1.Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
2.University of Chinese Academy of Sciences, Beijing 100049, China
3.Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
Corresponding author, guqiang@sinap.ac.cn
Corresponding author, minghuazhao@sinap.ac.cn
Scan for full text
Kui Liu, Lin Li, Cheng Wang, et al. Multi-port cavity model and Low-level RF Systems design for VHF gun. [J]. Nuclear Science and Techniques 31(1):8(2020)
Kui Liu, Lin Li, Cheng Wang, et al. Multi-port cavity model and Low-level RF Systems design for VHF gun. [J]. Nuclear Science and Techniques 31(1):8(2020) DOI: 10.1007/s41365-019-0711-2.
Very high frequency (VHF) photocathode guns have excellent performance and are being increasingly selected as electron sources for high repetition rate X-ray free-electron lasers. As a high loaded quality factor cavity, the VHF gun requires high stability in the amplitude and phase of the cavity field. However, the gun is microwave powered by two solid-state power sources through two separate power couplers. The input difference between the two power couplers will influence the stability of the cavity field. To systematically study this influence and obtain measurement formulae, a multi-port VHF gun LCR circuit model is built and analyzed. During the warm-up condition, the cavity structure will be deformed due to the large-scale change in the cavity temperature. Then, the deformation will result in cavity resonant frequency changes. To prevent the mechanic tuner from suffering damages due to the frequent and long-distance movement for correcting the cavity resonant frequency, a self-excited loop (SEL) control system is considered for changing the loop phase and make the loop frequency follow the resonant frequency. In this study, a steady-state model of the VHF gun cavity is built for obtaining the optimal input coupler coefficient and the stability requirement of the forward voltage. Then, the generator-driven resonator (GDR) and SEL control system, which combine with the VHF multi-port modeling, are modeled and simulated. The simulated results show that the SEL system can perfectly operate in the process of condition and warm-up.
VHF photocathode gunMulti-port modelingSelf-excited loopLLRF control
F. Sannibale, D. Filippetto, C.F. Papadopoulos et al., Advanced photoinjector experiment photogun commissioning results. Phys. Rev. Spec. Top.-Ac. 15, 103501 (2012). https://doi.org/10.1103/PhysRevSTAB.15.103501https://doi.org/10.1103/PhysRevSTAB.15.103501
F. Sannibale, B. Bailey, K. Baptiste et al., Status of the APEX project at LBNL, Paper Presented at the 5th International Particle Accelerator Conference, (Dresden, Germany, 15-20 June 2014)
J.F. Schmerge, A. Brachmann, D. Dowell et al., The LCLS-II injector design, Paper Presented at the 36th International Free Electron Laser Conference, (Basel, Switzerland, 25-29 Aug. 2014)
R. Huang, D. Filippetto, C.F. Papadopoulos et al., Dark current studies on a normal-conducting high-brightness very-high-frequency electron gun operating in continuous wave mode, Phys. Rev. Spec. Top.-Ac. 18, 013401 (2015). https://link.aps.org/doi/10.1103/PhysRevSTAB.18.013401https://link.aps.org/doi/10.1103/PhysRevSTAB.18.013401
G. Huang, K. Campbell, L. Doolittle et al., LCLS-II gun/buncher LLRF system design, Paper Presented at the 9th International Particle Accelerator Conference, (Vancouver, Canada, 29 April-4 May 2018)
H.J. Qian, M. Krasilnikov, F. Stephan, A cryocooled normal-conducting and superconducting hybrid CW photoinjector, Paper Presented at the 38th International Free Electron Laser Conference, (Santa Fe, USA, 20-25 Aug. 2017)
S. Noguchi, E. Kako, M. Sato et al., KEK ERL cryomodule development, Paper Presented at the 50th ICFA Advanced Beam Dynamics Workshop on Energy Recovery Linacs, (New York, USA, 8-12 June 2009)
