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C-band and X-band Activities at SINAP

C-band and X-band Activities at SINAP. Wencheng Fang, Qiang Gu, Chaopeng Wang, Jianhao Tan, Zhentang , Zhao, SINAP Dechun Tong, THU Xing Sheng , Lifang Chen, CETC 04 Feb, 2014, CLIC Workshop 2014. Background C-band activities Prototype accelerating structure

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C-band and X-band Activities at SINAP

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  1. C-band and X-band Activities at SINAP Wencheng Fang, Qiang Gu, Chaopeng Wang, Jianhao Tan, Zhentang, Zhao, SINAP Dechun Tong, THU Xing Sheng, Lifang Chen, CETC 04 Feb, 2014, CLIC Workshop 2014

  2. Background C-band activities Prototype accelerating structure New accelerating structure 1.8m accelerating structure for SXFEL Pulse compressor High power unit X-band activities Accelerating structure Deflecting cavity Workshop conclusion Outline

  3. Background (Shanghai Photon Science Center) 580m Compact XFEL SXFEL

  4. Brief layout of SXFEL and HXFEL Shanghai Soft X-ray FEL (2014) 8 C-band accs for 4 units X-band acc Compact hard X-ray FEL X-band 65MV/m for 150m linac

  5. Activities of C-band at SINAP

  6. 53 cells+2 matching cells Prototype of C-band Acc • Scheme: • Frequency: 5712MHz; • Length: about 1m; • Mode: 2pi/3, Disk-loaded; • Structure: Constant Impedance; • Group velocity: 1%*c; • Mode launch coupler; • No. of cells：53 regular cells and 2 matching cells.

  7. Cold test Mostly ±1 degree Partially ±2 Degree

  8. High power test results • For 40 MV/m, 20MW is required. However there is only 8MW output as the high power commissioning. So only about 20MV/m peak gradient is carried out. • Several breakdowns happen as input power is increased, and then approach to be stable soon. NOV. 23 8MW@170W pre-amplifier

  9. a The new C-band structure (4pi/5) • Short Range Wakefield • T-SWR is about 1/6. • L-SWR is about ½. • Group velocity is increased. • Peak field is also increased. Peak field and shunt impedance Phase Advance per cell Rs increased 10%

  10. New structure model 1. Compact mode launch coupler 2. Round cell 3. Constant gradient 4. High impedance 5. Inner water cooling

  11. Cold test results @ 5713MHz S11=-36dB@5713MHz 5712MHz of high power test

  12. The 1.8m C-band accelerating structure (2014) • Two structures is being machined in Beijing, and plan to make 2 structure in the middle of 2014 • 40MV/m@70MW, 0.5μs are required for the XFEL facility. • They compose one unit of beam acceleration.

  13. Pulse compressor (2014) Q=146997 f=5712MHz

  14. Layout of C-band acceleration unit (2014) LLRF Feedback, Feedforward Set point …… A/D D/A 500W，2.5us 5712MHz signal Pre-amplifier 160MW，0.5us 50MW，2.5us E37202 50MW，2.5us Also for the prototype and new experimental structure test. Many experiments will be taken in this setup. Oil tank SLED. 3.2 power multiplier Load 3dB divider Load 75MW，0.5us Load 75MW，0.5us 1.6m×40MeV/m=64MeV Unit length=4m，Energy:130MeV

  15. Considerations for X-band Accelerating structure Large iris aperture is required, and lower group velocity is also required. Making comparison among different modes. a=3.94mm, λ=26.25mm, a/λ=0.15 Considering feasible input power 80MW/m (maximum), input cell is selected carefully. 1. 65MV/m is required for the minimum gradient for 6.4GeV, which realizes linac less than 150 meters. 2. 80MV/m is used for energy updating to 8GeV in the future. 3. 2.6% group velocity/c is maximum value achieved below 80MW, and 65MV/m is located at 50MW. 4. Group velocity can be distributed from 2.6% to 1.4% for 1.0 m length.

  16. X-band Accelerating structure (coupler) Mode launch coupler No Dipole Low peak field However Quadrupole field Magnetic coupler with racetrack No Dipole, no quadrupole field However high peak field )

  17. X-band Accelerating structure (Mode launch coupler) R=1mm R=3mm Export E-field data along cycle curves (r=1, 2, 3mm), centered on axis. No other component but quadrupole. 1% quadrupole maximum for r=1mm 5% quadrupole maximum for r=3mm

  18. X-band Accelerating structure (Draft design)

  19. X-band deflecting cavity (2014) The coupler and cells are simulated and designed by CST

  20. Dedicated workshop for RF R&D at SINAP Tuning Milling 3D Vision Measuring Machine ZYGO DynaFiz dynamic laser interferometer 3D measuring machine ZeGage Optical surface profile Vacuum furnace Baking Water treatment for cleaning room

  21. C-band technology has been developing for many years at SINAP, including accelerating structure, pulse compressor and other components. In 2014, new power test setup will be installed, and condition several different C- band structures, and it will run at 40MV/m for SXFEL. Based on the RF research experience, X-band high gradient accelerating structure is being developed for new option of future compact FEL at SINAP, and 65MV/m is required for 150m 6.5GeV linac. The prototype is planed to fabricate in 2014, and we hope to condition it in 2014, or in the beginning of 2015. X-band deflecting cavity is also planed to be finished in 2014. For supporting RF R&D, new dedicated workshop has been already constructed at SINAP. Conclusion

  22. Thanks for your attention!!

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