• H. Chen, Q.X. Jin, R.K. Li, Y. Z. Lin
  TUB, Beijing
• J. Gao
  Tsinghua University, Beijing

The method of intensity-modulated radiotherapy (IMRT) is increasingly concerned by the medical world in recent years. Based on the performance characteristic of IMRT accelerator, a 6MeV S-band on axis-coupled SW, Suitable for IMRT, electron linear accelerating tube has been developed in Accelerator Lab of Tsinghua University. This paper provides the design performance characteristics of the tube and the results of the high-power tests,analyzes the performance and problems in the operation.

• Q.X. Jin, H. Chen, D.C. Tong
  TUB, Beijing

In this paper, the design of a C-band SW accelerating tube is presented and its high power test set is shown. The tube can accelerate electrons to 9 MeV or 6 MeV. Its length is about 620mm, and a Pierce electron gun is used. A 2.5MW pulsed magnetron at 5712 MHz is served as the tube's RF power source. Two energy modes are performed by changing the input RF power and the injecting voltage of electron gun.

• R.K. Li, H. Chen, Q. Du, T. Du, Y.-C. Du, Hua, J.F. Hua, W.-H. Huang, X. H. Lu, J. Shi, C.-X. Tang, H. S. Xu, L.X. Yan
  TUB, Beijing

Recent years have witnessed rapid advances of MeV ultrafast electron diffraction (UED), in which high quality, ultrashort, MeV electron pulses from a photocathode RF gun are employed as probes for ultrafast structural dynamics. We've built a prototype MeV UED system at the Accelerator Laboratory of Tsinghua University, optimized the the electron pulse parameters as well as hardware performances, and achieved high quality single-shot diffraction patterns. Moreover, MeV UED can be operated in a so-called 'continuously time-resolved (CTR)' mode, in which an RF deflecting cavity streaks the electron pulse thus each diffraction pattern constitutes an 'atomic movie'. We report our experimental progress on MeV UED in this paper.

• J.Q. Qiu, H. Chen, C.-X. Tang
  TUB, Beijing

For the miniaturization of low energy linear accelerators, X-band pulsed magnetron with stable performance of 1.5 MW peak power is needed to be developed. This paper presents the 3D particle-in-cell (PIC) of an X-band coaxial magnetron. A time evolved electron flow exhibits N/2 spokes in the simulations, which confirms the generation of pi-mode. Computer modeling indicates the mode competition in the startup process according to the spectra. By changing the DC voltage, we got the voltage-current characteristics of this magnetron, and comparison with the experiment was also been presented.

• J. Wei, Y.J. Bai, J.C. Cai, H. Chen, C. Cheng, Q. Du, T. Du, Q.X. Feng, Z. Feng, H. Gong, X. Guan, X.X. Han, T.C. Huang, Z.F. Huang, R.K. Li, W.Q. Li, C.-K. Loong, C.-X. Tang, Y. Tian, X.W. Wang, X.F. Xie, Q.Z. Xing, Z.F. Xiong, D. Xu, Y.G. Yang, Z. Zeng, H.Y. Zhang, X.Z. Zhang, S.X. Zheng, Z.H. Zheng, B. Zhong
  TUB, Beijing
• J.H. Billen, L.M. Young
  LANL, Los Alamos, New Mexico
• S. Fu, J. Tao, Y.L. Zhao
  IHEP Beijing, Beijing
• W.Q. Guan, Y. He, G.H. Li, J. Li, D.-S. zhang
  NUCTECH, Beijing
• J.H. Li
  CIAE, Beijing
• T.J. Liang
  Institute of Physics, Chinese Academy of Sciences, Beijing
• Z.W. Liu, L.T. Sun, H.W. Zhao
  IMP, Lanzhou
• B.B. Shao
  Tsinghua University, Beijing
• J. Stovall
  CERN, Geneva

This paper reports the design and construction status, technical challenges, and future perspectives of the proton-linac based Compact Pulsed Hadron Source (CPHS) at the Tsinghua University, Beijing, China.

• C.-J. Jing
  Euclid TechLabs, LLC, Solon, Ohio
• S.P. Antipov, M.E. Conde, W. Gai, F. Gao, J.G. Power, Z.M. Yusof
  ANL, Argonne
• H. Chen, C.-X. Tang, S.X. Zheng
  TUB, Beijing
• P. Xu
  Tsinghua University, Beijing

Wakefield excitation has been experimentally studied in a 3-cell X-band standing wave Photonic Band Gap (PBG) accelerating structure. Major monopole (TM01- and TM02-like) and dipole (TM11- and TM12-like) modes were indentified and characterized by precisely controlling the position of beam injection. The quality factor Q of the dipole modes was measured to be ~10 times smaller than that of the accelerating mode. A charge sweep, up to 80 nC, has been performed, equivalent to ~30 MV/m accelerating field on axis. A variable delay low charge witness bunch following a high charge drive bunch was used to calibrate the gradient in the PBG structure by measuring its maximum energy gain and loss. Experimental results agree well with numerical simulations.