THO2A  —  Beam Material Interaction   (30-Sep-10   09:00—10:20)

Chair: R. Schmidt, CERN, Geneva

Paper Title Page
THO2A01 Design of the T2K Target for a 0.75-MW Proton Beam 560
 
  • C.J. Densham, M. Baldwin, M.D. Fitton, M.T. Rooney, M.L. Woodward
    STFC/RAL, Chilton, Didcot, Oxon
  • A. Ichikawa
    Kyoto University, Kyoto
  • S. Koike, T. Nakadaira
    KEK, Ibaraki
 
 

The T2K experiment began operation in April 2009. It utilises what is projected to become the world’s highest pulsed power proton beam at 0.75 MW to generate an intense neutrino beam. T2K uses the conventional technique of interacting the 30 GeV proton beam with a graphite target and using a magnetic horn system to collect pions of one charge and focus them into a decay volume where the neutrino beam is produced. The target is a two interaction length (900 mm long) graphite target supported directly within the bore of the first magnetic horn which generates the required field with a pulsed current of 320 kA. The talk will describe the design and development of the target system, the beam windows and the beam absorber required to meet the demanding requirements of the T2K facility. Challenges include radiation damage, stress waves, design and optimisation of the helium coolant flow, and integration with the pulsed magnetic horn. Conceptual and detailed engineering studies were required to develop a target system that could satisfy these requirements and could also be replaced remotely in the event of failure.

 

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THO2A02 Beam Dump Development for the Korean Proton Accelerator 563
 
  • C.S. Gil, J.-H. Jang, D.H. Kim, J.H. Kim
    KAERI, Daejon
 
 

A beam dump for 20 MeV, 4.8mA proton beam had been manufactured in KAERI. The 20 MeV beam dump was made of graphite to reduce radioactivity by the materials around the beam dump as well as the beam dump itself. The beam dump was designed to by placing two plates of 30 cm by 60 cm at an angle of 12 degree. The IG430 graphite and OFHC copper were brazed with TiCuSil filler metal for cooling. The proton beam was assumed to be expanded for the peak heat flux in the graphite to be less than 200 W/cm2. The beam dump designed for maximum temperatures of graphite, copper and cooling water to be less than 223, 146 and 85 celsius degrees, respectively. The activation analysis of the beam dump was also performed with MCNP code. The sensitivity analyses of graphite tensile stresses to optimize the thicknesses of graphite with copper brazing were performed with ANSYS code. The tensile stress of graphite during the brazing process was the smallest around 1 cm thickness of graphite. A 100 MeV proton beam dump was designed with copper. The optimal angles between two copper plates for the minimum peak heat fluxes are 10~20 degrees. The peak heat flux in the copper plates at 15 degree is 333 W/cm2.

 

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THO2A03 New Design of a Collimator System at the PSI Proton Accelerator 567
 
  • Y. Lee, P. Baumann, V. Gandel, D.C. Kiselev, D. Reggiani, M. Seidel, A. Strinning, S. Teichmann
    PSI, Villigen
 
 

PSI is gradually upgrading the 590 MeV proton beam intensity from the present 2.2 mA towards 3 mA, which poses a significant challenge to the reliable operation of the accelerator facility. Of particular concern is the collimator system which is exposed to the dispersed beam from a muon production target. It shapes an optimal beam profile for low-loss beam transport to the neutron spallation source SINQ. The collimator system absorbs slightly more than 10 % of the proton beam power and the maximum temperature of the collimator system exceeds 350 C at 2.2 mA, which is close to the failure point. In this paper, we present a new collimator system design which could withstand the proton beam intensity of 3 mA, while fulfilling the intended functionalities. Advanced multi-physics simulation technology is used for the geometric and material optimizations, to achieve the lowest possible actual to yield stress ratio at 3 mA. A sensitivity study is performed on the correlation between the beam misalignments and the reliability of the key accelerator components in the proton downstream region. Also reported are the possible proton irradiation effects on the mechanical failure criteria.

 

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THO2A04 The Design of Beam Collimation System for CSNS/RCS 572
 
  • N. Wang, N. Huang, Q. Qin, S. Wang
    IHEP Beijing, Beijing
 
 

China Spallation Neutron Source (CSNS) accelerator consists of a 80 MeV linac and a 1.6 GeV Rapid Cycling Synchrotron (RCS), which is designed to produce beam power of 100 kW with a repetition rate of 25 Hz. For such a high intensity RCS, beam loss and control are of primary concern. A two-stage collimation system is designed to localize the beam losses in a restricted area, and keep the uncontrolled losses less than 1 W/m at the other part of RCS. The detailed design of the beam collimation system is presented, including the compare among different schemes. Key issues which affect the collimation efficiency are analyzed, and the collimation efficiency and beam loss distributions are studied by using the code ORBIT.

 

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