IPAC2014 - List of Authors (Berg, J.S.)

Paper	Title	Page
TUPRO115	Progress on the Dipole Magnet for a Rapid Cycling Synchrotron	1322
	H. Witte, J.S. Berg BNL, Upton, Long Island, New York, USA M.L. Lopes Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. A rapid cycling hybrid synchrotron has been proposed for the acceleration of muons from 375 to 750 GeV. The bending in a hybrid synchrotron is created with interleaved cold and warm dipoles; the warm dipoles modulate the average bending field for the different particle momenta. A key challenge for the warm dipole magnets is the ramp rate, which is equivalent to frequencies of 400-1000 Hz. Recently a design has been suggested which employs 6.5 Si steel for the return yoke and FeCo for the poles. In simulations the design has shown a good performance (up to 2T) due to the FeCo and acceptable power losses by employing SiFe with a high Si content. The paper discusses the effect of eddy currents induced in the laminations and hysteresis effects on the field quality.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO115
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TUPME019	Design and Simulation of a High Field - low energy Muon Ionization Cooling Channel	1386
	H. K. Sayed, J.S. Berg, R.B. Palmer, D. Stratakis BNL, Upton, Long Island, New York, USA
	Muon beams are generated with inherited large transverse and longitudinal emittances. In order to achieve low emittance within the short lifetime of the muons, the only feasible cooling scheme is the ionization cooling. In this study we present a design and simulation of a novel ionization cooling channel. The channel operates at a very strong magnetic fields of 25-30 T with low muon beam energy starting from 66 MeV and decreasing gradually. We study the beam dynamics of such low energy beam in high field region inside and between cooling stages. Key design parameters will be presented and in addition the performance and channel requirements of RF cavities and high field magnets will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME019
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TUPME020	Complete Six-dimensional Muon Cooling Channel for a Muon Collider	1389
	D. Stratakis, J.S. Berg, R.B. Palmer, H. Witte BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. We describe a complete 6D rectilinear cooling scheme for use in a Muon Collider. This scheme uses separate 6D cooling channels for the two signs of particle charge. In each, a channel first reduces the emittance of a train of 21 muon bunches until it becomes possible to merge them into a single bunch, one of each sign. The single bunches are then sent through a second rectilinear channel for further cooling towards the requirements of a Muon Collider. We adopt this approach for a new cooling lattice design for the Muon Collider, and for the first time present a end-to-end simulation. We review key parameters such as the required focusing fields, absorber lengths, cavity frequencies and rf gradients. *D. Stratakis et al., Phys. Rev. ST AB 16, 091001 (2013).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME020
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TUPME022	Design and Optimization of a Particle Selection System for Muon based Accelerators	1395
	D. Stratakis, J.S. Berg BNL, Upton, Long Island, New York, USA D.V. Neuffer Fermilab, Batavia, Illinois, USA P. Snopok Illinois Institute of Technology, Chicago, Illinois, USA
	Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In Muon Accelerators muons are produced by impacting high energy protons onto a target to produce pions. The pions decay to muons which are then accelerated. Through this process a significant background of protons and electrons are generated, which may result in heat deposition on superconducting materials and activation of the machine. In this paper we propose a two-step particle selection scheme: a chicane to remove the high momentum particles from the beam and a Beryllium block absorber that reduces momentum of all particles in the beam, resulting in the loss of low momentum protons. We review the design and numerically examine its impact on the performance of the muon front-end.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME022
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TUPME023	Overview of a muon capture section for muon accelerators	1398
	D. Stratakis, J.S. Berg, H. K. Sayed BNL, Upton, Long Island, New York, USA D.V. Neuffer, P. Snopok Fermilab, Batavia, Illinois, USA P. Snopok Illinois Institute of Technology, Chicago, Illinois, USA
	Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. We describe a muon capture section to manipulate the longitudinal and transverse phase-space so that to collect efficiently a muon beam produced from an intense proton source target. We show that this can be achieved by using a set of properly tuned rf cavities that captures the beam into string of bunches and aligns them into nearly equal central energies, and a solenoidal chicane that filters high momentum particles, followed by a proton absorber that reduces the energy of all particles. This work elucidates the key parameters that are needed for successful muon capture, such as the required rf frequencies, rf gradients and focusing field. We discuss the sensitivity in performance against the number of different rf frequencies and accelerating rf gradient.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME023
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WEPRI103	Magnet Design for a Six-dimensional Rectilinear Cooling Channel - Feasibility Study	2740
	H. Witte, J.S. Berg, R.B. Palmer, D. Stratakis BNL, Upton, Long Island, New York, USA F. Borgnolutti LBNL, Berkeley, California, USA
	Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. An essential part of a potential future muon collider is ionization cooling, which is required to reduce the emittance of the muon beam. A new scheme has recently been proposed which in simulations shows an improved performance in terms of cooling efficiency and transmitted muons. The lattice of this cooling channel consists of 12 stages, each of which requires different superconducting solenoids. The most challenging stage is the last one, where the solenoids are expected to deliver 15.1T in a bore of ~4.5 cm. This paper discusses the feasibility of the solenoids for the last stage of this lattice.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI103
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Paper

