• Y. He, W. Chang, X. Du, Y. Ma, L.P. Sun, Z.J. Wang, J.W. Xia, C. Xiao, Y.Q. Yang, S.H. Zhang, Z.L. Zhang, H.W. Zhao
  IMP, Lanzhou
• J.E. Chen, M. Kang, Y.R. Lu, Q.F. Zhou, K. Zhu
  PKU/IHIP, Beijing

Heavy Ion Research Facility at Lanzhou (HIRFL) consists of two cyclotrons (SFC and SSC), one synchrotron (CSRm), and one storage ring (CSRe). The two cyclotrons are in series as the injector of the synchrotron. An additional LINAC injector for SSC is considered to increase the beam time at targets. The new injector consists of an RFQ and four IH-DTL tanks. A pre-buncher in the front of RFQ is 13 MHz to match the RF frequency of SSC. The LINAC can operate in two modes. In the first mode, the middle-mass ions output with energy of 0.54 MeV/u, and then SSC accelerates them up to the energy of 5.62 MeV/u. The beam is used to do the Super Heavy Elements (SHE) experiments. In the second mode, the very heavy ions output with energy of 0.97 MeV/u, and then SSC accelerates them up to energy of 10.06 MeV/u. The beam is injected into CSRm after stripped. Code LINREV and DAKOTA are used to design and optimize the acceleration structures of DTLs. The energy spread less than ±0.5% and bunch length less than 2.6 ns are achieved at the exit of the last tank. These can match the ideal acceptance of SSC. A simulation from LEBT to exit of DTL is done by Beampath to benchmark the design.

* All authors belong to PKU-IMP RF LINAC Research Center for Heavy Ions.

• Y. Liu, X. Du, X.H. Guo, Y. He, S. Sha, A. Shi, L.P. Sun, Z. Xu, W.-L. Zhan, H. Zhao
  IMP, Lanzhou
• R.A. Jameson, A. Schempp, M. Vossberg, H. Zimmermann
  IAP, Frankfurt am Main
• M. Okamura
  BNL, Upton, Long Island, New York

A compact RFQ for carbon ion beam from a Laser-ion souce is being tested in IMP, Lanzhou. It is the first example of LINAC structures for IMP. Testing schemes and first results are presented.

• Z.L. Zhang, X.H. Guo, Y. He, Y. Liu, S. Sha, A. Shi, L.P. Sun, H.W. Zhao
  IMP, Lanzhou
• R.A. Jameson, A. Schempp
  IAP, Frankfurt am Main
• M. Okamura
  BNL, Upton, Long Island, New York

A RFQ has been designed and built for research of direct plasma injection scheme (DPIS), which can provide high current and highly charged beams. Because of the strong space charge forces of beam from laser ion source, the beam dynamics design of the RFQ was carried out with a new code LINACSrfq which can treat space charge effectively due to equipartitioning design strategy. Another feature of the RFQ is its high energy gain in two-meter long which will be described in detail. Construction of the RFQ cavity and the 100MHz/250kW amplifier has been completed and ready for test. A laser ion source is being tested. The assembling of the whole system including the ion source, the RFQ, the beam analyzing and diagnostic system is being done. Preliminary test results will be presented.

• Z.J. Wang, Y. He, W. Wu, C. Xiao, Y.Q. Yang
  IMP, Lanzhou

The separated function DTL in SSC(Separated Sector Cyclotron)-linac is being designed. According to the design requirements, 238U³⁴⁺ ions are accelerated from 0.143MeV/u to 0.976MeV/u throught the DTL. The method coupling DAKOTA(Design Analysis Kit for Optimization and Terascale Application) and beam simulation code BEAMPATH is used to analyze tolerance of the structure. The tolerance of beam parameters to various type of random errors and misalignment are studied with Monte Carlo simulation,so as to dene the engineering tolerance and alignment. In this paper, the beam dynamics simulation and the tolerance analysis of the SSC-linac are presented.

• Q.Z. Xing, Y.J. Bai, J.C. Cai, X. Guan, X.W. Wang, J. Wei, Z.F. Xiong, H.Y. Zhang
  TUB, Beijing
• J.H. Billen, L.M. Young
  LANL, Los Alamos, New Mexico
• W.Q. Guan, Y. He, J. Li
  NUCTECH, Beijing
• J. Stovall
  CERN, Geneva

We present, in this paper, the physics and mechanical design of a Radio Frequency Quadrupole (RFQ) accelerator for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. The 3-meter-long RFQ will accelerate protons from 50 keV to 3 MeV at an RF frequency of 325 MHz. In the physics design we have programmed the inter-vane voltage as a function of beam velocity, to optimize the performance of the RFQ, by tailoring the cavity cross section and vane-tip geometry as a function of longitudinal position while limiting the peak surface electric field to 1.8 Kilpatrick. There will be no Medium-Energy-Beam-Transport (MEBT) following the RFQ. The focusing at the high energy end of the RFQ and at the entrance of the DTL have been tailored to provide continuous restoring forces independent of the beam current. In simulations of the proton beam in the RFQ, using the code PARMTEQM, we observe transmission exceeding 97%. The RFQ is mechanically separated into three sections to facilitate machining and brazing. We have machined a test section and the final RFQ accelerator is now under construction. We will describe the status of the RFQ system in this paper.

* 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
• Y. He, J. Li, D.-S. zhang
  NUCTECH, Beijing
• J.H. Li
  CIAE, Beijing
• J. Stovall
  CERN, Geneva
• Y.L. Zhao
  IHEP Beijing, Beijing

The CPHS project in Tsinghua University plans to construct a 13 MeV linear accelerator to deliver a pulsed proton beam having an average beam current of 2.5 mA. A Drift Tube Linac (DTL), following a Radio Frequency Quadrupole accelerator(RFQ), will accelerate protons from 3 to 13MeV. The accelerating field and phase will be ramped to match the longitudinal restoring forces at the end of the RFQ. Likewise, the transverse focusing forces, provided by permanent-magnet quadrupole lenses (PMQs) will be programmed to match the transverse restoring forces at the end of the RFQ to avoid missmatch and avoid parametric resonances. We will present the main physics design parameters of CPHS DTL and describe the properties of the resonant cavity. We plan to apply electron beam welding technology exclusively in the fabrication of the drift tubes and will present the test results from our engineering prototyping program.