IPAC2014 - List of Authors (Raubenheimer, T.O.)

Paper	Title	Page
MOPME040	MadFLUKA Beam Line 3D Builder. Simulation of Beam Loss Propagation in Accelerators	463
	M. Santana-Leitner, Y. Nosochkov, T.O. Raubenheimer SLAC, Menlo Park, California, USA
	Funding: This work was supported by Department of Energy contract DE-AC02-76-SFO0515 Beam tracking programs provide information of orbits along the nominal trajectory to design beam-line optics. Other aspects like machine or radiation protection, which inspect the transverse dimensions and volumes, are simulated with radiation transport Monte Carlo codes, some of which also include magnetic tracking capabilities. Evaluation of certain aspects, like beam loss shower induced propagation along a beam line, or beam mis-steering phase-space, would require to combine features of both types of codes, or use the latter ones with full accelerator 3D implementations, often too cumbersome and time consuming. This paper presents MadFLUKA, a program that produces FLUKA compatible geometries from MAD files. Objects selected from a user user-configurable database are auto-replicated with the rules of ‘twiss’ and ‘survey’ files to create beam lines with hundreds of components. FLUKA magnetic subroutine is generated from MAD optics, including history randomization of fields for ray-trace analysis of mis-steering failures. MadFLUKA is used in the design of the LCLS-II, at SLAC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME040
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WEPRO015	RF Injector Beam Dynamics Optimization for LCLS-II	1974
	C. F. Papadopoulos, D. Filippetto, F. Sannibale LBNL, Berkeley, California, USA P. Emma, T.O. Raubenheimer, J.F. Schmerge, L. Wang, F. Zhou SLAC, Menlo Park, California, USA
	Funding: This work was supported in part by the Work supported, in part, by the LCLS-II Project and by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 LCLS-II is a proposal for a high repetition rate (>1 MHz) FEL, based on a CW, superconducting linac. The LCLS-II injector is being optimized by a collaboration from Cornell University, Fermilab, LBNL, and SLAC. There are a number of different possible technical choices for the injector including an rf gun or a high voltage DC gun. In this paper we present the status of the simulations for the injector optimization for an rf gun choice for LCLS-II. A multiobjective genetic optimizer is implemented for this reason, and optimized solutions for different bunch charges, corresponding to different operating modes, are presented. These operating points are also the initial part of the start-to-end simulations for LCLS-II. Finally, we discuss the trade-offs between compression and brightness conservation in the low energy (<100 MeV) part of the accelerator, as well as the status of sensitivity studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO015
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WEPRI067	Multi-Physics Analysis of CW Superconducting Cavity for the LCLS-II using ACE3P	2645
	Z. Li, C. Adolphsen, O. Kononenko, T.O. Raubenheimer, C.H. Rivetta, M.C. Ross, L. Xiao SLAC, Menlo Park, California, USA
	Funding: Work was supported by the U.S. DOE contract DE-AC02-76SF00515 and used the resources of NERSC at LBNL under US DOE Contract No. DE-AC03-76SF00098. The LCLS-II linac utilizes superconducting technology operating at continuous wave to accelerate the 1-MHz electron beams to 4 GeV to produce tunable FELs. The TESLA 9-cell superconducting cavity is adopted as the baseline design for the linac. The design gradient is approximately 16 MV/m. The highest operating current is 300 μA. Assuming that the RF power is matched at the highest current, the optimal loaded QL of the cavity is found to be around 4·10⁷. Because of the high QL, the cavity bandwidth approaches the background microphonic detuning, and the performance of the cavity is tightly coupled to the mechanical perturbations of the cavity/cryomodule system. The resulting large phase and amplitude variations in the cavity require active feedback to achieve the 0.01% amplitude and phase stability requirements. To understand the cavity RF response and feedback requirements to the microphonics and Lorentz Force detuning, we have developed a simulation model of the RF-mechanical coupled system using parameters obtained with the multi-physics solver ACE3P. We will present the simulation results of the LCLS-II linac under different power feed scenarios and feedback schemes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI067
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THPRO034	Design of the LCLS-II Electron Optics	2940
	Y. Nosochkov, P. Emma, T.O. Raubenheimer, M. Woodley SLAC, Menlo Park, California, USA
	Funding: Work supported by the US Department of Energy Contract DE-AC02-76SF00515. The LCLS-II project is a high repetition rate, high average brightness free-electron laser based on the existing facilities at the SLAC National Accelerator Laboratory. The LCLS-II will be driven by a new CW superconducting RF (SCRF) 4-GeV linac replacing the existing Cu-linac in the 1st km of the linac tunnel. The SCRF linac will include chicanes for providing full compression of the electron bunch length. After the linac, the electron beam will be directed into the existing 2-km bypass line connecting to the Beam Switch Yard (BSY), where a new spreader system will allow a high rate bunch-by-bunch deflection into the hard X-ray (HXR) or soft X-ray (SXR) transport lines, or towards the BSY high power dump. The HXR line will include a new variable gap undulator replacing the existing LCLS-I undulator and will reuse the existing LCLS-I linac-to-undulator and dump transport lines. The SXR will require a new transport line sharing the same tunnel with the HXR and will include a new variable gap undulator. Overview of the electron beam transport and the optics design are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO034
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THPRI013	A Beam Driven Plasma-wakefield Linear Collider from Higgs Factory to Multi-TeV	3791
	J.-P. Delahaye, E. Adli, S.J. Gessner, M.J. Hogan, T.O. Raubenheimer SLAC, Menlo Park, California, USA W. An, C. Joshi, W.B. Mori UCLA, Los Angeles, California, USA
	An updated design of a beam-driven Plasma Wake-Field Acceleration Linear Collider (PWFA-LC) covering a wide range of beam collision energy from Higgs factory to multi-TeV is presented. The large effective accelerating field on the order of 1 GV/m and high wall-plug to beam power transfer efficiency of the beam driven plasma technology in a continuous operation mode allows to extend linear colliders to unprecedented beam collision energies up to 10 TeV with reasonable facility extension and power consumption. An attractive scheme of an ILC energy upgrade using the PWFA technology in a pulsed mode is discussed. The major critical issues and the R&D to address their feasibility in dedicated test facilities like FACET and FACET2 are outlined, especially the beam quality preservation during acceleration and the positron acceleration. Finally, a tentative scenario of a series of staged facilities with increasing complexity starting with short term application at low energy is developed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI013
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Paper

