IPAC2021 - Classification: MC3: Novel Particle Sources and Acceleration Techniques / A09 Muon Accelerators and Neutrino Factories

Paper	Title	Page
MOXC02	Improved Lifetime of a High Spin Polarization Superlattice Photocathode	31
	L. Cultrera BNL, Upton, New York, USA
	Funding: Department of Energy under grant DE-SC0012704 Highly spin polarized electron beams are required for the operation of a wide range of accelerators and instruments. The production of such electrons requires the use of Negative Electron Affinity (NEA) activated GaAs-based cathodes operated in photoelectron guns. Because of their extreme sensitivity to poor vacuum conditions the degradation of the photoemission process is so strong that NEA activated GaAs-based photocathodes can only survive in the extreme vacuums typical of DC gun. State-of-the-art on photocathode technology for spin polarized beam productions are summarized. Recent results on the use of robust NEA coating based on the Cs-Te and Cs-Sb leading to improved operational lifetime of a high spin polarization photocathode are reviewed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXC02
About •	paper received ※ 20 May 2021 paper accepted ※ 19 July 2021 issue date ※ 19 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB132	The Multi-Mega-Watt Target Station for the European Spallation Source Neutrino Super Beam	466
	E. Baussan, E. Bouquerel, L. D’Alessi, M. Dracos, P. Poussot, J. Thomas, J. Wurtz, V. Zeter IPHC, Strasbourg Cedex 2, France P. Cupial, M. Koziol, L.J. Lacny, J. Snamina AGH University of Science and Technology, Kraków, Poland I. Efthymiopoulos CERN, Meyrin, Switzerland T. Tolba University of Hamburg, Hamburg, Germany
	Funding: This project has received funding from the European Union Horizon 2020 research and innovation program under grant agreement No 777419 and also by the Deutsche Forschungsgemeinschaft No 423761110. One of the next challenges in fundamental physics is to understand the origin of matter/antimatter asymmetry in the Universe. In particular, intense neutrinos could play an important role to elucidate this mystery and better understand the expansion of the Universe. The ESSnuSB collaboration proposes to use the proton linac of the European Spallation Source currently under construction in Lund (Sweden) to produce a very intense neutrino super beam, in parallel with the spallation neutron production. A very challenging part of the proposed facility is the Target Station which will have to afford 5 MW proton beam power. This poster will present the hadronic collector and the whole facility to produce the next generation of neutrino superbeam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB132
About •	paper received ※ 20 May 2021 paper accepted ※ 27 May 2021 issue date ※ 18 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB133	Recovering the Positron Beam After Muon Production in the Lemma Muon Source	470
	I. Drebot INFN-Milano, Milano, Italy M.E. Biagini, O.R. Blanco-García, A. Giribono, S. Guiducci, C. Vaccarezza, A. Variola INFN/LNF, Frascati, Italy S.M. Liuzzo ESRF, Grenoble, France
	In the LEMMA muon source proposal* a positron beam at 45 GeV is used to produce muons at threshold by interaction with some targets. In order to release the required intensity on the main positron source, orders of magnitude higher than the state of the art, the possibility to recover the primary positron beam after the interaction with the targets was studied. The particles distribution, with a strongly degraded energy spread after the interac- tion, was injected back into a low emittance, large energy acceptance 45 GeV ring. Studies of injection efficiency were performed. The possibility of compressing the beam in a linac before injection was also studied. As a result, even without compression, about 80% of the disrupted e⁺ beam can be injected back into the ring. * D. Alesini et al, "Positron driven muon source for a muon collider", arXiv:1905.05747v2 [physics.acc-ph], May 2019
	Poster MOPAB133 [4.171 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB133
About •	paper received ※ 17 May 2021 paper accepted ※ 24 May 2021 issue date ※ 20 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB134	Normalized Transverse Emittance Reduction via Ionization Cooling in MICE ’Flip Mode’	474
	P.B. Jurj Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Low emittance muon beams are central to the development of a Muon Collider and can significantly enhance the performance of a Neutrino Factory. The international Muon Ionization Cooling Experiment (MICE) has recorded several million individual muon tracks passing through a liquid hydrogen or a lithium hydride absorber and has demonstrated the ionization cooling of muon beams. Previous analysis used a restricted data set, and the beam matching was not perfect. In this analysis, beam sampling routines were employed to account for imperfections in beam matching at the entrance into the cooling channel and enable an improvement of the cooling measurement. A study of the normalized transverse emittance change in the MICE cooling channel set up in a flipped polarity magnetic field configuration is presented. Additionally, the evolution of the canonical angular momentum across the absorber is shown and the characteristics of the cooling effect are discussed.
	Poster MOPAB134 [1.821 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB134
About •	paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 27 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUXB07	High-Current H₂⁺ Beams from a Compact Cyclotron using RFQ Direct Injection	1301
