IPAC2015 - List of Authors (Flanagan, G.)

Paper	Title	Page
MOPWI018	New Hadron Monitor By Using A Gas-Filled RF Resonator	1189
	K. Yonehara, A.V. Tollestrup, R.M. Zwaska Fermilab, Batavia, Illinois, USA G. Fasce CNI, Roma, Italy G. Flanagan, R.P. Johnson Muons, Inc, Illinois, USA
	It is trend to build an intense neutrino beam facility for the fundamental physics research, e.g. LBNF at Fermilab, T2K at KEK, and CNGS at CERN. They have investigated a hadron monitor to diagnose the primary/secondary beam quality. The existing hadron monitor based on an ionization chamber is not robust in the high-radiation environment vicinity of MW-class secondary particle production targets. We propose a gas-filled RF resonator to use as the hadron monitor since it is simple and hence radiation robust in this environment. When charged particles pass through the resonator they produce ionized plasma via the Coulomb interaction with the inert gas. The beam-induced plasma changes the permittivity of inert gas. As a result, a resonant frequency in the resonator shifts with the amount of ionized electrons. The radiation sensitivity is adjustable by the inert gas pressure and the RF amplitude. The hadron profile will be reconstructed with a tomography technique in the hodoscope which consists of X, Y, and theta layers by using a strip-shaped gas resonator. The sensitivity and possible system design will be shown in this presentation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI018
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TUPWI022	GEM*STAR Accelerator-Driven Subcritical System for Improved Safety, Waste Management, and Plutonium Disposition	2289
	R.P. Johnson, R.J. Abrams, M.A.C. Cummings, G. Flanagan, T.J. Roberts Muons, Inc, Illinois, USA C. Bowman ADNA, Los Alamos, New Mexico, USA R.B. Vogelaar Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
	Operation of high-power SRF particle accelerators at two US national laboratories allows us to consider a less-expensive nuclear reactor that operates without the need for a critical core, fuel enrichment, or reprocessing. A multipurpose reactor design that takes advantage of this new accelerator capability includes an internal spallation neutron target and high-temperature molten-salt fuel with continuous purging of volatile radioactive fission products. 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. We describe GEMSTAR , a reactor that without redesign will burn spent nuclear fuel, natural uranium, thorium, or surplus weapons material. A first application is to burn 34 tonnes of excess weapons grade plutonium as an important step in nuclear disarmament under the 2000 Plutonium Management and Disposition Agreement *. The process heat generated by this W-Pu can be used for the Fischer-Tropsch conversion of natural gas and renewable carbon into 42 billion gallons of low-CO2-footprint, drop-in, synthetic diesel fuel for the DOD. Charles D. Bowman, R. Bruce Vogelaar, et al., Handbook of Nuclear Engineering, Springer Science+Business Media LLC (2010). ** http://www.state.gov/r/pa/prs/ps/2010/04/140097.htm
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI022
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WEPTY030	Breakdown Characterization in 805 MHz Pillbox-like Cavity in Strong Magnetic Fields	3335
	A.V. Kochemirovskiy, D.L. Bowring, A. Moretti, D.W. Peterson, K. Yonehara Fermilab, Batavia, Illinois, USA M. Chung UNIST, Ulsan, Republic of Korea G. Flanagan, G.M. Kazakevich Muons, Inc, Illinois, USA B.T. Freemire IIT, Chicago, Illinois, USA A.V. Kochemirovskiy University of Chicago, Chicago, Illinois, USA Y. Torun Illinois Institute of Technology, Chicago, Illlinois, USA
	RF Breakdown in strong magnetic fields has a negative impact on a cavity performance. The MuCool Test Area at Fermilab has unique capabilities that that allow us to study the effects of static magnetic field on RF cavity operation. We have tested an 805 MHz pillbox-like cavity in external magnetic fields up to 5T. Results confirm our basic model of breakdown in strong magnetic fields. We have measured maximum achievable surface gradient dependence on external static magnetic field. Damage inspection of cavity walls revealed a unique observed breakdown pattern. We present the analysis of breakdown damage distribution and propose the hypothesis to explain certain features of this distribution
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY030
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WEPTY033	A Concept for a High-field Helical Solenoid	3345
	S. Krave, N. Andreev, R. Bossert, M.L. Lopes, J.C. Tompkins, R. Wands Fermilab, Batavia, Illinois, USA G. Flanagan Muons, Inc, Illinois, USA K.E. Melconian Texas A&M University, College Station, Texas, USA
	Funding: Fermi Research Alliance under DOE Contract DE-AC02-07CH11359 Helical cooling channels have been proposed for highly efficient 6D muon cooling to produce the required helical solenoidal, dipole, and gradient field components. The channel is divided into sections, each subsequent section with higher field. Simulations have shown that for the high-field sections the use of Nb3Sn superconductor is needed. A continuous winding method and novel stainless steel collaring system has been developed for use in the high field section of a helical cooling channel. Each collar layer is identical, for ease of fabrication, and assembled by both flipping and rotating the subsequent layers. Mechanical and magnetic simulations were performed using a combination of ANSYS and OPERA. The winding and collaring method has been demonstrated on a four coil prototype using a Nb3Sn Rutherford cable. Details of the mechanical design, magnetic modeling, and winding method are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY033
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WEPTY059	Alternative Methods for Field Corrections in Helical Solenoids	3409
	K.E. Melconian Texas A&M University, College Station, Texas, USA G. Flanagan, S.A. Kahn Muons, Inc, Illinois, USA S. Krave, M.L. Lopes, J.C. Tompkins, K. Yonehara Fermilab, Batavia, Illinois, USA
	Funding: Fermi Research Alliance under DOE Contract DE-AC02-07CH11359 Helical cooling channels have been proposed for highly efficient 6D muon cooling. Helical solenoids produce solenoidal, helical dipole, and helical gradient field components. Previous studies explored the geometric tunability limits on these main field components. In this paper we present two alternative correction schemes, tilting the solenoids and the addition of helical lines, to reduce the required strength of the anti-solenoid and add an additional tuning knob.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY059
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WEPTY064	Thermal-mechanical Analysis of the FRIB Nuclear Fragment Separator Dipole Magnet	3425
	S.A. Kahn, A. Dudas, G. Flanagan Muons, Inc, Illinois, USA R.C. Gupta BNL, Upton, Long Island, New York, USA
	Funding: This work was supported by the U.S. Department of Energy under Grant DE-SC-0006273 Dipole magnets in the fragment separator region of the Facility for Rare Isotope Beams (FRIB) are critical elements used to select the desired isotopes. These magnets are subjected to high radiation and heat loads. High temperature superconductors (HTS), which have been shown to be radiation resistant and can operate at 40 K where heat removal is substantially more efficient than 4.5 K where conventional superconductors such as NbTi and Nb3Sn operate, are proposed for the coils. The magnet coils carry large current and will be subjected to large Lorentz forces that must be constrained to avoid distortions of the coils. It is desirable to minimize the use of organic materials in the fabrication of this magnet because of the radiation environment. This paper will describe an approach to support the coils to minimize coil deformation and cryogenic heat loss.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY064
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Paper

