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Wang, J.-G.

Paper Title Page
MOPAS084 SNS Ring Extraction Septum Magnet and its Interference with Adjacent Quadrupole 626
 
  • J.-G. Wang
    ORNL, Oak Ridge, Tennessee
  
  Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U. S. Department of Energy under contract DE-AC05-00OR22725.

3D computing simulations have been performed to study the magnetic field distribution of the SNS ring extraction Lambertson septum magnet. The magnetic field for extracted beams is fully characterized in all the aspects. The stray field on the circulating beam line and the effect of a shielding box up-stream and a shielding cap down-stream is investigated. In addition, the magnetic interference between the Lambertson and an adjacent quadrupole has been studied. The simulations have provided valuable information for the SNS ring commissioning and operation. This paper reports our simulation techniques and the major results.

 
THPAS076 ORBIT Injection Dump Simulations of the H0 and H- Beams 3657
 
  • J. A. Holmes, M. A. Plum, J.-G. Wang, Y. Zhang
    ORNL, Oak Ridge, Tennessee
  • M. R. Perkett
    Denison University, Granville, Ohio
  
  Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U. S. Department of Energy under contract DE-AC05-00OR22725.

Simulations of the transport of H0 and H- beams to the SNS ring injection dump are carried out using the ORBIT code. During commissioning and early operations, beam losses in this region have been the highest in the accelerator and presented the most obvious hurdle to cross in achieving high intensity operation. Two tracking models are employed:

  1. a piecewise continuous symplectic representation of the lattice elements in the injection chicane and dump line, and
  2. particle tracking in full 3D magnetic fields, as obtained from OPERA code evaluations.
The physics models also include estimations of scattering from both the primary and secondary stripper foils, and beam losses due to apertures throughout the beam line. 		 
THPAS078 3D Modeling of SNS Ring Injection Dump Beam Line 3660
 
  • J.-G. Wang
    ORNL, Oak Ridge, Tennessee
  
  Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U. S. Department of Energy under contract DE-AC05-00OR22725.

The SNS ring injection dump beam line has been suffering high beam losses since its commissioning. In order to understand the mechanisms of the beam losses, we have built a 3D simulation model consisting of three injection chicane dipoles and one injection dump septum. The magnetic field distributions and the 3D particle trajectories in the model are obtained. The study has clearly shown two design problems causing beam losses in the injection dump beam line. This paper reports our simulation model, particle trajectory calculations, beam losses due to small vertical aperture of the injection dump septum and inadequate focusing down stream. The remedy of the beam losses is also discussed.