Title

Page

MadFLUKA Beam Line 3D Builder. Simulation of Beam Loss Propagation in Accelerators

463

M. Santana-Leitner, Y. Nosochkov, T.O. Raubenheimer
SLAC, Menlo Park, California, USA

Funding: This work was supported by Department of Energy contract DE-AC02-76-SFO0515
Beam tracking programs provide information of orbits along the nominal trajectory to design beam-line optics. Other aspects like machine or radiation protection, which inspect the transverse dimensions and volumes, are simulated with radiation transport Monte Carlo codes, some of which also include magnetic tracking capabilities. Evaluation of certain aspects, like beam loss shower induced propagation along a beam line, or beam mis-steering phase-space, would require to combine features of both types of codes, or use the latter ones with full accelerator 3D implementations, often too cumbersome and time consuming. This paper presents MadFLUKA, a program that produces FLUKA compatible geometries from MAD files. Objects selected from a user user-configurable database are auto-replicated with the rules of ‘twiss’ and ‘survey’ files to create beam lines with hundreds of components. FLUKA magnetic subroutine is generated from MAD optics, including history randomization of fields for ray-trace analysis of mis-steering failures. MadFLUKA is used in the design of the LCLS-II, at SLAC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO015

RF Injector Beam Dynamics Optimization for LCLS-II

1974

C. F. Papadopoulos, D. Filippetto, F. Sannibale
LBNL, Berkeley, California, USA
P. Emma, T.O. Raubenheimer, J.F. Schmerge, L. Wang, F. Zhou
SLAC, Menlo Park, California, USA

Funding: This work was supported in part by the Work supported, in part, by the LCLS-II Project and by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
LCLS-II is a proposal for a high repetition rate (>1 MHz) FEL, based on a CW, superconducting linac. The LCLS-II injector is being optimized by a collaboration from Cornell University, Fermilab, LBNL, and SLAC. There are a number of different possible technical choices for the injector including an rf gun or a high voltage DC gun. In this paper we present the status of the simulations for the injector optimization for an rf gun choice for LCLS-II. A multiobjective genetic optimizer is implemented for this reason, and optimized solutions for different bunch charges, corresponding to different operating modes, are presented. These operating points are also the initial part of the start-to-end simulations for LCLS-II. Finally, we discuss the trade-offs between compression and brightness conservation in the low energy (<100 MeV) part of the accelerator, as well as the status of sensitivity studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI067

