 4.2 m ADS RFQ, the influence is negligible, which means that a form cutter can be used to machine the RMS. 相似文献
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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。 相似文献
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RFQ (射频四极透镜) 是直线加速器中最重要的前级聚焦加速结构,其工作模式下束流孔中的电场四极对称性是保证束流品质及加速效率的关键。为了解决其各自存在的工作模式下四极场的不对称问题,分别对四杆型RFQ 和四翼型RFQ 的结构和模式谐振特性做了研究。针对四翼型RFQ,模拟显示双端口对称耦合的方式从抵消二极模式和提高结构对称性两方面来达到削弱工作模式下的场分布中二极量的目的,对一个1 m段四翼RFQ 模型腔的测量证实了双端口对称耦合抵消腔内二极模式的有效性;针对四杆型RFQ 的二极场,以SSC-Linac 项目的RFQ 为原型,利用三维模拟计算软件CST-MWS 进行模拟,通过改进支撑板的结构并调整参数,完全地消除了工作模式下的极间二极场,且理论上此种改进方法对支撑板结构的四杆型RFQ 均有效。Radio Frequency Quadruple(RFQ) is the most important front-end acceleration structure in linear accelerators.It can focus and accelerate beam in longitudinal and transversal direction, simultaneously. Symmetric of electric field in acceleration aperture is very important for the beam dynamics. To an idea RFQ, there is only quadruple electric field in the acceleration aperture. The dipole field in aperture is harmful and need be as small as possible. The methods to reduce it are studied in a four-rod RFQ and a four-vane RFQ in the article ndependently. To a four-vane RFQ, the symmetrical double-port couplers are employed to counteract the neighboring dipole modes. The availability is confirmed by the simulation with the 3-D Finite Element tool, CST-MWS. And it is also observed by measuring a model-cavity with a symmetrical double-port couplers. To a four-rod RFQ, a new structure of stems is proposed to reduce the dipole mode.Taking the RFQ for the SSC-LINAC project as example, the dipole mode contributions to the electric filed is completely eliminated by selecting stem’s parameters carefully. It is confirmed by the simulation of CST-MWS. heoretically, this method is independent with the frequency of an RFQ and serves for all RFQs with 4-rod or 4-wane structure. 相似文献
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A new special coupler with a kind of bowl-shaped ceramic window for a proton linear accelerator named the Chinese Accelerator Driven System (C-ADS) at the Institute of Modern Physics (IMP) has been simulated and constructed and a continuous wave (CW) beam commissioning through a four-meter long radio frequency quadruple (RFQ) was completed by the end of July 2014. In the experiments of conditioning and beam, some problems were promoted gradually such as sparking and thermal issues. Finally, two new couplers were passed with almost 110 kW CW power and 120 kW pulsed mode, respectively. The 10 mA intensity beam experiments have now been completed, and the couplers during the operation had no thermal or electro-magnetic problems. The detailed design and results are presented in the paper. 相似文献
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C-ADS注入器Ⅱ的RFQ射频系统是该强流加速器的关键一环,它通过两台完全一样的耦合器为一台四边形四翼型RFQ提供和传送功率。该射频系统在设计之初就考虑为10 mA连续束流而进行特殊优化,从功率源、耦合器和功率传输系统几个方面对其进行详细介绍,尤其是针对CW模式下的系统稳定运行以及设备可靠性等方面进行的特殊考虑和模拟方法。该系统已经在2015年通过了10 mA连续束的测试,证实了该射频系统的设计和调试符合物理的实验需求。特别阐述了该系统中一种新的碗型陶瓷窗耦合器的设计思路和一种无环形器情况下的特殊的耦合系数调谐方法,同时推导了双端口耦合的计算方法的具体设置过程。 相似文献
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A 162.5 MHz, 2.1 MeV radio frequency quadruples (RFQ) structure is being designed for the Injector Scheme Ⅱ of the China Accelerator Driven Sub-critical System (C-ADS) linac. The RFQ will operate in continuous wave (CW) mode as required. For the CW normal conducting machine, the heat management will be one of the most important issues, since the temperature fluctuation may cause cavity deformation and lead to the resonant frequency shift. Therefore a detailed multi-physics analysis is necessary to ensure that the cavity can stably work at the required power level. The multi-physics analysis process includes RF electromagnetic analysis, thermal analysis, mechanical analysis, and this process will be iterated for several cycles until a satisfactory solution can be found. As one of the widely accepted measures, the cooling water system is used for frequency fine tunning, so the tunning capability of the cooling water system is also studied under different conditions. The results indicate that with the cooling water system, both the temperature rise and the frequency shift can be controlled at an acceptable level. 相似文献
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A 162.5 MHz, 2.1 MeV radio frequency quadruples (RFQ) structure is being designed for the Injector Scheme Ⅱ of the China Accelerator Driven Sub-critical System (C-ADS) linac. The RFQ will operate in continuous wave (CW) mode as required. For the CW normal conducting machine, the heat management will be one of the most important issues, since the temperature fluctuation may cause cavity deformation and lead to the resonant frequency shift. Therefore a detailed multi-physics analysis is necessary to ensure that the cavity can stably work at the required power level. The multi-physics analysis process includes RF electromagnetic analysis, thermal analysis, mechanical analysis, and this process will be iterated for several cycles until a satisfactory solution can be found. As one of the widely accepted measures, the cooling water system is used for frequency fine tunning, so the tunning capability of the cooling water system is also studied under different conditions. The results indicate that with the cooling water system, both the temperature rise and the frequency shift can be controlled at an acceptable level. 相似文献
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A re-buncher with spiral arms for a heavy ion linear accelerator named as SSC-LINAC at HIRFL (the heavy ion research facility of Lanzhou) has been constructed. The re-buncher, which is used for beam longitudinal modulation and matching between the RFQ and DTL, is designed to be operated in continuous wave (CW) mode at the Medium-Energy Beam-Transport (MEBT) line to maintain the beam intensity and quality. Because of the longitudinal space limitation, the re-buncher has to be very compact and will be built with four gaps. We determined the key parameters of the re-buncher cavity from the simulations using Microwave Studio software, such as the resonant frequency, the quality factor Q and the shunt impedance. The detailed design of a 53.667 MHz spiral cavity and measurement results of its prototype will be presented. 相似文献