IPAC2012 - List of Authors (Neuffer, D.V.)

Paper	Title	Page
MOPPC034	Use of Helical Transport Channels for Bunch Recombination	205
	D.V. Neuffer, K. Yonehara Fermilab, Batavia, USA C.M. Ankenbrandt, C. Y. Yoshikawa Muons, Inc, Batavia, USA
	Cooling scenarios for a high-luminosity Muon Collider require bunch recombination for optimal luminosity. In this paper we describe a new method for bunch recombination. We combine the high-chronicity of a helical transport channel (HTC) with the high-frequency bunching and phase-energy rotation concept (time-reversed) to obtain a compact bunch recombination system adapted to a muon collider scenario. We first present an idealized 1-D system with multiple chronicity transports. We then implement the concept in a single-chronicity channel, obtaining bunch recombination of 13 200MHz-spaced bunches to a single collider-ready bunch within a compact transport with modest rf requirements. That example is demonstrated within G4BL 3-D simulations. Variations and adaptations for different recombination requirements are discussed.

MOPPC041	Control of Beam Losses in the Front End for the Neutrino Factory	223
	C.T. Rogers STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom D.V. Neuffer Fermilab, Batavia, USA P. Snopok IIT, Chicago, Illinois, USA
	The Neutrino Factory produces neutrinos by muon decay in a storage ring. Pions are produced by firing high energy protons onto a target. Pions decay to muons, which are captured and accelerated to high energy. The target produces additionally a large background that is deposited in the muon capture front end and subsequent components. The implications of energy deposition in the front end lattice for the Neutrino Factory are addressed. Several approaches to mitigating the effect are proposed and discussed, including proton absorbers, chicane, and shielding.

MOPPD043	Novel Muon Beam Facilities for Project X at Fermilab	457
	C.M. Ankenbrandt, R.J. Abrams, T.J. Roberts, C. Y. Yoshikawa Muons, Inc, Batavia, USA D.V. Neuffer Fermilab, Batavia, USA
	Innovative muon beam concepts for intensity-frontier experiments such as muon-to-electron conversion are described. Elaborating upon a previous single-beam idea, we have developed a design concept for a system to generate four high quality, low-energy muon beams (two of each sign) from a single beam of protons. As a first step, the production of pions by 1 and 3 GeV protons from the proposed Project X linac at Fermilab is being simulated and compared with the 8-GeV results from the previous study.

MOPPD044	Optimization of the Target Subsystem for the New g-2 Experiment	460
	C. Y. Yoshikawa, C.M. Ankenbrandt Muons, Inc, Batavia, USA A.F. Leveling, N.V. Mokhov, J.P. Morgan, D.V. Neuffer, S.I. Striganov Fermilab, Batavia, USA
	A precision measurement of the muon anomalous magnetic moment, aμ = (g-2)/2, was previously performed at BNL with a result of 2.2 - 2.7 standard deviations above the Standard Model (SM) theoretical calculations. The same experimental apparatus is being planned to run in the new Muon Campus at Fermilab, where the muon beam is expected to have less pion contamination and the extended dataset may provide a possible 7.5σ deviation from the SM, creating a sensitive and complementary benchmark for proposed SM extensions. We report here on a preliminary study of the target subsystem where the apparatus is optimized for pions that have favorable phase space to create polarized daughter muons around the magic momentum of 3.094 GeV/c, which is needed by the downstream g 2 muon ring.

TUPPC043	Design of Accumulator and Compressor Rings for the Project-X Based Proton Driver	1260
	Y. Alexahin, D.V. Neuffer Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. A Muon Collider (MC) and Neutrino Factory (NF), which may be considered as a step towards MC, both require high-power (~4 MW) proton driver providing short (<1m) bunches for muon production. However, the driver repetition rate required for these two machines is different: ~15 Hz for MC and ~60 Hz for NF. This difference necessitates employing two separate rings: one for accumulation of the proton beam from the Project-X linac in a few (e.g., 4) long bunches, the other for bunch compression - one by one for NF or all at a time for MC with simultaneous delivery to the target. The lattice requirements for these two rings are different: the momentum compaction factor in the accumulator ring should be large (and possibly negative) to avoid the microwave instability, while the compressor ring can be nearly isochronous in order to limit the required RF voltage and reduce the dispersion contribution to the beam size. In the present report we consider ring lattice designs which achieve these goals.

