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hadron

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MO101 J-PARC Project neutron, kaon, linac, proton 1
 
  • S. Nagamiya
    KEK, Ibaraki
 
 

About ten years ago (2001) a new accelerator project to provide high-intensity proton beams proceeded into its construction phase. This project is called the J-PARC (Japan Proton Accelerator Research Complex), and it was completed about a year ago in 2009. The construction was performed under a cooperation of two institutions, KEK and JAEA. The goal of the accelerator power is 1 MW proton beams at 3 GeV, with 400 MeV Linac injector, and 0.75 MW beams at 50 GeV. Three experimental facilities are presently available: 1) the Materials and Life Experimental Facility where pulsed neutrons and muon beams from 3 GeV are produced and utilized, 2) the Hadron Experimental Facility where kaon beams are produced, with a slow extraction mode from the 50 GeV (currently, 30 GeV is used), and 3) the Neutrino Experimental Facility with fast extraction mode from the 50 GeV ring. I would like to review the current status of the accelerators and experimental facilities, in particular, under the emphasis of what are actually going on in regard experimental programs. I also would like to mention a future scope of the J-PARC.

 
TUP036 The RF System for the Compact Pulse Hadron Source klystron, rfq, DTL, linac 479
 
  • C. Cheng, T. Du, X. Guan, J. Wei, S.X. Zheng
    TUB, Beijing
 
 

The Compact Pulsed Hadron Source (CPHS) system has been proposed and designed by the Department of Engineering Physics of Tsinghua University in Beijing, China. It consists of an accelerator front-end'a high-intensity ion source, a 3 MeV radiofrequency quadrupole linac (RFQ), and a 13 MeV drift-tube linac (DTL), a neutron target station, and some experimental stations. In our design, both RFQ and DTL share a single klystron which is capable of 2.5 MW peak RF power and a 3.33% duty factor. The 325 MHz klystron contains a modulating anode and has a 100 kW average output power. Portions of the RF system, such as pulsed high voltage power source, modulator, crowbar protection and RF transmission system are all presented in details in this paper.

 
TUP046 Development of the 3MeV RFQ for the Compact Pulsed Hadron Source at Tsinghua University rfq, cavity, DTL, vacuum 509
 
  • 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.

 
THP037 High-Gradient Test of a 3 GHz Single-Cell Cavity cavity, linac, ion, RF-structure 839
 
  • S. Verdú-Andrés, U. Amaldi, R. Bonomi, A. Degiovanni, M. Garlasché
    TERA, Novara
  • A. Garonna
    EPFL, Lausanne
  • C. Mellace, P. Pearce
    A.D.A.M. S.A., Geneva
  • S. Verdú-Andrés
    IFIC, Valencia
  • R. Wegner
    CERN, Geneva
 
 

Proton and carbon ion beams present advantageous depth-dose distributions with respect to X-rays. Carbon ions allow a better control of "radioresistant" tumours due to their higher biological response. For deep-seated tumours proton and carbon ion beams of some nA and energies of about 200 MeV and 400 MeV/u respectively are needed. For these applications TERA proposed the "cyclinac": a high-frequency linac which boosts the hadrons accelerated by a cyclotron. The dimensions of the complex can be reduced if higher accelerating gradients are achieved in the linac. To test the maximum achievable fields, a 3 GHz cavity has been built by TERA. The 19 mm-long cell is foreseen to be excited at 200 Hz by 3 us RF pulses and should reach a 40 MV/m accelerating gradient, which corresponds to a peak surface electric field Es of 260 MV/m. In a first high-power test performed at CTF3 the cell was operated at 50 Hz with a maximum peak power of 1 MW. The maximum Es achieved was above 350 MV/m. The breakdown rate at these field values was around 10-1 bpp/m. The maximum value of the modified Poynting vector is close to the best values achieved by high gradient structures at 12 and 30 GHz.