Author: Mao, L.J.
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TUXAUD04
 Conceptual Design of the HIAF Electron Cooling System  
 
  • L.J. Mao, W.P. Chai, J. Li, P. Li, X.M. Ma, G.D. Shen, L.N. Sheng, M.T. Tang, J.W. Xia, T.L. Yan, J.C. Yang, X.D. Yang, D.Y. Yin, Y.J. Yuan, H. Zhao
    IMP/CAS, Lanzhou, People's Republic of China
  
  A new accelerator complex HIAF is under design at IMP Lanzhou to provide intense primary and radioactive ion beams for nuclear physics, atomic physics and applied researches. The key parts of HIAF are the booster ring which is used to accumulated heavy ions and the spectrometer ring which can be used as platform for nuclear and atomic physics experiments. A magnetized electron cooling device is supposed to be used in the booster ring for decreasing the transverse emittance of injected beams. Meanwhile, a magnetized electron cooling device together with a ultra-low temperature electron target are also considered to be equipped in the spectrometer ring. In this paper, the conceptual design and main parameters of the electron cooling devices are presented, and the instabilities of cooled high intensity heavy-ion beams are discussed preliminarily.  
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TUYAUD03 Formation of Bunched Electron Beam at the Electron Cooler of CSRm 85
 
  • X.D. Yang, J. Li, X.M. Ma, L.J. Mao, M.T. Tang, T.L. Yan
    IMP/CAS, Lanzhou, People's Republic of China
  
  The motivation for formation of bunched electron beam at the electron cooler of CSRm is based on the three requirements. Firstly, the high energy electron cooling, especially, the ion beam with TeV energy, the bunched electron beam for cooling would be easier than the DC operating mode. Secondly, the electric field induced by the intensity modulated electron beam will be used for the suppression of instability developed in the high intensity ion beam after accumulation with the help of electron cooling, Thirdly, the electron beam was required to turn on and off in the different period of the atomic physics experiments. Some initial design and consideration were presented in this paper. And also the current situation and condition of CSRm electron cooler were described here. An off-line testbench will be established in the laboratory, and the test and the optimization will be explored in this experimentation. The validity of this system will be verified in the near future. The procedure of the modulation on the voltage of control electrode in the electron gun of the CSRm cooler was discussed. The scheme of off-line measurement was devised according to the progress.  
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TUPF03
 Test Experiment of Laser Cooling of Relativistic Li-Like C3+ Ion Beams With a Pulsed UV-Laser System at the CSRE*  
 
  • W.Q. Wen, X. Chuai, B. Hai, Z. Huang, J. Li, X. Ma, L.J. Mao, R.S. Mao, H. Wang, J.X. Wu, J.W. Xia, J.C. Yang, J. Yang, Y.J. Yuan, D. Zhang, D. Zhao, X. Zhu
    IMP/CAS, Lanzhou, People's Republic of China
  • G. Birkl, B. Rein, T. Walther
    TU Darmstadt, Darmstadt, Germany
  • O. Boine-Frankenheim, L. Eidam, D.F.A. Winters
    GSI, Darmstadt, Germany
  • M.H. Bussmann, M. Löser
    HZDR, Dresden, Germany
  • U. Schramm, M. Siebold
    Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
  • U. Schramm
    TU Dresden, Dresden, Germany
  
  Funding: * Work supported by NSFC No.11221064, GJHZ1305 and BMBF
A test experiment was performed with 12C3+ ion beams at an energy of 122 MeV/u on the CSRe in September 2014. A pulsed UV laser system from HZDR was employed for this test laser cooling experiment. The closed 2s1/2―2p1/2 optical transition at a wavelength of 155.07 nm of the Li-like carbon ions was Doppler-shifted to be resonant with the UV-laser at the wavelength of 257.5 nm in the experiment. The injected number of C3+ ~5×108,which was sufficient for testing laser cooling. Stable operation of the CSRe was observed over several days, including rf-bunching and diagnostic systems. The dynamics of the electron-cooled and RF-bunched ion beams were investigated systematically. However, first results did not yet indicate a strong interaction of the laser with the ions. Further data analysis is currently in progress. We will present the experimental results on this workshop, including Schottky spectra of electron-cooled and rf-bunched ion beams, fluorescence signals observed by the UV-sensitive PMT and CPM, and the planning of the upcoming laser cooling experiment at the CSRe.
# x.ma@impcas.ac.cn 		 
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TUPF11
 Progress in Experimental Demonstration of Cooling of Ions by a Bunched Electron Beam  
 
  • L.J. Mao, X.M. Ma, M.T. Tang, H. Zhao
    IMP/CAS, Lanzhou, People's Republic of China
  • A. Hutton, H. Wang, H. Zhang, Y. Zhang
    JLab, Newport News, Virginia, USA
  • V.V. Parkhomchuk, V.B. Reva
    BINP SB RAS, Novosibirsk, Russia
  
  Electron cooling is essential for achieving high luminosities for hadron colliders by enabling a reduction of emittance of hadron beams in storage rings. For several future projects such as low energy RHIC cooling program (LEReC) at BNL, a low energy electron-ion collider based on HIAF at IMP and a Medium energy Electron-Ion Collider (MEIC) at JLab, since the hadron beam energies are in a range from several GeV to 100 GeV, the required electron energy is up to 55 MeV. Such high energy electron beams can only be provided by a RF/SRF linac. As a result, the electron beam is highly bunched. Cooling of ions by a bunched electron beam has never been realized before, thus it becomes a critical R&D to these projects. Recently we proposed a proof-of-concept experiment to demonstrate cooling by a bunched electron beam utilizing an existing DC cooler at IMP. Here we present a progress report of this experiment. We briefly describe the experiment and show the design parameters. We then report hardware installation and results of the bench tests. We also summarize the results of the cooling simulation studies and discuss the required beam measurement capability.  
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THXCR04
 Status and Upgrade of HIRFL Accelerator Complex at IMP  
 
  • Y.J. Yuan, X.J. Hu, X.N. Li, X. Ma, L.J. Mao, J.X. Wu, J.W. Xia, J.C. Yang, W.Q. Yang, X.D. Yang, H.W. Zhao
    IMP/CAS, Lanzhou, People's Republic of China
  
  The Heavy Ion Research Facility at Lanzhou (HIRFL) is the only one large scale heavy ion accelerator complex that uses cyclotron(SFC and SSC) as injector, synchrotron(CSRm) for accumulation and post acceleration, storage ring(CSRe) for in ring experiments in China. To reach the increasing requirements from nuclear physics, atomic physics, interdisciplinary science and their applications, many upgrading plans were launched or scheduled. The present status and recent upgrading plans of HIRFL will be introduced in this paper. The operation of the electron coolers and related cooling experimental results are presented. For the upgrading plans, the development of new Linac injector for HIRFL and the new high voltage system of 300keV electron cooler will be discussed in details.  
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