TUPPD005	Design Concept for Nu-STORM: an Initial “Very Low-Energy Neutrino Factory”	1413
	D.V. Neuffer, A.D. Bross, S. Geer, A. Liu, M. Popovic Fermilab, Batavia, USA C.M. Ankenbrandt, T.J. Roberts Muons, Inc, Batavia, USA
	Funding: US DOE under contract DE-AC02-07CH11359 We present a design concept for a Nu-source from a STORage ring for Muons - NuSTORM. In this initial design a high-intensity proton beam produces ~5 GeV pions that provide muons that are captured using “stochastic injection” within a ~3.6 GeV racetrack storage ring. In “stochastic injection”, the ~53 GeV pion beam is transported from the target into the storage ring, dispersion-matched into a long straight section. (Circulating and injection orbits are separated by momentum.) Decays within that straight section provide muons that are within the ~2 GeV/c ring momentum acceptance and are stored for the muon lifetime of ~1000 turns. Muon (and pion) decays in the long straight sections provide neutrino beams that can be used for precision measurements of neutrino interactions, and neutrino oscillations or disappearance at L/E=~1 m/MeV. The facility is described and variations are discussed.

TUPPD006	IDR Neutrino Factory Front End and Variations	1416
	D.V. Neuffer Fermilab, Batavia, USA A. Alekou Imperial College of Science and Technology, Department of Physics, London, United Kingdom C.T. Rogers STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom P. Snopok IIT, Chicago, Illinois, USA C. Y. Yoshikawa Muons, Inc, Batavia, USA
	The (International Design Report) IDR neutrino factory scenario for capture, bunching, phase-energy rotation and initial cooling of muons produced from a proton source target is presented. It requires a drift section from the target, a bunching section and a phase-energy rotation section leading into the cooling channel. The rf frequency changes along the bunching and rotation transport in order to form the muons into a train of equal-energy bunches suitable for cooling and acceleration. This design is being explored within the IDR cost model. Important concerns are rf limitations and beam losses. Recent experiments on rf gradient limits suggest preferred configurations for the rf within the magnetic fields, and these considerations are incorporated into the front end design.

TUPPD007	Multiple Scattering Measurements in the MICE Experiment	1419
	T. Carlisle, J.H. Cobb JAI, Oxford, United Kingdom D.V. Neuffer Fermilab, Batavia, USA
	The international Muon Ionization Cooling Experiment (MICE), under construction at RAL, will test and characterize a prototype cooling channel for a future Neutrino Factory or Muon Collider. The cooling channel aims to achieve, using liquid hydrogen absorbers, a 10% reduction in transverse emittance. The change in 4D emittance will be determined with a relative accuracy of 1% by measuring muons individually. Muon detectors include two scintillating fibre trackers embedded within 4 T solenoid fields, TOF counters and a muon ranger. Step IV of MICE will begin in 2012, producing the experiment's first precise emittance-reduction measurements. Multiple scattering in candidate Step IV absorber materials was studied in G4MICE, based on GEANT4. Equilibrium emittances for low-Z materials from hydrogen to aluminium can be studied experimentally in Step IV of MICE, and compared with simulations.

TUPPD012	Complete Muon Cooling Channel Design and Simulations	1431
	C. Y. Yoshikawa, C.M. Ankenbrandt, R.P. Johnson Muons, Inc, Batavia, USA Y.S. Derbenev, V.S. Morozov JLAB, Newport News, Virginia, USA D.V. Neuffer, K. Yonehara Fermilab, Batavia, USA
	Considerable progress has been made in developing promising subsystems for muon beam cooling channels to provide the extraordinary reduction of emittances required for an energy-frontier muon collider. However, it has not yet been demonstrated that the various proposed cooling subsystems can be consolidated into an integrated end-to-end design. Presented here are concepts to address the matching of transverse emittances between subsystems through an extension of the theoretical framework of the Helical Cooling Channel (HCC), which allows a general analytical approach to guide the transition from one set of cooling channel parameters to another.

TUPPD013	Bunch Coalescing in a Helical Channel	1434
	C. Y. Yoshikawa, C.M. Ankenbrandt Muons, Inc, Batavia, USA D.V. Neuffer, K. Yonehara Fermilab, Batavia, USA
	Funding: Supported in part by SBIR Grant 4725 · 09SC02739. A high-luminosity Muon Collider requires bunch recombination for optimal luminosity. In this paper, we take advantage of the large slip factor in a helical transport channel (HTC) to coalesce bunches of muons into a single one over a shorter distance than can be achieved over a straight channel. The coalescing subsystem that is designed to merge 9 bunches has a horizontal length of ~105m and is able to achieve efficiencies of 99.7%, 98.4%, and 94.2% for 9, 11, and 13 bunches, respectively, where each bunch has emittances expected at the end of an HCC. Simplified designs incorporating fill factors for RF cavities of ~25% and ~50% obtained efficiencies of 96%, 94-95%, and 90-91% for 9, 11, and 13 bunches, respectively. The efficiencies above do not include decay losses, which would be ~8% for muons with kinetic energy of 200 MeV.

