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Ko, K.

Paper Title Page
MOP104 Parallel 3D Finite Element Particle-In-Cell Code for High-Fidelity RF Gun Simulations 317
 
  • A.E. Candel, A.C. Kabel, K. Ko, L. Lee, Z. Li, C. Limborg-Deprey, C.-K. Ng, G.L. Schussman, R. Uplenchwar
    SLAC, Menlo Park, California
 
 

Funding: Work supported by DOE contract DE-AC02-76SF00515.
SLAC's Advanced Computations Department (ACD) has developed the first high-performance parallel Finite Element 3D Particle-In-Cell code, Pic3P, for simulations of rf guns and other space-charge dominated beam-cavity interactions. As opposed to standard beam transport codes, which are based on the electrostatic approximation, Pic3P solves the complete set of Maxwell-Lorentz equations and thus includes space charge, retardation and wakefield effects from first principles. Pic3P uses advanced Finite Element methods with unstructured meshes, higher-order basis functions and quadratic surface approximation. A novel scheme for causal adaptive refinement reduces computational resource requirements by orders of magnitude. Pic3P is optimized for large-scale parallel processing and allows simulations of realistic 3D particle distributions with unprecedented accuracy, aiding the design and operation of the next-generation of accelerator facilities. Applications to the Linac Coherent Light Source (LCLS) rf gun are presented.

 
THP039 SRF Cavity Imperfection Studies Using Advanced Shape Uncertainty Quantification Tools 870
 
  • V. Akcelik, K. Ko, L. Lee, Z. Li, C.-K. Ng, L. Xiao
    SLAC, Menlo Park, California
 
 

Funding: Work supported by DOE contract DE-AC02-76SF00515.
The shape deviation of a SRF cavity from the design shape may result in significant impact on cavity performance and wakefields that could lead to unexpected effects in beam dynamics. Yet, most of these deviations are unknown in the final cavity installation because of the complicated process of assembly and tuning. It is desirable to be able to uncover such distortions using measurable rf quantities. With these data, the cavity performance can be analyzed and realistic tolerance criteria may be implemented in the cavity design and manufacture for quality assurance. To perform such analyses, SLAC has developed advanced Shape Determination Tools, under the SciDAC support for high performance computing, that recover the real cavity shape by solving an inverse problem. These tools have been successfully applied to analyze shape distortions to many SRF cavities, and identified the cause of unexpected cavity behaviors. The capabilities and applications of these tools will be presented.