Title

Page

Progress on the Dipole Magnet for a Rapid Cycling Synchrotron

1322

H. Witte, J.S. Berg
BNL, Upton, Long Island, New York, USA
M.L. Lopes
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A rapid cycling hybrid synchrotron has been proposed for the acceleration of muons from 375 to 750 GeV. The bending in a hybrid synchrotron is created with interleaved cold and warm dipoles; the warm dipoles modulate the average bending field for the different particle momenta. A key challenge for the warm dipole magnets is the ramp rate, which is equivalent to frequencies of 400-1000 Hz. Recently a design has been suggested which employs 6.5 Si steel for the return yoke and FeCo for the poles. In simulations the design has shown a good performance (up to 2T) due to the FeCo and acceptable power losses by employing SiFe with a high Si content. The paper discusses the effect of eddy currents induced in the laminations and hysteresis effects on the field quality.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO115

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

TUPME019

Design and Simulation of a High Field - low energy Muon Ionization Cooling Channel

1386

H. K. Sayed, J.S. Berg, R.B. Palmer, D. Stratakis
BNL, Upton, Long Island, New York, USA

Muon beams are generated with inherited large transverse and longitudinal emittances. In order to achieve low emittance within the short lifetime of the muons, the only feasible cooling scheme is the ionization cooling. In this study we present a design and simulation of a novel ionization cooling channel. The channel operates at a very strong magnetic fields of 25-30 T with low muon beam energy starting from 66 MeV and decreasing gradually. We study the beam dynamics of such low energy beam in high field region inside and between cooling stages. Key design parameters will be presented and in addition the performance and channel requirements of RF cavities and high field magnets will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME019

Export •

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

TUPME020

Complete Six-dimensional Muon Cooling Channel for a Muon Collider

1389

D. Stratakis, J.S. Berg, R.B. Palmer, H. Witte
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
We describe a complete 6D rectilinear cooling scheme for use in a Muon Collider. This scheme uses separate 6D cooling channels for the two signs of particle charge. In each, a channel first reduces the emittance of a train of 21 muon bunches until it becomes possible to merge them into a single bunch, one of each sign. The single bunches are then sent through a second rectilinear channel for further cooling towards the requirements of a Muon Collider. We adopt this approach for a new cooling lattice design for the Muon Collider, and for the first time present a end-to-end simulation. We review key parameters such as the required focusing fields, absorber lengths, cavity frequencies and rf gradients.
*D. Stratakis et al., Phys. Rev. ST AB 16, 091001 (2013).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME020

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

TUPME022

Design and Optimization of a Particle Selection System for Muon based Accelerators

1395

D. Stratakis, J.S. Berg
BNL, Upton, Long Island, New York, USA
D.V. Neuffer
Fermilab, Batavia, Illinois, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In Muon Accelerators muons are produced by impacting high energy protons onto a target to produce pions. The pions decay to muons which are then accelerated. Through this process a significant background of protons and electrons are generated, which may result in heat deposition on superconducting materials and activation of the machine. In this paper we propose a two-step particle selection scheme: a chicane to remove the high momentum particles from the beam and a Beryllium block absorber that reduces momentum of all particles in the beam, resulting in the loss of low momentum protons. We review the design and numerically examine its impact on the performance of the muon front-end.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME022

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

TUPME023

Overview of a muon capture section for muon accelerators

1398

D. Stratakis, J.S. Berg, H. K. Sayed
BNL, Upton, Long Island, New York, USA
D.V. Neuffer, P. Snopok
Fermilab, Batavia, Illinois, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
We describe a muon capture section to manipulate the longitudinal and transverse phase-space so that to collect efficiently a muon beam produced from an intense proton source target. We show that this can be achieved by using a set of properly tuned rf cavities that captures the beam into string of bunches and aligns them into nearly equal central energies, and a solenoidal chicane that filters high momentum particles, followed by a proton absorber that reduces the energy of all particles. This work elucidates the key parameters that are needed for successful muon capture, such as the required rf frequencies, rf gradients and focusing field. We discuss the sensitivity in performance against the number of different rf frequencies and accelerating rf gradient.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME023

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

WEPRI103

Magnet Design for a Six-dimensional Rectilinear Cooling Channel - Feasibility Study

2740

H. Witte, J.S. Berg, R.B. Palmer, D. Stratakis
BNL, Upton, Long Island, New York, USA
F. Borgnolutti
LBNL, Berkeley, California, USA

Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
An essential part of a potential future muon collider is ionization cooling, which is required to reduce the emittance of the muon beam. A new scheme has recently been proposed which in simulations shows an improved performance in terms of cooling efficiency and transmitted muons. The lattice of this cooling channel consists of 12 stages, each of which requires different superconducting solenoids. The most challenging stage is the last one, where the solenoids are expected to deliver 15.1T in a bore of ~4.5 cm. This paper discusses the feasibility of the solenoids for the last stage of this lattice.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI103

Export •

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