IPAC2018 - List of Authors (Johnson, R.P.)

Paper	Title	Page
MOPML053	Mu*STAR Accelerator-Driven Subcritical Reactors Burning Spent Nuclear Fuel at Light-Water-Reactor Sites	524
	R.P. Johnson, R.J. Abrams, M.A. Cummings, T.J. Roberts Muons, Inc, Illinois, USA
	This project will use modeling and simulation tools to optimize many aspects of the MuSTAR design and begin to explore accident scenarios. At present we have a conceptual design of the accelerator, the reactor, the spallation target, and the fractional distillation to separate volatile fission products. Our GAIN project with ORNL is preparing a design of the Fuel Processing Plant that will convert spent nuclear fuel into the molten-salt fuel for MuSTAR. This includes all of the nuclear components, but not such things as the turbine and generator, physical plant, control and monitoring systems, etc. We currently have basic simulations of the reactor neutronics, and a start at calculating the fuel evolution. These have used MCNP and ORIGEN, and initial results have been reported1. This project will support the use of additional neutronics and multi-physics codes, enabling a much more thorough analysis of the system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML053
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MOPML054	Production and Collection of He-3 and Other Valuable Isotopes using Mu*STAR	527
	R.P. Johnson, R.J. Abrams, M.A. Cummings, T.J. Roberts Muons, Inc, Illinois, USA
	We propose an example facility based on GEM*STAR, an accelerator-driven molten-salt-fueled graphite-moderated thermal-spectrum reactor that can operate with different fissile fuels and uses a LiF-BeF2 molten eutectic carrier salt. In the first example, they propose using the 6Li in the LiF carrier to produce more than 2 kg/y of tritium (decaying to 3He with 12.3 year half-life) using a 2.5 MWb superconducting proton linac to drive the subcritical 500 MWt reactor burning surplus plutonium. The collection of other valuable fission-product radioisotopes like 133Xe will also benefit from the high temperature and continuous removal and separation afforded by fractional distillation
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML054
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WEPAG002	Tunable Q-Factor Gas-Filled RF Cavity	2064
SUSPF092	use link to see paper's listing under its alternate paper code
	M.D. Balcazar, A. Moretti, A.V. Tollestrup, A.C. Watts, K. Yonehara, R.M. Zwaska Fermilab, Batavia, Illinois, USA M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer Muons, Inc, Illinois, USA
	Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013795. Fermilab is the main institution to produce the most powerful and wide-spectrum neutrino beam. From that respective, a radiation robust beam diagnostic system is a critical element in order to maintain the quality of the neutrino beam. Within this context, a novel radiation-resistive beam profile monitor based on a gas-filled RF cavity has been proposed. The goal of this measurement is to study a tunable Q-factor RF cavity to determine the accuracy of the RF signal as a function of the quality factor. Specifically, the measurement error of the Q-factor in the RF calibration is investigated. Then, the RF system will be improved to minimize signal error.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAG002
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WEPAK001	Intense Neutrino Source Front End Beam Diagnostics System R&D	2077
	K. Yonehara, M.D. Balcazar, A. Moretti, A.V. Tollestrup, A.C. Watts, R.M. Zwaska Fermilab, Batavia, Illinois, USA M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer Muons, Inc, Illinois, USA
	Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013795. We overview the front end beam diagnostic system R&D to prepare operation of a multi-MW proton beam for intensity frontier Neutrino experiments. One of critical issues is shorter life time of a detector with higher beam intensity due to radiation damage. We show a possible improvement of the existing ion chamber based detector, and a study of a conceptually new radiation-robust detector which is based on a gas-filled RF resonator.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK001
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THPAL038	Phase Grouping of Larmor Electrons by a Synchronous Wave in Controlled Magnetrons	3723
	G.M. Kazakevich, R.P. Johnson Muons, Inc, Illinois, USA V.A. Lebedev, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	A simplified analytical model based on the charge drift approximation has been developed. It considers the resonant interaction of the synchronous wave with the flow of Larmor electrons in a magnetron. The model predicts stable coherent generation of the tube above and below the threshold of self-excitation. This occurs if the magnetron is driven by a sufficient resonant injected signal (up to -10 dB). The model substantiates precise stability, high efficiency and low noise at the range of the magnetron power control over 10 dB by variation of the magnetron current. The model and the verifying experiments with 2.45 GHz, 1 kW magnetrons are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL038
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THPAL039	Improved Magnetron Stability and Reduced Noise in Efficient Transmitters for Superconducting Accelerators	3726
	G.M. Kazakevich, R.P. Johnson Muons, Inc, Illinois, USA V.A. Lebedev, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	State of the art high-current superconducting accelerators require efficient RF sources with a fast dynamic phase and power control. This allows for compensation of the phase and amplitude deviations of the accelerating volt-age in the Superconducting RF (SRF) cavities caused by microphonics, etc. Efficient magnetron transmitters with fast phase and power control are attractive RF sources for this application. They are more cost effective than traditional RF sources such as klystrons, IOTs and solid-state amplifiers used with large scale accelerator projects. However, unlike traditional RF sources, controlled magnetrons operate as forced oscillators. Study of the impact of the controlling signal on magnetron stability, noise and efficiency is therefore important. This paper discusses experiments with 2.45 GHz, 1 kW tubes and verifies our analytical model which is based on the charge drift approximation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL039
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THPMK007	Surface Acoustic Wave Enhancement of Photocathodes	4304
	R.P. Johnson Muons, Inc, Illinois, USA A. Afanasev, B. Dong, M. E. Zaghloul GWU, Washington, USA
	Funding: Work supported by DOE HEP STTR Grant DE-SC0017831 Numerical simulations and fabrication techniques are being used to investigate the use of surface acoustic waves to suppress electron-hole recombination on the surface of GaAs photocathodes in order to increase the quantum efficiency for polarized and unpolarized electron beam generation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK007
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THPML009	Polarized Deuteron Negative Ion Source for Nuclear Physics Applications	4665
	V.G. Dudnikov, M.A. Cummings, R.P. Johnson Muons, Inc, Illinois, USA A.V. Sy JLab, Newport News, Virginia, USA
	The proposed U.S. Electron-Ion Collider (EIC) provides a unique tool to explore the next frontier in Quantum Chromodynamics, the dependence of hadron structure on the dynamics of gluons and sea quarks. Polarized beams are essential to these studies; understanding of the hadron structure cannot be achieved without knowledge of the spin. The existing EIC concepts utilize both polarized electrons and polarized protons/light ion species to probe the sea quark and gluon distributions. Polarized deuterons provide an especially unique system for study by essentially providing a combination of quark and nuclear physics. We note that there are currently no operational polarized deuteron beam sources in the United States. This polarized deuteron source can serve as a polarized deuteron injector for a future EIC, with additional applications in polarimetry and polarized gas targets for experiments at CEBAF or RHIC and would be very useful for our future facilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML009
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Mu*STAR Accelerator-Driven Subcritical Reactors Burning Spent Nuclear Fuel at Light-Water-Reactor Sites