K. Watanabe, S. Noguchi, E. Kako et al., Development of the superconducting RF 2-cell cavity for the cERL injector at KEK. Nucl. Instrum. Meth. A 714, 67 (2013). https://doi.org/10.1016/j.nima.2013.02.035https://doi.org/10.1016/j.nima.2013.02.035
A. Neumann, M. Abo-Bakr, W. Anders et al., Booster cavity and fundamental power coupler design issues for bERLinPro, Paper Presented at the 5th International Particle Accelerator Conference, (Dresden, Germany, 15-20 June 2014)
M.D. Li, Y.B. Zhao, X. Zheng, et al., Design and implementation of frequency tracking and amplitude-phase feedback in RFQ low level control system, Nucl. Tech., 41, 060202(2018).https://doi.org/10.11889/j.0253-3219.2018.hjs.41.060202https://doi.org/10.11889/j.0253-3219.2018.hjs.41.060202 (in Chinese)
Z. Fang, T. Kobayashi, Y. Fukui et al., Auto-tuning systems for J-PARC LINAC RF cavities, Nucl. Instrum. Meth. A 767, 135 (2014). https://dx.doi.org/10.1016/j.nima.2014.08.014https://dx.doi.org/10.1016/j.nima.2014.08.014
J. Delayen, Self-ecxited loop. Jefferson lab LLRF workshop. https://www.jlab.org/intralab/calendar/archive01/LLRF/Delayen.pdfhttps://www.jlab.org/intralab/calendar/archive01/LLRF/Delayen.pdf.. Accessed 25 April 2001
T. Allison, J. Delayen, C. Hovater et al., A digital self excited loop for accelerating cavity field control, Paper Presented at the 2007 IEEE Particle Accelerator Conference, (Albuquerque, USA, 25-29 June 2007)
J. Delayen, Phase and amplitude stabilization of superconducting resonators, Ph. D. Thesis, California Institute of Technology, 1978.
S. Simrock, Achieving phase and amplitude stability in pulsed superconducting cavities, Paper Presented at the 2001 Particle Accelerator Conference, (Chicago, USA, 18-22 June 2001)
C. Hovater, P. Chevtsov, J. Delayen, RF system development for the CEBAF energy upgrade, Paper Presented at the proceedings of LINAC 2002, (Gyeongju, Korea, 19-23 Aug. 2002)
C. Hovater, RF control of high QL superconducting cavities, Paper Presented at the proceedings of LINAC 2008, (Victoria, Canada, 29 Sep. - 3 Oct. 2008)
T. Schilcher, Vector sum control of pulsed accelerating fields in lorentz force detuned superconduncting cavities, Ph. D. Thesis, Universitt Hamburg, 1998.
A. Sun, H.P. Wang, Superconducting RF cavity measurement formulae for an exponential decayed pulse incident power, Paper Presented at the 12th International Workshop On RF Superconductivity, (New York, USA, 10-15 Jul 2005)
L. Chen, S.H. Zhang, M.Y. Li et al., Room-temperature test system for 162.5 MHz high-power couplers. Nucl. Sci. and Tech. 30, 7 (2019). https://doi.org/10.1007/s41365-018-0531-9https://doi.org/10.1007/s41365-018-0531-9
W.B. Wu, K. Xuan, W. Xu et al., Development of a control system for the fourth-harmonic cavity of the HLS storage ring. Nucl. Sci. and Tech. 29, 153 (2018). https://doi.org/10.1007/s41365-018-0497-7https://doi.org/10.1007/s41365-018-0497-7
F. Qiu, S. Michizono, T. Miura et al., Real-time cavity simulator-based low-level radio-frequency test bench and applications for accelerators, Phys. Rev. Spec. Top. Accel. Beams 21, 032003 (2018). https://doi.org/10.1103/PhysRevAccelBeams.21.032003https://doi.org/10.1103/PhysRevAccelBeams.21.032003
S.S. Sun, J.Q. Zhang, L. Li, et al., Linearization of the input and output characteristic curve of a klystron for SXFEL, Nucl. Tech., 40, 060102 (2017).https://doi.org/10.11889/j.0253-3219.2017.hjs.40.060102https://doi.org/10.11889/j.0253-3219.2017.hjs.40.060102 (in Chinese)
S. Li, J.Q. Zhang, M. Zhang, et al., Implementation of FPGA-based feedforward function in LLRF system for electron LINAC, Nucl. Tech., 39, 070402 (2016).https://doi.org/10.11889/j.0253-3219.2016.hjs.39.070402https://doi.org/10.11889/j.0253-3219.2016.hjs.39.070402 (in Chinese)
G. Joshi, P. Singh, V. Agarwal et al., Digital self-excited loop for a superconducting linac, Nucl. Instrum. Meth. A 762, 70 (2014). https://dx.doi.org/10.1016/j.nima.2014.05.115https://dx.doi.org/10.1016/j.nima.2014.05.115
0
Views
0
Downloads
0
CSCD
Publicity Resources
Related Articles
Related Author
Related Institution