	D. Winklehner, J.M. Conrad, D. Koser, J. Smolsky, L.H. Waites MIT, Cambridge, Massachusetts, USA
	Funding: This work was supported by NSF grants PHY-1505858 and PHY-1626069. For the IsoDAR neutrino experiment, we have developed a compact and cost-effective cyclotron-based driver to produce high current beams (cw proton beam currents of >10 mA at 60 MeV). This is a factor of 4 higher than the current state-of-the-art for cyclotrons and a factor of 10 compared to what is commercially available. All areas of physics that call for high cw currents can greatly benefit from this result; e.g. particle physics, medical isotope production, and energy research. This increase in beam current is possible in part because the cyclotron is designed to include and use vortex-motion, allowing clean extraction. Such a design process is only possible with the help of high-fidelity codes, like OPAL. Another novelty is the use of an RFQ embedded in the cyclotron yoke to bunch the beam during axial injection. Finally, using H²⁺ relieves some of the space charge constraints during injection. In this paper, we will give an overview of the project and then focus on the design and simulations of the cyclotron itself. We will describe the physics, computational tools, and simulation results. At the end, we will describe how we are including machine learning in the simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXB07
About •	paper received ※ 27 May 2021 paper accepted ※ 22 July 2021 issue date ※ 31 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB121	Plasma Muon Beam Cooling for HEP	3999
	M.A. Cummings, R.J. Abrams, R.P. Johnson, S.A. Kahn, T.J. Roberts Muons, Inc, Illinois, USA V.S. Morozov, A.V. Sy JLab, Newport News, Virginia, USA K. Yonehara Fermilab, Batavia, Illinois, USA
	Ionization cooling has the potential to shrink the phase space of a muon beam by a factor of 10⁶ within the muons’ short lifetime (2.2 µs) because the collision frequency in a cooling medium is extremely high compared to conventional beam cooling methods. It has been realized that ionization cooling inherently produces a plasma of free electrons inside the absorber material, and this plasma can have an important effect on the muon beam. In particular, under the right circumstances, it can both improve the rate of cooling and reduce the equilibrium emittance of the beam. This has the potential to improve the performance of muon facilities based on muon cooling; in particular a future muon collider. We describe how this project will integrate Plasma muon beam cooling into both the basic Helical Cooling Channel (HCC) and extreme Parametric-resonance Ionization Cooling (PIC) techniques. This potentially whole new approach to muon cooling has exciting prospects for significantly reduced muon beam emittance.
	Poster THPAB121 [1.214 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB121
About •	paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 11 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB124	Application of the FFA Concept to a Muon Collider Complex	4006
	S. Machida, J.-B. Lagrange STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom M.E. Topp-Mugglestone JAI, Oxford, United Kingdom
	Muon collider complex is one of the places where the concept of fixed field alternating gradient (FFA) optics can be applied with great benefits. Vertical excursion FFA (vFFA) provides the isochronous condition for the ultra-relativistic muon beams after pre-acceleration. Together with the fixed transverse tune, it will be an ideal accelerator of short-lived muon beams with no time variation of magnetic fields and RF frequency. Novel collider ring optics is a design based on skew quadrupole after extracting essential functions from vFFA. That enables control of the momentum compaction factor. Neutrinos from the continuing decay of muons are spread out with orbit wiggling in the vertical direction as well as horizontal. The paper discusses the underline principle and describes some design examples.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB124
About •	paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 28 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRXB05	Muon Ionization Cooling Experiment: Results & Prospects	4528
	C.T. Rogers STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	A high-energy muon collider could be the most powerful and cost-effective collider approach in the multi-TeV regime, and a neutrino source based on decay of an intense muon beam would be ideal for measurement of neutrino oscillation parameters. Muon beams may be created through the decay of pions produced in the interaction of a proton beam with a target. The muons are subsequently accelerated and injected into a storage ring where they decay producing a beam of neutrinos, or collide with counter-rotating antimuons. Cooling of the muon beam would enable more muons to be accelerated resulting in a more intense neutrino source and higher collider luminosity. Ionization cooling is the novel technique by which it is proposed to cool the beam. The Muon Ionization Cooling Experiment collaboration constructed a section of an ionization cooling channel and used it to provide the first demonstration of ionization cooling. Here the observation of ionization cooling is described. The cooling performance is studied for a variety of beam and magnetic field configurations. The outlook for muon ionization cooling demonstrations is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXB05
About •	paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 23 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Improved Lifetime of a High Spin Polarization Superlattice Photocathode