524

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

This project will use modeling and simulation tools to optimize many aspects of the Mu*STAR design and begin to explore accident scenarios. At present we have a conceptual design of the accelerator, the reactor, the spallation target, and the fractional distillation to separate volatile fission products. Our GAIN project with ORNL is preparing a design of the Fuel Processing Plant that will convert spent nuclear fuel into the molten-salt fuel for Mu*STAR. This includes all of the nuclear components, but not such things as the turbine and generator, physical plant, control and monitoring systems, etc. We currently have basic simulations of the reactor neutronics, and a start at calculating the fuel evolution. These have used MCNP and ORIGEN, and initial results have been reported1. This project will support the use of additional neutronics and multi-physics codes, enabling a much more thorough analysis of the system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML053

Export •

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

MOPML054

Production and Collection of He-3 and Other Valuable Isotopes using Mu*STAR

527

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

We propose an example facility based on GEM*STAR, an accelerator-driven molten-salt-fueled graphite-moderated thermal-spectrum reactor that can operate with different fissile fuels and uses a LiF-BeF2 molten eutectic carrier salt. In the first example, they propose using the 6Li in the LiF carrier to produce more than 2 kg/y of tritium (decaying to 3He with 12.3 year half-life) using a 2.5 MWb superconducting proton linac to drive the subcritical 500 MWt reactor burning surplus plutonium. The collection of other valuable fission-product radioisotopes like 133Xe will also benefit from the high temperature and continuous removal and separation afforded by fractional distillation

