IPAC2017 - List of Authors (Johnson, R.P.)

Paper	Title	Page
MOPAB015	Optimization of a Skew Parametric Resonance Ionization Cooling Channel Using Genetic Algorithm	111
	Y. Bao UCR, Riverside, California, USA A. Afanasev GWU, Washington, USA Y.S. Derbenev, V.S. Morozov, A.V. Sy JLab, Newport News, Virginia, USA R.P. Johnson Muons, Inc, Illinois, USA
	Funding: This work is supported by Muons Inc. Skew Parametric-resonance Ionization Cooling (Skew PIC) is designed for the final 6D cooling of a high-luminosity muon collider. Tracking of muons in such a channel has been modeled in MADX and matter-dominated simulation tool G4beanline in previous studies. In this work, we developed an optimization code based on Genetic Algorithm (GA). We optimized the cooling channel and increased the acceptance of the channel by using the GA code.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB015
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB144	Residual-Gas Beam Profile Monitors for Intense Beams in Transfer Lines	469
	R.J. Abrams, M.A. Cummings, V.G. Dudnikov, R.P. Johnson Muons, Inc, Illinois, USA M. Popovic Fermilab, Batavia, Illinois, USA
	Muons, Inc. proposes to develop a Residual-Gas Beam Profile Monitor for Transfer Lines with pulse-to-pulse precision of better than 0.1 mm in position and size that will operate over a wide range of proton beam intensities including those needed for multi-MW beams of future facilities. Traditional solid-based beam intercepting instrumentation produces unallowable levels of radiation at high powers. Our alternative approach is to use a low mass residual-gas profile monitor, where ionization electrons are collected along extended magnetic field lines and the gas composition and pressure in the beam pipe are locally controlled to minimize unwanted radiation and to improve resolution. Beam Induced Fluorescence profile monitor with mirascope light collection is proposed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB144
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB153	R&D of a Gas-Filled RF Beam Profile Monitor for Intense Neutrino Beam Experiments	491
	K. Yonehara, M. Backfish, A. Moretti, A.V. Tollestrup, A.C. Watts, R.M. Zwaska Fermilab, Batavia, Illinois, USA R.J. Abrams, M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer Muons, Inc, Illinois, USA Q. Liu Case Western Reserve University, Cleveland, USA
	Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013764. A MW-power beam facility is desired to produce an intense neutrino beam for study of fundamental particle physics. It is a critical challenge to measure beam profile in extreme radiation environments. To this end, a novel beam profile monitor based on a gas-filled multi-RF cavity is proposed. Charged particles through the gas-filled RF generate plasma that changes the gas permittivity. The modulated RF signal in the cavity due to the permittivity shift will be measured to reconstruct the flux of charged particles in the cavity. The demonstration is proposed to validate the concept of the monitor. We report the progress of the demonstration test.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB153
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB137	Cold Muonium Negative Ion Production	2898
	V.G. Dudnikov, M.A. Cummings, R.P. Johnson Muons, Inc, Illinois, USA A.V. Dudnikov BINP SB RAS, Novosibirsk, Russia
	Charged muons as Muonium negative ions (consisting of positive Mu-meson and 2 electrons) have affinity S=0.75 eV. Muonium have ionization energy I=13.6 eV. Muonium negative ions were observed in 1987 [10, 11] by interaction of muons with a foil. In these work an efficiency of transformation of mu mesons to negative musonium ions were very low 10^-4. However, with using Tungsten or palladium single crystal with deposition cesium it can be improved up to 40-50%.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB137
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPIK116	Aberration Compensation in a Skew Parametric-Resonance Ionization Cooling Channel	3221
	A.V. Sy, Y.S. Derbenev, V.S. Morozov JLab, Newport News, Virginia, USA A. Afanasev GWU, Washington, USA Y. Bao UCR, Riverside, California, USA R.P. Johnson Muons, Inc, Illinois, USA
