• 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.

• L.J. Mao, G.H. Li, J. Li, J.W. Xia, J.C. Yang, X.D. Yang, Y.J. Yuan
  IMP, Lanzhou

Two electron cooling devices have been used at HIRFL-CSR in order to provide high quality heavy ion beams for nuclear and atomic research. The momentum spread is one of the most important characteristics of the beam quality. At HIRFL-CSR, the momentum spread is measured directly with the aid of longitudinal Schottky spectra system. In this paper, the measurements for various ion species are presented. At relatively high intensity, longitudinal Schottky spectra is double peak due to collective phenomena and the momentum spread can be obtained by fitting the spectra. The dependence of momentum spread on stored particle number is proportional to N**a. Moreover, the heating factor was investigated after switching off the electron cooling. The residual gas scattering, the intrabeam scattering and instabilities are studied according to the measured data.

• 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.

• 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.