• M.A. Green, A.J. DeMello, D. Li, F. Trillaud, S.P. Virostek, M.S. Zisman
  LBNL, Berkeley, California
• X.L. Guo, S.Y. Li, H. Pan, L. Wang, H. Wu, S.X. Zheng
  ICST, Harbin

Tests of the spectrometer solenoids have taught us some important lessons. The spectrometer magnet lessons learned fall into two broad categories that involve the two stages of the coolers that are used to cool the magnets. On the first spectrometer magnet, the problems were centered on the connection of the cooler 2nd-stage to the magnet cold mass. On the second spectrometer magnet, the problems were centered on the cooler 1st-stage temperature and the connections between leads, the cold mass support intercept, and the shields to the cooler first-stage. If the cooler 1st-stage temperature is too high, the refrigerator will not produce full 2nd stage cooling. If the 1st-stage temperature is too high, the temperature of the top of the HTS leads. As a result, more heat goes into the 4 K cold mass and the temperature margin of the top of the HTS leads is too small, which are in a magnetic field. The parameters that affect the magnet cooling are compared for the MICE coupling magnet and the spectrometer magnet.

• S.X. Zheng, X. Guan, J. Wei, H.Y. Zhang
  TUB, Beijing
• J.H. Billen, L.M. Young
  TechSource, Santa Fe, New Mexico
• J. Li, D.-S. zhang
  NUCTECH, Beijing
• J.H. Li
  CIAE, Beijing
• J. Stovall
  CERN, Geneva
• Y.L. Zhao
  IHEP Beijing, Beijing

The Compact Pulsed Hadron Source (CPHS) has launched at Tsinghua University to develop a university neutron source based on a 13 MeV, 50 mA proton linac which consists of ECR ion source, LEBT, RFQ and DTL. The primary design of the DTL for the CPHS is presented in this paper, which includes the dynamics calculation, RF field optimization and error analysis. This DTL can accelerate 50 mA proton beam from 3MeV to 13 MeV with 1.2 MW RF power input. The DTL is directly connected after RFQ without Medium-Energy Beam-Transport line (MEBT). PMQs are adopted in drift tubes focusing. The magnetic field gradient of PMQs are programmed to match the transverse restoring forces at the end of the RFQ to avoid missmatch and avoid parametric resonances.

• 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.

• Q.Z. Xing, Y.J. Bai, J.C. Cai, C. Cheng, T. Du, X. Guan, J. Wei, Z.F. Xiong, H.Y. Zhang, S.X. Zheng
  TUB, Beijing
• J.H. Billen, J. Stovall, L.M. Young
  TechSource, Santa Fe, New Mexico
• W.Q. Guan, Y. He, J. Li
  NUCTECH, Beijing

The design progress of the Radio Frequency Quadrupole (RFQ) accelerator for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University is presented in this paper. The RFQ will accelerate protons from 50 keV to 3 MeV, with the RF frequency of 325 MHz. The objective is to obtain the optimum structure of the RFQ accelerator with high transmission rate and tolerable total length. The beam dynamics are studied by the simulation of the proton beam in the RFQ accelerator with the code of PARMTEQM. The output proton beam from the RFQ is well matched into the DTL without Medium-Energy-Beam-Transport (MEBT) between the RFQ and DTL.

* K.R. Crandall et al., RFQ Design Codes, LA-UR-96-1836.

• C. Cheng, J.S. Duo, J. Lv, S.X. Zheng
  TUB, Beijing
• J. Li
  CAEP/IFP, Mainyang, Sichuan

Mini-LIA was a miniature linear induction accelerator designed and manufactured by China Academy of Engineering Physics and Tsinghua University. To investigate the higher order mode (HOM) of Mini-LIA cavity, especially the frequency and quality factor Q of the TM110 and TM120 in it, both numerical simulation and experiments were performed. Several models of the cavity were established and calculated by using E module of MAFIA code. Network analyzer was applied to measure the frequency and Q in cavity. Both the simulation results and the experiment results are presented in this paper. The results of the experiments were coincident with the calculated results. Finally, The HOM characteristic of Mini-LIA cavity with metglass core in it was explored, and some interesting results was obtained.

• 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.