	Funding: This work was supported in part by U.S. DOE STTR Grant DE-SC0005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Skew Parametric-resonance Ionization Cooling (Skew PIC) represents a novel method for focusing of highly divergent particle beams, as in the final 6D cooling stage of a high-luminosity muon collider. In the muon collider concept, the resultant equilibrium transverse emittances from cooling with Skew PIC are an order of magnitude smaller than in conventional ionization cooling. The concept makes use of coupling of the transverse dynamic behavior, and the linear dynamics are well-behaved with good agreement between analytic solutions and simulation results. Compared to the uncoupled system, coupling of the transverse dynamic behavior purports to reduce the number of multipoles required for aberration compensation while also avoiding unwanted resonances. Aberration compensation is more complicated in the coupled case, especially in the high-luminosity muon collider application where equilibrium angular spreads in the cooling channel are on the order of 200 mrad. We present recent progress on aberration compensation for control of highly divergent muon beams in the coupled correlated optics channel, and a simple cooling model to test the transverse acceptance of the channel.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK116
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB075	Accelerator Driven Subcritical Reactors for Profitable Disposition of Surplus Weapons-Grade Plutonium and Energy Generation	3883
	M.A. Cummings, R.J. Abrams, R.P. Johnson, T.J. Roberts Muons, Inc, Illinois, USA
	We discuss the GEMSTAR reactor concept, which addresses all historical reactor failures, which includes an internal spallation neutron target and high temperature molten salt fuel with continuous purging of volatile radioactive fission products such that the reactor contains less than a critical mass and almost a million times fewer volatile radioactive fission products than conventional reactors like those at Fukushima. GEMSTAR is a reactor that without redesign will burn spent nuclear fuel, natural uranium, thorium, or surplus weapons material. It will operate without the need for a critical core, fuel enrichment, or reprocessing making it an excellent candidate for export. While conventional nuclear reactors are becoming more and more difficult to license and expensive to build, SRF technology development is on a steep learning curve and the simplicity implied by subcritical operation will lead to reductions in regulatory hurdles and construction complexity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB075
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPIK121	Eddy Current Analysis for a 1.495 GHz Injection-Locked Magnetron	4383
	S.A. Kahn, A. Dudas, R.P. Johnson, M.L. Neubauer Muons, Inc, Illinois, USA R.A. Rimmer, H. Wang JLab, Newport News, Virginia, USA
	Funding: U.S. DOE SBIR/STTR grant DE-SC0013203 An injection-locked amplitude modulated magnetron is being developed as a reliable, efficient RF source that could replace klystrons used in particle accelerators. A trim magnetic coil is used to alter the magnetic field in conjunction with the anode voltage to maintain an SRF cavity voltage while the cavity is experiencing microphonics and changing beam loading. The microphonic noise modes have frequencies in the range 10-100 Hz. The changing magnetic field will induce transient eddy currents in the copper anode of the magnetron which will buck the field in the interaction region. This paper will describe the calculation and handling of the eddy currents in the magnetron.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK121
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPIK122	Methods of Phase and Power Control in Magnetron Transmitters for Superconducting Accelerators	4386
	G.M. Kazakevich, R.P. Johnson, M.L. Neubauer Muons, Inc, Illinois, USA V.A. Lebedev, W. Schappert, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Various methods of phase and power control in magnetron RF sources of superconducting accelerators intended for ADS-class projects were recently developed and studied with conventional 2.45 GHz, 1 kW, CW magnetrons operating in pulsed and CW regimes. Magnetron trans-mitters excited by a resonant (injection-locking) phase-modulated signal can provide phase and power control with the rates required for precise stabilization of phase and amplitude of the accelerating field in Superconducting RF (SRF) cavities of the intensity-frontier accelerators. An innovative technique that can significantly increase the magnetron transmitter efficiency at the wide-range power control required for superconducting accelerators was developed and verified with the 2.45 GHz magnetrons operating in CW and pulsed regimes. High efficiency magnetron transmitters of this type can significantly reduce the capital and operation costs of the ADS-class accelerator projects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK122
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Optimization of a Skew Parametric Resonance Ionization Cooling Channel Using Genetic Algorithm

