IPAC2013 - List of Authors (Ryne, R.D.)

Paper	Title	Page
MOPWO062	A Parallel Multi-objective Differential Evolution Algorithm for Photoinjector Beam Dynamics Optimization	1031
	J. Qiang, C.E. Mitchell, S. Paret, R.D. Ryne LBNL, Berkeley, California, USA Y.X. Chao UCB, Berkeley, California, USA
	Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 In photoinjector design, there is growing interest in using multi-objective beam dynamics optimization to minimize the final transverse emittances and to maximize the final peak current of the beam. Most previous studies in this area were based on genetic algorithms. Recent progress in optimization suggests that the differential evolution algorithm could perform better in comparison to the genetic algorithm. In this paper, we propose a new parallel multi-objective optimizer based on the differential evolution algorithm for photoinjector beam dynamics optimization. We will discuss the numerical algorithm and some benchmark examples. This algorithm has the potential to significantly reduce the computation time required to reach the optimal Pareto solution.

TUPFI057	Muon Accelerators for the Next Generation of High Energy Physics Experiments	1475
	M.A. Palmer, S. Brice, A.D. Bross, D.S. Denisov, E. Eichten, R.J. Lipton, D.V. Neuffer Fermilab, Batavia, USA C.M. Ankenbrandt Muons. Inc., USA S.A. Bogacz JLAB, Newport News, Virginia, USA J.-P. Delahaye SLAC, Menlo Park, California, USA P. Huber Virginia Polytechnic Institute and State University, Blacksburg, USA D.M. Kaplan, P. Snopok Illinois Institute of Technology, Chicago, Illinois, USA H.G. Kirk, R.B. Palmer BNL, Upton, Long Island, New York, USA R.D. Ryne LBNL, Berkeley, California, USA
	Funding: Work supported by the U.S. Department of Energy and the U.S. National Science Foundation Muon accelerator technology offers a unique and very promising avenue to a facility capable of producing high intensity muon beams for neutrino factory and multi-TeV lepton collider applications. The goal of the US Muon Accelerator Program is to provide an assessment, within the next 6 years, of the physics potential and technical feasibility of such a facility. This talk will describe the physics opportunities that are envisioned, along with the R&D efforts that are being undertaken to address key accelerator physics and technology questions.

TUPFI058	Simulation of Beam-induced Gas Plasma in High Gradient RF Field for Muon Colliders	1478
	K. Yonehara, M. Chung, A.V. Tollestrup Fermilab, Batavia, USA B.T. Freemire IIT, Chicago, Illinois, USA R.P. Johnson, T.J. Roberts Muons. Inc., USA R.D. Ryne LBNL, Berkeley, California, USA V. Samulyak BNL, Upton, Long Island, New York, USA K. Yu SBU, Stony Brook, USA
	There is a strong limit of available RF gradient in a vacuum RF cavity under magnetic fields because the magnetic field enhances a dark current density due to electron focusing and increases probability of an electric breakdown. This limits the cooling performance. A dense hydrogen gas filled RF cavity can break this limit because the gas acts as a buffer of dark current. However, RF power loading due to a beam-induced plasma in a dense gas filled RF cavity (plasma loading effect) is crucial to design the practical cavity. Experiment shows that the plasma loading can be mitigated in denser hydrogen gas and by doping a small amount of electronegative gas in the cavity. A complicate plasma chemical reaction should be dominated in such a dense hydrogen gas condition. A beam-induced plasma is simulated by taking into account the plasma chemistry to reproduce the condition by using the supercomputer at LBNL. We will also investigate the space charge effect in a dense gas in this effort.

Paper

Title

Page

A Parallel Multi-objective Differential Evolution Algorithm for Photoinjector Beam Dynamics Optimization

1031

J. Qiang, C.E. Mitchell, S. Paret, R.D. Ryne
LBNL, Berkeley, California, USA
Y.X. Chao
UCB, Berkeley, California, USA

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
In photoinjector design, there is growing interest in using multi-objective beam dynamics optimization to minimize the final transverse emittances and to maximize the final peak current of the beam. Most previous studies in this area were based on genetic algorithms. Recent progress in optimization suggests that the differential evolution algorithm could perform better in comparison to the genetic algorithm. In this paper, we propose a new parallel multi-objective optimizer based on the differential evolution algorithm for photoinjector beam dynamics optimization. We will discuss the numerical algorithm and some benchmark examples. This algorithm has the potential to significantly reduce the computation time required to reach the optimal Pareto solution.

TUPFI057

Muon Accelerators for the Next Generation of High Energy Physics Experiments

1475

M.A. Palmer, S. Brice, A.D. Bross, D.S. Denisov, E. Eichten, R.J. Lipton, D.V. Neuffer
Fermilab, Batavia, USA
C.M. Ankenbrandt
Muons. Inc., USA
S.A. Bogacz
JLAB, Newport News, Virginia, USA
J.-P. Delahaye
SLAC, Menlo Park, California, USA
P. Huber
Virginia Polytechnic Institute and State University, Blacksburg, USA
D.M. Kaplan, P. Snopok
Illinois Institute of Technology, Chicago, Illinois, USA
H.G. Kirk, R.B. Palmer
BNL, Upton, Long Island, New York, USA
R.D. Ryne
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy and the U.S. National Science Foundation
Muon accelerator technology offers a unique and very promising avenue to a facility capable of producing high intensity muon beams for neutrino factory and multi-TeV lepton collider applications. The goal of the US Muon Accelerator Program is to provide an assessment, within the next 6 years, of the physics potential and technical feasibility of such a facility. This talk will describe the physics opportunities that are envisioned, along with the R&D efforts that are being undertaken to address key accelerator physics and technology questions.

TUPFI058

Simulation of Beam-induced Gas Plasma in High Gradient RF Field for Muon Colliders

1478

K. Yonehara, M. Chung, A.V. Tollestrup
Fermilab, Batavia, USA
B.T. Freemire
IIT, Chicago, Illinois, USA
R.P. Johnson, T.J. Roberts
Muons. Inc., USA
R.D. Ryne
LBNL, Berkeley, California, USA
V. Samulyak
BNL, Upton, Long Island, New York, USA
K. Yu
SBU, Stony Brook, USA

There is a strong limit of available RF gradient in a vacuum RF cavity under magnetic fields because the magnetic field enhances a dark current density due to electron focusing and increases probability of an electric breakdown. This limits the cooling performance. A dense hydrogen gas filled RF cavity can break this limit because the gas acts as a buffer of dark current. However, RF power loading due to a beam-induced plasma in a dense gas filled RF cavity (plasma loading effect) is crucial to design the practical cavity. Experiment shows that the plasma loading can be mitigated in denser hydrogen gas and by doping a small amount of electronegative gas in the cavity. A complicate plasma chemical reaction should be dominated in such a dense hydrogen gas condition. A beam-induced plasma is simulated by taking into account the plasma chemistry to reproduce the condition by using the supercomputer at LBNL. We will also investigate the space charge effect in a dense gas in this effort.