TUPPR011	Six-dimensional Bunch Merging for Muon Collider Cooling	1831
	R.B. Palmer, R.C. Fernow BNL, Upton, Long Island, New York, USA D.V. Neuffer Fermilab, Batavia, USA
	Funding: Work supported by US Department of Energy under contracts DE-AC02-98CH10886 and DE-AC02-07CH11359. Muons for a Muon Collider are diffusely produced from pion decay. They are first phase rotated into a trains of bunches. The trains are ionization cooled in all six dimensions until they can be merged into single bunches, one of each sign. They are then further cooled in six dimensions before acceleration and injection into the collider. This merging matches more efficiently into the second phase of cooling if the merging is also in six dimensions. A scheme to do this is proposed. Groups of 3, of the initial 12, bunches are merged longitudinally into 4 longer bunches, using rf with multiple harmonics. These 4 are then kicked into 4 separate (trombone) channels of different lengths to bring them to closely packed transverse locations at the same time. Here they are captured into a single bunch with now increased transverse emittance.

THPPR053	A CW FFAG for Proton Computed Tomography	4094
	C. Johnstone, D.V. Neuffer Fermilab, Batavia, USA H.L. Owen STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom P. Snopok IIT, Chicago, Illinois, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy An advantage of the cyclotron in proton therapy is the continuous (CW) beam output which reduces complexity and response time in the dosimetry requirements and beam controls. A CW accelerator requires isochronous particle orbits at all energies through the acceleration cycle and present compact isochronous cyclotrons for proton therapy reach only 250 MeV (kinetic energy) which is required for patient treatment, but low for full Proton Computed Tomography (PCT) capability. PCT specifications need 300-330 MeV in order for protons to transit the human body. Recent innovations in nonscaling FFAG design have achieved isochronous performance in a compact (~3 m radius) design at these higher energies. Preliminary isochronous designs are presented here. Lower energy beams can be efficiently extracted for patient treatment without changes to the acceleration cycle and magnet currents.

Paper

Title

Page

Use of Helical Transport Channels for Bunch Recombination

205

D.V. Neuffer, K. Yonehara
Fermilab, Batavia, USA
C.M. Ankenbrandt, C. Y. Yoshikawa
Muons, Inc, Batavia, USA

Cooling scenarios for a high-luminosity Muon Collider require bunch recombination for optimal luminosity. In this paper we describe a new method for bunch recombination. We combine the high-chronicity of a helical transport channel (HTC) with the high-frequency bunching and phase-energy rotation concept (time-reversed) to obtain a compact bunch recombination system adapted to a muon collider scenario. We first present an idealized 1-D system with multiple chronicity transports. We then implement the concept in a single-chronicity channel, obtaining bunch recombination of 13 200MHz-spaced bunches to a single collider-ready bunch within a compact transport with modest rf requirements. That example is demonstrated within G4BL 3-D simulations. Variations and adaptations for different recombination requirements are discussed.

MOPPC041

Control of Beam Losses in the Front End for the Neutrino Factory

223

C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
D.V. Neuffer
Fermilab, Batavia, USA
P. Snopok
IIT, Chicago, Illinois, USA

The Neutrino Factory produces neutrinos by muon decay in a storage ring. Pions are produced by firing high energy protons onto a target. Pions decay to muons, which are captured and accelerated to high energy. The target produces additionally a large background that is deposited in the muon capture front end and subsequent components. The implications of energy deposition in the front end lattice for the Neutrino Factory are addressed. Several approaches to mitigating the effect are proposed and discussed, including proton absorbers, chicane, and shielding.

MOPPD043

Novel Muon Beam Facilities for Project X at Fermilab

457

C.M. Ankenbrandt, R.J. Abrams, T.J. Roberts, C. Y. Yoshikawa
Muons, Inc, Batavia, USA
D.V. Neuffer
Fermilab, Batavia, USA

Innovative muon beam concepts for intensity-frontier experiments such as muon-to-electron conversion are described. Elaborating upon a previous single-beam idea, we have developed a design concept for a system to generate four high quality, low-energy muon beams (two of each sign) from a single beam of protons. As a first step, the production of pions by 1 and 3 GeV protons from the proposed Project X linac at Fermilab is being simulated and compared with the 8-GeV results from the previous study.