31

L. Cultrera
BNL, Upton, New York, USA

Funding: Department of Energy under grant DE-SC0012704
Highly spin polarized electron beams are required for the operation of a wide range of accelerators and instruments. The production of such electrons requires the use of Negative Electron Affinity (NEA) activated GaAs-based cathodes operated in photoelectron guns. Because of their extreme sensitivity to poor vacuum conditions the degradation of the photoemission process is so strong that NEA activated GaAs-based photocathodes can only survive in the extreme vacuums typical of DC gun. State-of-the-art on photocathode technology for spin polarized beam productions are summarized. Recent results on the use of robust NEA coating based on the Cs-Te and Cs-Sb leading to improved operational lifetime of a high spin polarization photocathode are reviewed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXC02

About •

paper received ※ 20 May 2021 paper accepted ※ 19 July 2021 issue date ※ 19 August 2021

Export •

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

MOPAB132

The Multi-Mega-Watt Target Station for the European Spallation Source Neutrino Super Beam

466

E. Baussan, E. Bouquerel, L. D’Alessi, M. Dracos, P. Poussot, J. Thomas, J. Wurtz, V. Zeter
IPHC, Strasbourg Cedex 2, France
P. Cupial, M. Koziol, L.J. Lacny, J. Snamina
AGH University of Science and Technology, Kraków, Poland
I. Efthymiopoulos
CERN, Meyrin, Switzerland
T. Tolba
University of Hamburg, Hamburg, Germany

Funding: This project has received funding from the European Union Horizon 2020 research and innovation program under grant agreement No 777419 and also by the Deutsche Forschungsgemeinschaft No 423761110.
One of the next challenges in fundamental physics is to understand the origin of matter/antimatter asymmetry in the Universe. In particular, intense neutrinos could play an important role to elucidate this mystery and better understand the expansion of the Universe. The ESSnuSB collaboration proposes to use the proton linac of the European Spallation Source currently under construction in Lund (Sweden) to produce a very intense neutrino super beam, in parallel with the spallation neutron production. A very challenging part of the proposed facility is the Target Station which will have to afford 5 MW proton beam power. This poster will present the hadronic collector and the whole facility to produce the next generation of neutrino superbeam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB132

About •

paper received ※ 20 May 2021 paper accepted ※ 27 May 2021 issue date ※ 18 August 2021

Export •

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

MOPAB133

Recovering the Positron Beam After Muon Production in the Lemma Muon Source

470

I. Drebot
INFN-Milano, Milano, Italy
M.E. Biagini, O.R. Blanco-García, A. Giribono, S. Guiducci, C. Vaccarezza, A. Variola
INFN/LNF, Frascati, Italy
S.M. Liuzzo
ESRF, Grenoble, France

In the LEMMA muon source proposal* a positron beam at 45 GeV is used to produce muons at threshold by interaction with some targets. In order to release the required intensity on the main positron source, orders of magnitude higher than the state of the art, the possibility to recover the primary positron beam after the interaction with the targets was studied. The particles distribution, with a strongly degraded energy spread after the interac- tion, was injected back into a low emittance, large energy acceptance 45 GeV ring. Studies of injection efficiency were performed. The possibility of compressing the beam in a linac before injection was also studied. As a result, even without compression, about 80% of the disrupted e⁺ beam can be injected back into the ring.
* D. Alesini et al, "Positron driven muon source for a muon collider", arXiv:1905.05747v2 [physics.acc-ph], May 2019

Poster MOPAB133 [4.171 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB133

About •

paper received ※ 17 May 2021 paper accepted ※ 24 May 2021 issue date ※ 20 August 2021

Export •

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

MOPAB134

Normalized Transverse Emittance Reduction via Ionization Cooling in MICE ’Flip Mode’

474

P.B. Jurj
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Low emittance muon beams are central to the development of a Muon Collider and can significantly enhance the performance of a Neutrino Factory. The international Muon Ionization Cooling Experiment (MICE) has recorded several million individual muon tracks passing through a liquid hydrogen or a lithium hydride absorber and has demonstrated the ionization cooling of muon beams. Previous analysis used a restricted data set, and the beam matching was not perfect. In this analysis, beam sampling routines were employed to account for imperfections in beam matching at the entrance into the cooling channel and enable an improvement of the cooling measurement. A study of the normalized transverse emittance change in the MICE cooling channel set up in a flipped polarity magnetic field configuration is presented. Additionally, the evolution of the canonical angular momentum across the absorber is shown and the characteristics of the cooling effect are discussed.