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML054

Export •

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

WEPAG002

Tunable Q-Factor Gas-Filled RF Cavity

2064

SUSPF092

use link to see paper's listing under its alternate paper code

M.D. Balcazar, A. Moretti, A.V. Tollestrup, A.C. Watts, K. Yonehara, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer
Muons, Inc, Illinois, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013795.
Fermilab is the main institution to produce the most powerful and wide-spectrum neutrino beam. From that respective, a radiation robust beam diagnostic system is a critical element in order to maintain the quality of the neutrino beam. Within this context, a novel radiation-resistive beam profile monitor based on a gas-filled RF cavity has been proposed. The goal of this measurement is to study a tunable Q-factor RF cavity to determine the accuracy of the RF signal as a function of the quality factor. Specifically, the measurement error of the Q-factor in the RF calibration is investigated. Then, the RF system will be improved to minimize signal error.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAG002

Export •

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

WEPAK001

Intense Neutrino Source Front End Beam Diagnostics System R&D

2077

K. Yonehara, M.D. Balcazar, A. Moretti, A.V. Tollestrup, A.C. Watts, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer
Muons, Inc, Illinois, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013795.
We overview the front end beam diagnostic system R&D to prepare operation of a multi-MW proton beam for intensity frontier Neutrino experiments. One of critical issues is shorter life time of a detector with higher beam intensity due to radiation damage. We show a possible improvement of the existing ion chamber based detector, and a study of a conceptually new radiation-robust detector which is based on a gas-filled RF resonator.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK001

Export •

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

THPAL038

Phase Grouping of Larmor Electrons by a Synchronous Wave in Controlled Magnetrons

3723

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

A simplified analytical model based on the charge drift approximation has been developed. It considers the resonant interaction of the synchronous wave with the flow of Larmor electrons in a magnetron. The model predicts stable coherent generation of the tube above and below the threshold of self-excitation. This occurs if the magnetron is driven by a sufficient resonant injected signal (up to -10 dB). The model substantiates precise stability, high efficiency and low noise at the range of the magnetron power control over 10 dB by variation of the magnetron current. The model and the verifying experiments with 2.45 GHz, 1 kW magnetrons are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL038

Export •

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

THPAL039

Improved Magnetron Stability and Reduced Noise in Efficient Transmitters for Superconducting Accelerators

3726

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

State of the art high-current superconducting accelerators require efficient RF sources with a fast dynamic phase and power control. This allows for compensation of the phase and amplitude deviations of the accelerating volt-age in the Superconducting RF (SRF) cavities caused by microphonics, etc. Efficient magnetron transmitters with fast phase and power control are attractive RF sources for this application. They are more cost effective than traditional RF sources such as klystrons, IOTs and solid-state amplifiers used with large scale accelerator projects. However, unlike traditional RF sources, controlled magnetrons operate as forced oscillators. Study of the impact of the controlling signal on magnetron stability, noise and efficiency is therefore important. This paper discusses experiments with 2.45 GHz, 1 kW tubes and verifies our analytical model which is based on the charge drift approximation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL039

Export •

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

THPMK007

Surface Acoustic Wave Enhancement of Photocathodes

4304

R.P. Johnson
Muons, Inc, Illinois, USA
A. Afanasev, B. Dong, M. E. Zaghloul
GWU, Washington, USA

Funding: Work supported by DOE HEP STTR Grant DE-SC0017831
Numerical simulations and fabrication techniques are being used to investigate the use of surface acoustic waves to suppress electron-hole recombination on the surface of GaAs photocathodes in order to increase the quantum efficiency for polarized and unpolarized electron beam generation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK007

Export •

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

THPML009

Polarized Deuteron Negative Ion Source for Nuclear Physics Applications

4665

V.G. Dudnikov, M.A. Cummings, R.P. Johnson
Muons, Inc, Illinois, USA
A.V. Sy
JLab, Newport News, Virginia, USA

The proposed U.S. Electron-Ion Collider (EIC) provides a unique tool to explore the next frontier in Quantum Chromodynamics, the dependence of hadron structure on the dynamics of gluons and sea quarks. Polarized beams are essential to these studies; understanding of the hadron structure cannot be achieved without knowledge of the spin. The existing EIC concepts utilize both polarized electrons and polarized protons/light ion species to probe the sea quark and gluon distributions. Polarized deuterons provide an especially unique system for study by essentially providing a combination of quark and nuclear physics. We note that there are currently no operational polarized deuteron beam sources in the United States. This polarized deuteron source can serve as a polarized deuteron injector for a future EIC, with additional applications in polarimetry and polarized gas targets for experiments at CEBAF or RHIC and would be very useful for our future facilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML009

Export •

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