IPAC2012 - List of Authors (Krafft, G.A.)

Paper	Title	Page
MOPPC045	Scaled Electron Model of a Dogbone Muon RLA with Multi-pass Arcs	235
	S.A. Bogacz, A. Hutton, G.A. Krafft, V.S. Morozov, Y. Roblin JLAB, Newport News, Virginia, USA K.B. Beard, R.P. Johnson Muons, Inc, Batavia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by USDOE STTR Grant DE-FG02-08ER86351. The design of a dogbone RLA with linear-field multi-pass arcs was earlier developed for accelerating muons for a future Neutrino Factory and Muon Collider. It allows for efficient use of expensive RF while the multi-pass arc design based on linear combined-function magnets exhibits a number of advantages over single pass or pulsed arc designs. Such an RLA may have applications going beyond muon acceleration. This paper describes a possible straightforward test of this concept by scaling a GeV scale muon design for electrons. Scaling muon momenta by the muon-to-electron mass ratio leads to a scheme in which a 4.35 MeV/c electron beam is injected in the middle of a 2.9 MeV/pass linac with two double-pass return arcs, and is accelerated to 17.4 MeV/c in 4.5 passes. All spatial dimensions including the orbit distortion are scaled by a factor of 7.5, which arises from scaling the 200 MHz muon RF to a readily available 1.5 GHz. The footprint of a complete RLA fits in an area of 25 by 7 m. The scheme utilizes only fixed magnetic fields including injection and extraction. The hardware requirements are not very demanding, making it feasible to utilize the existing technologies. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

MOPPD016	Status of Proof-of-principle Experiment for Coherent Electron Cooling	400
	I. Pinayev, S.A. Belomestnykh, I. Ben-Zvi, J. Bengtsson, A. Elizarov, A.V. Fedotov, D.M. Gassner, Y. Hao, D. Kayran, V. Litvinenko, G.J. Mahler, W. Meng, T. Roser, B. Sheehy, R. Than, J.E. Tuozzolo, G. Wang, S.D. Webb, V. Yakimenko BNL, Upton, Long Island, New York, USA G.I. Bell, D.L. Bruhwiler, V.H. Ranjbar, B.T. Schwartz Tech-X, Boulder, Colorado, USA A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer JLAB, Newport News, Virginia, USA M.A. Kholopov, P. Vobly BINP SB RAS, Novosibirsk, Russia
	Funding: US DOE Office of Science, DE-FC02-07ER41499, DE-FG02-08ER85182; NERSC DOE contract No. DE-AC02-05CH11231. Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o’clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters.

TUPPC097	Computational Modeling of Electron Cloud For MEIC	1383
	S. Ahmed, J.D. Dolph, G.A. Krafft, T. Satogata, B.C. Yunn JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. This work is the continuation of our earlier studies on electron cloud (EC) simulations reported in IPAC'11 for the medium energy electron-ion collider (MEIC) envisioned at JLab beyond the 12 GeV upgrade of CEBAF. In this paper, we will study the EC saturation density in various MEIC operations scenarios to calculate details of the EC-induced wakefield to establish more stringent bounds on instability thresholds and determine whether EC mitigation, such as NEG coatings or solenoid fields, should be considered in the MEIC design.

TUPPR082	MEIC Design Progress	2014
	Y. Zhang, Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, R. Li, F. Lin, V.S. Morozov, E.W. Nissen, F.C. Pilat, T. Satogata, C. Tennant, B. Terzić, B.C. Yunn JLAB, Newport News, Virginia, USA D.P. Barber DESY, Hamburg, Germany Y. Filatov JINR, Dubna, Russia C. Hyde Old Dominion University, Norfolk, Virginia, USA A.M. Kondratenko Science and Technique Laboratory Zaryad, Novosibirsk, Russia S.L. Manikonda, P.N. Ostroumov ANL, Argonne, USA M.K. Sullivan SLAC, Menlo Park, California, USA
	Funding: Supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and No. DE-AC02-06CH11357. This paper will report the recent progress in the conceptual design of MEIC, a high luminosity medium energy polarized ring-ring electron-ion collider at Jefferson lab. The topics and achievements that will be covered are design of the ion large booster and the ERL-circulator-ring-based electron cooling facility, optimization of chromatic corrections and dynamic aperture studies, schemes and tracking simulations of lepton and ion polarization in the figure-8 collider ring, and the beam-beam and electron cooling simulations. A proposal of a test facility for the MEIC electron cooler will also be discussed.