111

Y. Bao
UCR, Riverside, California, USA
A. Afanasev
GWU, Washington, USA
Y.S. Derbenev, V.S. Morozov, A.V. Sy
JLab, Newport News, Virginia, USA
R.P. Johnson
Muons, Inc, Illinois, USA

Funding: This work is supported by Muons Inc.
Skew Parametric-resonance Ionization Cooling (Skew PIC) is designed for the final 6D cooling of a high-luminosity muon collider. Tracking of muons in such a channel has been modeled in MADX and matter-dominated simulation tool G4beanline in previous studies. In this work, we developed an optimization code based on Genetic Algorithm (GA). We optimized the cooling channel and increased the acceptance of the channel by using the GA code.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB015

Export •

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

MOPAB144

Residual-Gas Beam Profile Monitors for Intense Beams in Transfer Lines

469

R.J. Abrams, M.A. Cummings, V.G. Dudnikov, R.P. Johnson
Muons, Inc, Illinois, USA
M. Popovic
Fermilab, Batavia, Illinois, USA

Muons, Inc. proposes to develop a Residual-Gas Beam Profile Monitor for Transfer Lines with pulse-to-pulse precision of better than 0.1 mm in position and size that will operate over a wide range of proton beam intensities including those needed for multi-MW beams of future facilities. Traditional solid-based beam intercepting instrumentation produces unallowable levels of radiation at high powers. Our alternative approach is to use a low mass residual-gas profile monitor, where ionization electrons are collected along extended magnetic field lines and the gas composition and pressure in the beam pipe are locally controlled to minimize unwanted radiation and to improve resolution. Beam Induced Fluorescence profile monitor with mirascope light collection is proposed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB144

Export •

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

MOPAB153

R&D of a Gas-Filled RF Beam Profile Monitor for Intense Neutrino Beam Experiments

491

K. Yonehara, M. Backfish, A. Moretti, A.V. Tollestrup, A.C. Watts, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
R.J. Abrams, M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer
Muons, Inc, Illinois, USA
Q. Liu
Case Western Reserve University, Cleveland, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013764.
A MW-power beam facility is desired to produce an intense neutrino beam for study of fundamental particle physics. It is a critical challenge to measure beam profile in extreme radiation environments. To this end, a novel beam profile monitor based on a gas-filled multi-RF cavity is proposed. Charged particles through the gas-filled RF generate plasma that changes the gas permittivity. The modulated RF signal in the cavity due to the permittivity shift will be measured to reconstruct the flux of charged particles in the cavity. The demonstration is proposed to validate the concept of the monitor. We report the progress of the demonstration test.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB153

Export •

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

WEPAB137

Cold Muonium Negative Ion Production

2898

V.G. Dudnikov, M.A. Cummings, R.P. Johnson
Muons, Inc, Illinois, USA
A.V. Dudnikov
BINP SB RAS, Novosibirsk, Russia

Charged muons as Muonium negative ions (consisting of positive Mu-meson and 2 electrons) have affinity S=0.75 eV. Muonium have ionization energy I=13.6 eV. Muonium negative ions were observed in 1987 [10, 11] by interaction of muons with a foil. In these work an efficiency of transformation of mu mesons to negative musonium ions were very low 10^-4. However, with using Tungsten or palladium single crystal with deposition cesium it can be improved up to 40-50%.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB137

Export •

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

WEPIK116

Aberration Compensation in a Skew Parametric-Resonance Ionization Cooling Channel

3221

A.V. Sy, Y.S. Derbenev, V.S. Morozov
JLab, Newport News, Virginia, USA
A. Afanasev
GWU, Washington, USA
Y. Bao
UCR, Riverside, California, USA
R.P. Johnson
Muons, Inc, Illinois, USA