Poster MOPAB134 [1.821 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB134

About •

paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 27 August 2021

Export •

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

TUXB07

High-Current H₂⁺ Beams from a Compact Cyclotron using RFQ Direct Injection

1301

D. Winklehner, J.M. Conrad, D. Koser, J. Smolsky, L.H. Waites
MIT, Cambridge, Massachusetts, USA

Funding: This work was supported by NSF grants PHY-1505858 and PHY-1626069.
For the IsoDAR neutrino experiment, we have developed a compact and cost-effective cyclotron-based driver to produce high current beams (cw proton beam currents of >10 mA at 60 MeV). This is a factor of 4 higher than the current state-of-the-art for cyclotrons and a factor of 10 compared to what is commercially available. All areas of physics that call for high cw currents can greatly benefit from this result; e.g. particle physics, medical isotope production, and energy research. This increase in beam current is possible in part because the cyclotron is designed to include and use vortex-motion, allowing clean extraction. Such a design process is only possible with the help of high-fidelity codes, like OPAL. Another novelty is the use of an RFQ embedded in the cyclotron yoke to bunch the beam during axial injection. Finally, using H²⁺ relieves some of the space charge constraints during injection. In this paper, we will give an overview of the project and then focus on the design and simulations of the cyclotron itself. We will describe the physics, computational tools, and simulation results. At the end, we will describe how we are including machine learning in the simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXB07

About •

paper received ※ 27 May 2021 paper accepted ※ 22 July 2021 issue date ※ 31 August 2021

Export •

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

THPAB121

Plasma Muon Beam Cooling for HEP

3999

M.A. Cummings, R.J. Abrams, R.P. Johnson, S.A. Kahn, T.J. Roberts
Muons, Inc, Illinois, USA
V.S. Morozov, A.V. Sy
JLab, Newport News, Virginia, USA
K. Yonehara
Fermilab, Batavia, Illinois, USA

Ionization cooling has the potential to shrink the phase space of a muon beam by a factor of 10⁶ within the muons’ short lifetime (2.2 µs) because the collision frequency in a cooling medium is extremely high compared to conventional beam cooling methods. It has been realized that ionization cooling inherently produces a plasma of free electrons inside the absorber material, and this plasma can have an important effect on the muon beam. In particular, under the right circumstances, it can both improve the rate of cooling and reduce the equilibrium emittance of the beam. This has the potential to improve the performance of muon facilities based on muon cooling; in particular a future muon collider. We describe how this project will integrate Plasma muon beam cooling into both the basic Helical Cooling Channel (HCC) and extreme Parametric-resonance Ionization Cooling (PIC) techniques. This potentially whole new approach to muon cooling has exciting prospects for significantly reduced muon beam emittance.

Poster THPAB121 [1.214 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB121

About •

paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 11 August 2021

Export •

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

THPAB124

Application of the FFA Concept to a Muon Collider Complex

4006

S. Machida, J.-B. Lagrange
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
M.E. Topp-Mugglestone
JAI, Oxford, United Kingdom

Muon collider complex is one of the places where the concept of fixed field alternating gradient (FFA) optics can be applied with great benefits. Vertical excursion FFA (vFFA) provides the isochronous condition for the ultra-relativistic muon beams after pre-acceleration. Together with the fixed transverse tune, it will be an ideal accelerator of short-lived muon beams with no time variation of magnetic fields and RF frequency. Novel collider ring optics is a design based on skew quadrupole after extracting essential functions from vFFA. That enables control of the momentum compaction factor. Neutrinos from the continuing decay of muons are spread out with orbit wiggling in the vertical direction as well as horizontal. The paper discusses the underline principle and describes some design examples.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB124

About •

paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 28 August 2021

Export •

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

FRXB05

Muon Ionization Cooling Experiment: Results & Prospects

4528

C.T. Rogers
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

A high-energy muon collider could be the most powerful and cost-effective collider approach in the multi-TeV regime, and a neutrino source based on decay of an intense muon beam would be ideal for measurement of neutrino oscillation parameters. Muon beams may be created through the decay of pions produced in the interaction of a proton beam with a target. The muons are subsequently accelerated and injected into a storage ring where they decay producing a beam of neutrinos, or collide with counter-rotating antimuons. Cooling of the muon beam would enable more muons to be accelerated resulting in a more intense neutrino source and higher collider luminosity. Ionization cooling is the novel technique by which it is proposed to cool the beam. The Muon Ionization Cooling Experiment collaboration constructed a section of an ionization cooling channel and used it to provide the first demonstration of ionization cooling. Here the observation of ionization cooling is described. The cooling performance is studied for a variety of beam and magnetic field configurations. The outlook for muon ionization cooling demonstrations is discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXB05

About •

paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 23 August 2021

Export •

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