WEPPR093	Impedance Budget for Crab Cavity in MEIC Electron Ring	3153
	S. Ahmed, G.A. Krafft, B.C. Yunn JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The Medium Energy Electron-Ion Collider (MEIC) at Jefferson Lab has been envisioned as a first stage high energy particle accelerator beyond the 12 GeV upgrade of CEBAF. The estimate of impedance budget is important from the view point of beam stability and matching with other accelerator components driving currents. The detailed study of impedance budget for electron ring has been performed by considering the current design parameters of the e-ring. A comprehensive picture of the calculations involved in this study has been illustrated in the paper.

THPPR030	High Power Test of RF Separator For 12 GeV Upgrade of CEBAF at Jefferson Lab	4032
	S. Ahmed, C. Hovater, G.A. Krafft, J.D. Mammosser, M. Spata, M.J. Wissmann JLAB, Newport News, Virginia, USA J.R. Delayen ODU, Norfolk, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. CEBAF at JLab is in the process of an energy upgrade from 6 GeV to 12 GeV. The existing setup of the RF separator cavities in the 5th pass will not be adequate enough to extract the highest energy (11 GeV) beam to any two existing halls (A, B or C) while simultaneously delivering to the new hall D in the case of the proposed 12 GeV upgrade of the machine. To restore this capability, several options including the extension of existing normal conducting (NC) and a potential 499 MHz TEM-type superconducting (SC) cavity design have been investigated using computer simulations. Detailed numerical studies suggest that six 2-cell normal conducting structures meet the requirements; each 2-cell structure will require up to 4 kW RF input power in contrast with the current nominal operating power of 1.0 to 2.0 kW. A high power test to 4 kW is required to confirm the cavity’s operate-ability at these elevated gradient and power levels. We have assembled a 2-cell cavity, pumped down to 2.0·10^-9 torr using ion pump and confirmed the low level RF performance. A high power test is in progress and will be completed soon. The detailed numerical and experimental results will be discussed in the paper.

WEPPC100	Design of Electron and Ion Crabbing Cavities for an Electron-Ion Collider	2447
	A. Castilla, J.R. Delayen, G.A. Krafft ODU, Norfolk, Virginia, USA A. Castilla JLAB, Newport News, Virginia, USA
	Beyond the 12 GeV upgrade at the Jefferson Lab a Medium Energy Electron-Ion Collider (MEIC) has been considered. In order to achieve the desired high luminosities at the Interaction Points (IP), the use of crabbing cavities is under study. In this work, we will present to-date designs of superconducting cavities, considered for crabbing both ion and electron bunches. A discussion of properties such as peak surface fields and higher-order mode separation will be presented.

Paper

Title

Page

Scaled Electron Model of a Dogbone Muon RLA with Multi-pass Arcs

235

S.A. Bogacz, A. Hutton, G.A. Krafft, V.S. Morozov, Y. Roblin
JLAB, Newport News, Virginia, USA
K.B. Beard, R.P. Johnson
Muons, Inc, Batavia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Supported in part by USDOE STTR Grant DE-FG02-08ER86351.
The design of a dogbone RLA with linear-field multi-pass arcs was earlier developed for accelerating muons for a future Neutrino Factory and Muon Collider. It allows for efficient use of expensive RF while the multi-pass arc design based on linear combined-function magnets exhibits a number of advantages over single pass or pulsed arc designs. Such an RLA may have applications going beyond muon acceleration. This paper describes a possible straightforward test of this concept by scaling a GeV scale muon design for electrons. Scaling muon momenta by the muon-to-electron mass ratio leads to a scheme in which a 4.35 MeV/c electron beam is injected in the middle of a 2.9 MeV/pass linac with two double-pass return arcs, and is accelerated to 17.4 MeV/c in 4.5 passes. All spatial dimensions including the orbit distortion are scaled by a factor of 7.5, which arises from scaling the 200 MHz muon RF to a readily available 1.5 GHz. The footprint of a complete RLA fits in an area of 25 by 7 m. The scheme utilizes only fixed magnetic fields including injection and extraction. The hardware requirements are not very demanding, making it feasible to utilize the existing technologies.
The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

MOPPD016

Status of Proof-of-principle Experiment for Coherent Electron Cooling

400

I. Pinayev, S.A. Belomestnykh, I. Ben-Zvi, J. Bengtsson, A. Elizarov, A.V. Fedotov, D.M. Gassner, Y. Hao, D. Kayran, V. Litvinenko, G.J. Mahler, W. Meng, T. Roser, B. Sheehy, R. Than, J.E. Tuozzolo, G. Wang, S.D. Webb, V. Yakimenko
BNL, Upton, Long Island, New York, USA
G.I. Bell, D.L. Bruhwiler, V.H. Ranjbar, B.T. Schwartz
Tech-X, Boulder, Colorado, USA
A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer
JLAB, Newport News, Virginia, USA
M.A. Kholopov, P. Vobly
BINP SB RAS, Novosibirsk, Russia

Funding: US DOE Office of Science, DE-FC02-07ER41499, DE-FG02-08ER85182; NERSC DOE contract No. DE-AC02-05CH11231.
Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o’clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters.

