PAC09 - List of Authors (Ko, K.)

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Ko, K.

Paper	Title	Page
WE5PFP020	Multipacting Simulation for Muon Collider Cavity	2033
	L. Ge, K. Ko, Z. Li, C.-K. Ng SLAC, Menlo Park, California D. Li LBNL, Berkeley, California R. B. Palmer BNL, Upton, Long Island, New York
	Funding: This work was supported by DOE contract No. DE-AC02-76SF00515 NERSC The muon cooling cavity for Muon Collider works under strong external magnetic fields. It has been observed that this external magnetic field can enhance the multipacting activities and dark current heating. As part of a broad effort to optimize external magnetic field map and cavity shape for minimal dark current and multipacting, we use SLAC’s 3D parallel code Track3P to analyze the multipacting and dark current issues of the design. Track3P has been successfully used to predict multipacting phenomena in cavity and coupler designs. It provides unprecedented capabilities for simulating large-scale accelerator structure systems, including realistic 3D details and low turn-around times. In this paper, we present the comprehensive multipacting and dark current simulations for Muon Collider cavities.
WE5PFP046	Dark Current Simulation for the CLIC T18 High Gradient Structure	2101
	Z. Li, A.E. Candel, L. Ge, K. Ko, C.-K. Ng, G.L. Schussman SLAC, Menlo Park, California S. Döbert, M. Gerbaux, A. Grudiev, W. Wuensch CERN, Geneva T. Higo, S. Matsumoto, K. Yokoyama KEK, Ibaraki
	Funding: This work was supported by DOE Contract No. DE-AC02-76SF00515 and used resources of NERSC supported by DOE Contract No. DE-AC02-05CH11231, and of NCCS supported by DOE Contract No. DE-AC05-00OR22725. Normal conducting accelerator structures such as the X-Band NLC structures and the CLIC structures have been found to suffer damage due to RF breakdown and/or dark current when processed to high gradients. Improved understanding of these issues is desirable for the development of structure designs and processing techniques that improve the structure high gradient performance. While vigorous experimental efforts have been put forward to explore the gradient parameter space via high power testing, comprehensive numerical multipacting and dark current simulations would complement measurements by providing an effective probe for observing interior quantities. In this paper, we present studies of multipacting, dark current, and the associated surface heating in high gradient accelerator structures using the parallel finite element simulation code Track3P. Comparisons with the high power test of the CLIC accelerator structures will be presented.
FR5PFP068	Wakefield Simulation of CLIC PETS Structure Using Parallel 3D Finite Element Time-Domain Solver T3P	4467
	A.E. Candel, A.C. Kabel, K. Ko, L. Lee, Z. Li, C.-K. Ng, G.L. Schussman SLAC, Menlo Park, California I. Syratchev CERN, Geneva
	Funding: This work was supported by DOE Contract No. DE-AC02-76SF00515 and used resources of NERSC supported by DOE Contract No. DE-AC02-05CH11231, and of NCCS supported by DOE Contract No. DE-AC05-00OR22725. In recent years, SLAC's Advanced Computations Department (ACD) has developed the parallel 3D Finite Element electromagnetic time-domain code T3P. Higher-order Finite Element methods on conformal unstructured meshes and massively parallel processing allow unprecedented simulation accuracy for wakefield computations and simulations of transient effects in realistic accelerator structures. Applications include simulation of wakefield damping in the Compact Linear Collider (CLIC) Power Extraction and Transfer Structure (PETS).
FR5PFP069	Parallel 3D Finite Element Particle-in-Cell Simulations with Pic3P	4470
	A.E. Candel, A.C. Kabel, K. Ko, L. Lee, Z. Li, C.-K. Ng, G.L. Schussman SLAC, Menlo Park, California I. Ben-Zvi, J. Kewisch BNL, Upton, Long Island, New York
	Funding: This work was supported by DOE Contract No. DE-AC02-76SF00515 and used resources of NERSC supported by DOE Contract No. DE-AC02-05CH11231, and of NCCS supported by DOE Contract No. DE-AC05-00OR22725. SLAC's Advanced Computations Department (ACD) has developed the parallel 3D Finite Element electromagnetic Particle-In-Cell code Pic3P. Designed for simulations of beam-cavity interactions dominated by space charge effects, Pic3P solves the complete set of Maxwell-Lorentz equations self-consistently and includes space-charge, retardation and boundary effects from first principles. Higher-order Finite Element methods with adaptive refinement on conformal unstructured meshes lead to highly efficient use of computational resources. Massively parallel processing with dynamic load balancing enables large-scale modeling of photoinjectors with unprecedented accuracy, aiding the design and operation of next-generation accelerator facilities. Applications include the LCLS RF gun and the BNL polarized SRF gun.
FR5PFP071	Thermal Analysis of SCRF Cavity Couplers Using Parallel Multiphysics Tool TEM3P	4473
	V. Akcelik, K. Ko, L. Lee, Z. Li, C.-K. Ng SLAC, Menlo Park, California G. Cheng, R.A. Rimmer, H. Wang JLAB, Newport News, Virginia
	Funding: This work was supported by DOE Contract No. DE-AC02-76SF00515 and used resources of NERSC supported by DOE Contract No. DE-AC02-05CH11231, and of NCCS supported by DOE Contract No. DE-AC05-00OR22725. SLAC has developed a multi-physics simulation code TEM3P for simulating integrated effects of electromagnetic, thermal and structural effects. TEM3P shares the same finite element infrastructure with EM finite elements codes developed at SLAC. This enables simulations within a single framework. Parallel implementation allows large scale computation, and high fidelity and high accuracy simulations can be performed in faster time. In this paper, TEM3P is used to analyze thermal loading in the coupler end-groups of the JLAB SCRF cavity. The results are benchmarked against measurements.