MOPPD044

Optimization of the Target Subsystem for the New g-2 Experiment

460

C. Y. Yoshikawa, C.M. Ankenbrandt
Muons, Inc, Batavia, USA
A.F. Leveling, N.V. Mokhov, J.P. Morgan, D.V. Neuffer, S.I. Striganov
Fermilab, Batavia, USA

A precision measurement of the muon anomalous magnetic moment, aμ = (g-2)/2, was previously performed at BNL with a result of 2.2 - 2.7 standard deviations above the Standard Model (SM) theoretical calculations. The same experimental apparatus is being planned to run in the new Muon Campus at Fermilab, where the muon beam is expected to have less pion contamination and the extended dataset may provide a possible 7.5σ deviation from the SM, creating a sensitive and complementary benchmark for proposed SM extensions. We report here on a preliminary study of the target subsystem where the apparatus is optimized for pions that have favorable phase space to create polarized daughter muons around the magic momentum of 3.094 GeV/c, which is needed by the downstream g 2 muon ring.

TUPPC043

Design of Accumulator and Compressor Rings for the Project-X Based Proton Driver

1260

Y. Alexahin, D.V. Neuffer
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
A Muon Collider (MC) and Neutrino Factory (NF), which may be considered as a step towards MC, both require high-power (~4 MW) proton driver providing short (<1m) bunches for muon production. However, the driver repetition rate required for these two machines is different: ~15 Hz for MC and ~60 Hz for NF. This difference necessitates employing two separate rings: one for accumulation of the proton beam from the Project-X linac in a few (e.g., 4) long bunches, the other for bunch compression - one by one for NF or all at a time for MC with simultaneous delivery to the target. The lattice requirements for these two rings are different: the momentum compaction factor in the accumulator ring should be large (and possibly negative) to avoid the microwave instability, while the compressor ring can be nearly isochronous in order to limit the required RF voltage and reduce the dispersion contribution to the beam size. In the present report we consider ring lattice designs which achieve these goals.

TUPPD005

Design Concept for Nu-STORM: an Initial “Very Low-Energy Neutrino Factory”

1413

D.V. Neuffer, A.D. Bross, S. Geer, A. Liu, M. Popovic
Fermilab, Batavia, USA
C.M. Ankenbrandt, T.J. Roberts
Muons, Inc, Batavia, USA

Funding: US DOE under contract DE-AC02-07CH11359
We present a design concept for a Nu-source from a STORage ring for Muons - NuSTORM. In this initial design a high-intensity proton beam produces ~5 GeV pions that provide muons that are captured using “stochastic injection” within a ~3.6 GeV racetrack storage ring. In “stochastic injection”, the ~53 GeV pion beam is transported from the target into the storage ring, dispersion-matched into a long straight section. (Circulating and injection orbits are separated by momentum.) Decays within that straight section provide muons that are within the ~2 GeV/c ring momentum acceptance and are stored for the muon lifetime of ~1000 turns. Muon (and pion) decays in the long straight sections provide neutrino beams that can be used for precision measurements of neutrino interactions, and neutrino oscillations or disappearance at L/E=~1 m/MeV. The facility is described and variations are discussed.

TUPPD006

IDR Neutrino Factory Front End and Variations

1416

D.V. Neuffer
Fermilab, Batavia, USA
A. Alekou
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
P. Snopok
IIT, Chicago, Illinois, USA
C. Y. Yoshikawa
Muons, Inc, Batavia, USA

The (International Design Report) IDR neutrino factory scenario for capture, bunching, phase-energy rotation and initial cooling of muons produced from a proton source target is presented. It requires a drift section from the target, a bunching section and a phase-energy rotation section leading into the cooling channel. The rf frequency changes along the bunching and rotation transport in order to form the muons into a train of equal-energy bunches suitable for cooling and acceleration. This design is being explored within the IDR cost model. Important concerns are rf limitations and beam losses. Recent experiments on rf gradient limits suggest preferred configurations for the rf within the magnetic fields, and these considerations are incorporated into the front end design.