TUPPC097

Computational Modeling of Electron Cloud For MEIC

1383

S. Ahmed, J.D. Dolph, G.A. Krafft, T. Satogata, B.C. Yunn
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
This work is the continuation of our earlier studies on electron cloud (EC) simulations reported in IPAC'11 for the medium energy electron-ion collider (MEIC) envisioned at JLab beyond the 12 GeV upgrade of CEBAF. In this paper, we will study the EC saturation density in various MEIC operations scenarios to calculate details of the EC-induced wakefield to establish more stringent bounds on instability thresholds and determine whether EC mitigation, such as NEG coatings or solenoid fields, should be considered in the MEIC design.

TUPPR082

MEIC Design Progress

2014

Y. Zhang, Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, R. Li, F. Lin, V.S. Morozov, E.W. Nissen, F.C. Pilat, T. Satogata, C. Tennant, B. Terzić, B.C. Yunn
JLAB, Newport News, Virginia, USA
D.P. Barber
DESY, Hamburg, Germany
Y. Filatov
JINR, Dubna, Russia
C. Hyde
Old Dominion University, Norfolk, Virginia, USA
A.M. Kondratenko
Science and Technique Laboratory Zaryad, Novosibirsk, Russia
S.L. Manikonda, P.N. Ostroumov
ANL, Argonne, USA
M.K. Sullivan
SLAC, Menlo Park, California, USA

Funding: Supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and No. DE-AC02-06CH11357.
This paper will report the recent progress in the conceptual design of MEIC, a high luminosity medium energy polarized ring-ring electron-ion collider at Jefferson lab. The topics and achievements that will be covered are design of the ion large booster and the ERL-circulator-ring-based electron cooling facility, optimization of chromatic corrections and dynamic aperture studies, schemes and tracking simulations of lepton and ion polarization in the figure-8 collider ring, and the beam-beam and electron cooling simulations. A proposal of a test facility for the MEIC electron cooler will also be discussed.

WEPPR093

Impedance Budget for Crab Cavity in MEIC Electron Ring

3153

S. Ahmed, G.A. Krafft, B.C. Yunn
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The Medium Energy Electron-Ion Collider (MEIC) at Jefferson Lab has been envisioned as a first stage high energy particle accelerator beyond the 12 GeV upgrade of CEBAF. The estimate of impedance budget is important from the view point of beam stability and matching with other accelerator components driving currents. The detailed study of impedance budget for electron ring has been performed by considering the current design parameters of the e-ring. A comprehensive picture of the calculations involved in this study has been illustrated in the paper.

THPPR030

High Power Test of RF Separator For 12 GeV Upgrade of CEBAF at Jefferson Lab

4032

S. Ahmed, C. Hovater, G.A. Krafft, J.D. Mammosser, M. Spata, M.J. Wissmann
JLAB, Newport News, Virginia, USA
J.R. Delayen
ODU, Norfolk, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
CEBAF at JLab is in the process of an energy upgrade from 6 GeV to 12 GeV. The existing setup of the RF separator cavities in the 5th pass will not be adequate enough to extract the highest energy (11 GeV) beam to any two existing halls (A, B or C) while simultaneously delivering to the new hall D in the case of the proposed 12 GeV upgrade of the machine. To restore this capability, several options including the extension of existing normal conducting (NC) and a potential 499 MHz TEM-type superconducting (SC) cavity design have been investigated using computer simulations. Detailed numerical studies suggest that six 2-cell normal conducting structures meet the requirements; each 2-cell structure will require up to 4 kW RF input power in contrast with the current nominal operating power of 1.0 to 2.0 kW. A high power test to 4 kW is required to confirm the cavity’s operate-ability at these elevated gradient and power levels. We have assembled a 2-cell cavity, pumped down to 2.0·10^-9 torr using ion pump and confirmed the low level RF performance. A high power test is in progress and will be completed soon. The detailed numerical and experimental results will be discussed in the paper.

WEPPC100

Design of Electron and Ion Crabbing Cavities for an Electron-Ion Collider

2447

A. Castilla, J.R. Delayen, G.A. Krafft
ODU, Norfolk, Virginia, USA
A. Castilla
JLAB, Newport News, Virginia, USA

Beyond the 12 GeV upgrade at the Jefferson Lab a Medium Energy Electron-Ion Collider (MEIC) has been considered. In order to achieve the desired high luminosities at the Interaction Points (IP), the use of crabbing cavities is under study. In this work, we will present to-date designs of superconducting cavities, considered for crabbing both ion and electron bunches. A discussion of properties such as peak surface fields and higher-order mode separation will be presented.