Cavities

Linear Accelerators (Linacs) are widely employed in accelerator facilities. Linear acceleration is the method of choice for light particles as synchrotron radiation effects limit the usability of circular accelerators for these particles. Industrial applications require compact linacs for the acceleration of electrons with target energy in the range between 1 and 25 MeV. CST MWS and PS can be used to investigate the high frequency behaviour of linac structures as well as the interaction between particles and the accelerating field. Read full article..

J. Rodnizki, Soreq NRC The SARAF RFQ is a four rod RFQ, operating at a frequency of 176 MHz, designed to bunch and accelerate a 4 mA deuteron/proton beam from 20 keV/nucleon DC up to 1.5 MeV/nucleon CW. The electrodes voltage for accelerating deuterons is 65 kV, a field of 22 MV/m (1.6 Kilpatrick). The RFQ injected power is induced by a loop coupler. The power needed to achieve this voltage is 250 kW, distributed along the 3.80 m RFQ length. This constitutes a power density that is approximately 3 times larger than that achieved in other 4-rod RFQs. The RFQ tank is made of 35 mm thick stainless steel. Its inner surface is electroplated with Copper. At high power, local high surface currents in the RFQ might cause overheating which will lead to out-gassing and in turn to sparking, which will prevent the RFQ from reaching the desired operating power. Therefore, there is a vital need for a detailed RF simulation of the RFQ, in combination with heat transfer simulations, in order to determine a priori the areas that heat up uncontrollably at high power, and aid in the design of further cooling to circumvent these phenomena. These simulations should include the RFQ detailed structure and its water cooling system, which incorporates a total flow of 1000 liter/minute. We used CST MWS to simulate the RF currents and fields in a 3D detailed model of the SARAF RFQ, including its loop coupler. The correct eigenmode was reproduced and both Qe and Qo are consistent with the measured ones. Detailed results reproduced the experimental observation of several overheated regions in the RFQ, including the end flanges and the plungers. Further results predicted overheating at regions around the bottom of several ports in the RFQ tank, as shown in figure 1, which were subsequently measured and are now being fixed by additional cooling. Read full article..

CST MICROWAVE STUDIO® enables the simulation of periodic eigenmode problems such as Travelling Wave Tubes(TWT). The group velocity and phase dispersion characteristics can be extracted as well as the Pierce Impedance. Read full article..

This application has been succesfully simulated using the powerful Eigenmode Solver in CST MICROWAVE STUDIO® with the aid of the Modal Analysis Module. Read full article..