TUPPD007

Multiple Scattering Measurements in the MICE Experiment

1419

T. Carlisle, J.H. Cobb
JAI, Oxford, United Kingdom
D.V. Neuffer
Fermilab, Batavia, USA

The international Muon Ionization Cooling Experiment (MICE), under construction at RAL, will test and characterize a prototype cooling channel for a future Neutrino Factory or Muon Collider. The cooling channel aims to achieve, using liquid hydrogen absorbers, a 10% reduction in transverse emittance. The change in 4D emittance will be determined with a relative accuracy of 1% by measuring muons individually. Muon detectors include two scintillating fibre trackers embedded within 4 T solenoid fields, TOF counters and a muon ranger. Step IV of MICE will begin in 2012, producing the experiment's first precise emittance-reduction measurements. Multiple scattering in candidate Step IV absorber materials was studied in G4MICE, based on GEANT4. Equilibrium emittances for low-Z materials from hydrogen to aluminium can be studied experimentally in Step IV of MICE, and compared with simulations.

TUPPD012

Complete Muon Cooling Channel Design and Simulations

1431

C. Y. Yoshikawa, C.M. Ankenbrandt, R.P. Johnson
Muons, Inc, Batavia, USA
Y.S. Derbenev, V.S. Morozov
JLAB, Newport News, Virginia, USA
D.V. Neuffer, K. Yonehara
Fermilab, Batavia, USA

Considerable progress has been made in developing promising subsystems for muon beam cooling channels to provide the extraordinary reduction of emittances required for an energy-frontier muon collider. However, it has not yet been demonstrated that the various proposed cooling subsystems can be consolidated into an integrated end-to-end design. Presented here are concepts to address the matching of transverse emittances between subsystems through an extension of the theoretical framework of the Helical Cooling Channel (HCC), which allows a general analytical approach to guide the transition from one set of cooling channel parameters to another.

TUPPD013

Bunch Coalescing in a Helical Channel

1434

C. Y. Yoshikawa, C.M. Ankenbrandt
Muons, Inc, Batavia, USA
D.V. Neuffer, K. Yonehara
Fermilab, Batavia, USA

Funding: Supported in part by SBIR Grant 4725 · 09SC02739.
A high-luminosity Muon Collider requires bunch recombination for optimal luminosity. In this paper, we take advantage of the large slip factor in a helical transport channel (HTC) to coalesce bunches of muons into a single one over a shorter distance than can be achieved over a straight channel. The coalescing subsystem that is designed to merge 9 bunches has a horizontal length of ~105m and is able to achieve efficiencies of 99.7%, 98.4%, and 94.2% for 9, 11, and 13 bunches, respectively, where each bunch has emittances expected at the end of an HCC. Simplified designs incorporating fill factors for RF cavities of ~25% and ~50% obtained efficiencies of 96%, 94-95%, and 90-91% for 9, 11, and 13 bunches, respectively. The efficiencies above do not include decay losses, which would be ~8% for muons with kinetic energy of 200 MeV.

TUPPR011

Six-dimensional Bunch Merging for Muon Collider Cooling

1831

R.B. Palmer, R.C. Fernow
BNL, Upton, Long Island, New York, USA
D.V. Neuffer
Fermilab, Batavia, USA

Funding: Work supported by US Department of Energy under contracts DE-AC02-98CH10886 and DE-AC02-07CH11359.
Muons for a Muon Collider are diffusely produced from pion decay. They are first phase rotated into a trains of bunches. The trains are ionization cooled in all six dimensions until they can be merged into single bunches, one of each sign. They are then further cooled in six dimensions before acceleration and injection into the collider. This merging matches more efficiently into the second phase of cooling if the merging is also in six dimensions. A scheme to do this is proposed. Groups of 3, of the initial 12, bunches are merged longitudinally into 4 longer bunches, using rf with multiple harmonics. These 4 are then kicked into 4 separate (trombone) channels of different lengths to bring them to closely packed transverse locations at the same time. Here they are captured into a single bunch with now increased transverse emittance.

THPPR053

A CW FFAG for Proton Computed Tomography

4094

C. Johnstone, D.V. Neuffer
Fermilab, Batavia, USA
H.L. Owen
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
P. Snopok
IIT, Chicago, Illinois, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
An advantage of the cyclotron in proton therapy is the continuous (CW) beam output which reduces complexity and response time in the dosimetry requirements and beam controls. A CW accelerator requires isochronous particle orbits at all energies through the acceleration cycle and present compact isochronous cyclotrons for proton therapy reach only 250 MeV (kinetic energy) which is required for patient treatment, but low for full Proton Computed Tomography (PCT) capability. PCT specifications need 300-330 MeV in order for protons to transit the human body. Recent innovations in nonscaling FFAG design have achieved isochronous performance in a compact (~3 m radius) design at these higher energies. Preliminary isochronous designs are presented here. Lower energy beams can be efficiently extracted for patient treatment without changes to the acceleration cycle and magnet currents.