Multi-Physics Analysis of CW Superconducting Cavity for the LCLS-II using ACE3P

2645

Z. Li, C. Adolphsen, O. Kononenko, T.O. Raubenheimer, C.H. Rivetta, M.C. Ross, L. Xiao
SLAC, Menlo Park, California, USA

Funding: Work was supported by the U.S. DOE contract DE-AC02-76SF00515 and used the resources of NERSC at LBNL under US DOE Contract No. DE-AC03-76SF00098.
The LCLS-II linac utilizes superconducting technology operating at continuous wave to accelerate the 1-MHz electron beams to 4 GeV to produce tunable FELs. The TESLA 9-cell superconducting cavity is adopted as the baseline design for the linac. The design gradient is approximately 16 MV/m. The highest operating current is 300 μA. Assuming that the RF power is matched at the highest current, the optimal loaded QL of the cavity is found to be around 4·10⁷. Because of the high QL, the cavity bandwidth approaches the background microphonic detuning, and the performance of the cavity is tightly coupled to the mechanical perturbations of the cavity/cryomodule system. The resulting large phase and amplitude variations in the cavity require active feedback to achieve the 0.01% amplitude and phase stability requirements. To understand the cavity RF response and feedback requirements to the microphonics and Lorentz Force detuning, we have developed a simulation model of the RF-mechanical coupled system using parameters obtained with the multi-physics solver ACE3P. We will present the simulation results of the LCLS-II linac under different power feed scenarios and feedback schemes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI067

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO034

Design of the LCLS-II Electron Optics

2940

Y. Nosochkov, P. Emma, T.O. Raubenheimer, M. Woodley
SLAC, Menlo Park, California, USA

Funding: Work supported by the US Department of Energy Contract DE-AC02-76SF00515.
The LCLS-II project is a high repetition rate, high average brightness free-electron laser based on the existing facilities at the SLAC National Accelerator Laboratory. The LCLS-II will be driven by a new CW superconducting RF (SCRF) 4-GeV linac replacing the existing Cu-linac in the 1st km of the linac tunnel. The SCRF linac will include chicanes for providing full compression of the electron bunch length. After the linac, the electron beam will be directed into the existing 2-km bypass line connecting to the Beam Switch Yard (BSY), where a new spreader system will allow a high rate bunch-by-bunch deflection into the hard X-ray (HXR) or soft X-ray (SXR) transport lines, or towards the BSY high power dump. The HXR line will include a new variable gap undulator replacing the existing LCLS-I undulator and will reuse the existing LCLS-I linac-to-undulator and dump transport lines. The SXR will require a new transport line sharing the same tunnel with the HXR and will include a new variable gap undulator. Overview of the electron beam transport and the optics design are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI013

A Beam Driven Plasma-wakefield Linear Collider from Higgs Factory to Multi-TeV

3791

J.-P. Delahaye, E. Adli, S.J. Gessner, M.J. Hogan, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
W. An, C. Joshi, W.B. Mori
UCLA, Los Angeles, California, USA

An updated design of a beam-driven Plasma Wake-Field Acceleration Linear Collider (PWFA-LC) covering a wide range of beam collision energy from Higgs factory to multi-TeV is presented. The large effective accelerating field on the order of 1 GV/m and high wall-plug to beam power transfer efficiency of the beam driven plasma technology in a continuous operation mode allows to extend linear colliders to unprecedented beam collision energies up to 10 TeV with reasonable facility extension and power consumption. An attractive scheme of an ILC energy upgrade using the PWFA technology in a pulsed mode is discussed. The major critical issues and the R&D to address their feasibility in dedicated test facilities like FACET and FACET2 are outlined, especially the beam quality preservation during acceleration and the positron acceleration. Finally, a tentative scenario of a series of staged facilities with increasing complexity starting with short term application at low energy is developed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)