Energy Dispersion Compensation and Beam Loading in X-band Linacs for the Jlc/nlc§
نویسندگان
چکیده
The shape of an RF pulse is distorted upon propagating through an X-band accelerator structure due to dispersive effects. This distortion together with beam loading introduce energy spread between 192 bunches. In order to minimize this energy spread we modify the input RF pulse shape. The pulse propagation, energy gain, and beam loading are modelled with a mode-matching computer code and a circuit model. A 2D model and a circuit model of a complete 60 cm structure, consisting of 55 cells and input and output couplers is analyzed. This structure operates with a 5π/6 phase advance per cell. Dispersive effects for this structure are more significant than for previously studied 2π/3 phase advance accelerating structures. Experimental results are compared with the theoretical model and excellent agreement is obtained for the propagation of an RF pulse through the structure. Paper presented at the 2003Particle Accelerator Conference Portland, Oregon, USA May 12-May 16, 2003 Work supported in part by Department of Energy Contract DE-AC03-76SF00515 ENERGY DISPERSION COMPENSATION AND BEAM LOADING IN X-BAND LINACS FOR THE JLC/NLC 1 R.M. Jones, V.A. Dolgashev, R.H. Miller, C. Adolphsen and J.W. Wang; SLAC, USA Abstract The shape of an RF pulse is distorted upon propagating through an X-band accelerator structure due to dispersive effects. This distortion together with beam loading introduce energy spread between 192 bunches. In order to minimize this energy spread we modify the input RF pulse shape. The pulse propagation, energy gain, and beam loading are modelled with a mode-matching computer code and a circuit model. A 2D model and a circuit model of a complete 60 cm structure, consisting of 55 cells and input and output couplers is analyzed. This structure operates with a 5π/6 phase advance per cell. Dispersive effects for this structure are more significant than for previously studied 2π/3 phase advance accelerating structures. Experimental results are compared with the theoretical model and excellent agreement is obtained for the propagation of an RF pulse through the structure.The shape of an RF pulse is distorted upon propagating through an X-band accelerator structure due to dispersive effects. This distortion together with beam loading introduce energy spread between 192 bunches. In order to minimize this energy spread we modify the input RF pulse shape. The pulse propagation, energy gain, and beam loading are modelled with a mode-matching computer code and a circuit model. A 2D model and a circuit model of a complete 60 cm structure, consisting of 55 cells and input and output couplers is analyzed. This structure operates with a 5π/6 phase advance per cell. Dispersive effects for this structure are more significant than for previously studied 2π/3 phase advance accelerating structures. Experimental results are compared with the theoretical model and excellent agreement is obtained for the propagation of an RF pulse through the structure. 1 Work supported by the U.S. DOE Contract No. DE-AC03-76SF00515.
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