Funding: This work was supported in part by U.S. DOE STTR Grant DE-SC0005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Skew Parametric-resonance Ionization Cooling (Skew PIC) represents a novel method for focusing of highly divergent particle beams, as in the final 6D cooling stage of a high-luminosity muon collider. In the muon collider concept, the resultant equilibrium transverse emittances from cooling with Skew PIC are an order of magnitude smaller than in conventional ionization cooling. The concept makes use of coupling of the transverse dynamic behavior, and the linear dynamics are well-behaved with good agreement between analytic solutions and simulation results. Compared to the uncoupled system, coupling of the transverse dynamic behavior purports to reduce the number of multipoles required for aberration compensation while also avoiding unwanted resonances. Aberration compensation is more complicated in the coupled case, especially in the high-luminosity muon collider application where equilibrium angular spreads in the cooling channel are on the order of 200 mrad. We present recent progress on aberration compensation for control of highly divergent muon beams in the coupled correlated optics channel, and a simple cooling model to test the transverse acceptance of the channel.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK116

Export •

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

THPAB075

Accelerator Driven Subcritical Reactors for Profitable Disposition of Surplus Weapons-Grade Plutonium and Energy Generation

3883

M.A. Cummings, R.J. Abrams, R.P. Johnson, T.J. Roberts
Muons, Inc, Illinois, USA

We discuss the GEM*STAR reactor concept, which addresses all historical reactor failures, which includes an internal spallation neutron target and high temperature molten salt fuel with continuous purging of volatile radioactive fission products such that the reactor contains less than a critical mass and almost a million times fewer volatile radioactive fission products than conventional reactors like those at Fukushima. GEM*STAR is a reactor that without redesign will burn spent nuclear fuel, natural uranium, thorium, or surplus weapons material. It will operate without the need for a critical core, fuel enrichment, or reprocessing making it an excellent candidate for export. While conventional nuclear reactors are becoming more and more difficult to license and expensive to build, SRF technology development is on a steep learning curve and the simplicity implied by subcritical operation will lead to reductions in regulatory hurdles and construction complexity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB075

Export •

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

THPIK121

Eddy Current Analysis for a 1.495 GHz Injection-Locked Magnetron

4383

S.A. Kahn, A. Dudas, R.P. Johnson, M.L. Neubauer
Muons, Inc, Illinois, USA
R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA

Funding: U.S. DOE SBIR/STTR grant DE-SC0013203
An injection-locked amplitude modulated magnetron is being developed as a reliable, efficient RF source that could replace klystrons used in particle accelerators. A trim magnetic coil is used to alter the magnetic field in conjunction with the anode voltage to maintain an SRF cavity voltage while the cavity is experiencing microphonics and changing beam loading. The microphonic noise modes have frequencies in the range 10-100 Hz. The changing magnetic field will induce transient eddy currents in the copper anode of the magnetron which will buck the field in the interaction region. This paper will describe the calculation and handling of the eddy currents in the magnetron.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK121

Export •

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

THPIK122

Methods of Phase and Power Control in Magnetron Transmitters for Superconducting Accelerators

4386

G.M. Kazakevich, R.P. Johnson, M.L. Neubauer
Muons, Inc, Illinois, USA
V.A. Lebedev, W. Schappert, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Various methods of phase and power control in magnetron RF sources of superconducting accelerators intended for ADS-class projects were recently developed and studied with conventional 2.45 GHz, 1 kW, CW magnetrons operating in pulsed and CW regimes. Magnetron trans-mitters excited by a resonant (injection-locking) phase-modulated signal can provide phase and power control with the rates required for precise stabilization of phase and amplitude of the accelerating field in Superconducting RF (SRF) cavities of the intensity-frontier accelerators. An innovative technique that can significantly increase the magnetron transmitter efficiency at the wide-range power control required for superconducting accelerators was developed and verified with the 2.45 GHz magnetrons operating in CW and pulsed regimes. High efficiency magnetron transmitters of this type can significantly reduce the capital and operation costs of the ADS-class accelerator projects.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK122

Export •

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