Title

Page

New Hadron Monitor By Using A Gas-Filled RF Resonator

1189

K. Yonehara, A.V. Tollestrup, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
G. Fasce
CNI, Roma, Italy
G. Flanagan, R.P. Johnson
Muons, Inc, Illinois, USA

It is trend to build an intense neutrino beam facility for the fundamental physics research, e.g. LBNF at Fermilab, T2K at KEK, and CNGS at CERN. They have investigated a hadron monitor to diagnose the primary/secondary beam quality. The existing hadron monitor based on an ionization chamber is not robust in the high-radiation environment vicinity of MW-class secondary particle production targets. We propose a gas-filled RF resonator to use as the hadron monitor since it is simple and hence radiation robust in this environment. When charged particles pass through the resonator they produce ionized plasma via the Coulomb interaction with the inert gas. The beam-induced plasma changes the permittivity of inert gas. As a result, a resonant frequency in the resonator shifts with the amount of ionized electrons. The radiation sensitivity is adjustable by the inert gas pressure and the RF amplitude. The hadron profile will be reconstructed with a tomography technique in the hodoscope which consists of X, Y, and theta layers by using a strip-shaped gas resonator. The sensitivity and possible system design will be shown in this presentation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI018

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TUPWI022

GEM*STAR Accelerator-Driven Subcritical System for Improved Safety, Waste Management, and Plutonium Disposition

2289

R.P. Johnson, R.J. Abrams, M.A.C. Cummings, G. Flanagan, T.J. Roberts
Muons, Inc, Illinois, USA
C. Bowman
ADNA, Los Alamos, New Mexico, USA
R.B. Vogelaar
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA

Operation of high-power SRF particle accelerators at two US national laboratories allows us to consider a less-expensive nuclear reactor that operates without the need for a critical core, fuel enrichment, or reprocessing. A multipurpose reactor design that takes advantage of this new accelerator capability includes an internal spallation neutron target and high-temperature molten-salt fuel with continuous purging of volatile radioactive fission products. 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. We describe GEM*STAR *, a reactor that without redesign will burn spent nuclear fuel, natural uranium, thorium, or surplus weapons material. A first application is to burn 34 tonnes of excess weapons grade plutonium as an important step in nuclear disarmament under the 2000 Plutonium Management and Disposition Agreement **. The process heat generated by this W-Pu can be used for the Fischer-Tropsch conversion of natural gas and renewable carbon into 42 billion gallons of low-CO2-footprint, drop-in, synthetic diesel fuel for the DOD.
* Charles D. Bowman, R. Bruce Vogelaar, et al., Handbook of Nuclear Engineering, Springer Science+Business Media LLC (2010).
** http://www.state.gov/r/pa/prs/ps/2010/04/140097.htm

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI022

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WEPTY030

Breakdown Characterization in 805 MHz Pillbox-like Cavity in Strong Magnetic Fields

3335

A.V. Kochemirovskiy, D.L. Bowring, A. Moretti, D.W. Peterson, K. Yonehara
Fermilab, Batavia, Illinois, USA
M. Chung
UNIST, Ulsan, Republic of Korea
G. Flanagan, G.M. Kazakevich
Muons, Inc, Illinois, USA
B.T. Freemire
IIT, Chicago, Illinois, USA
A.V. Kochemirovskiy
University of Chicago, Chicago, Illinois, USA
Y. Torun
Illinois Institute of Technology, Chicago, Illlinois, USA

RF Breakdown in strong magnetic fields has a negative impact on a cavity performance. The MuCool Test Area at Fermilab has unique capabilities that that allow us to study the effects of static magnetic field on RF cavity operation. We have tested an 805 MHz pillbox-like cavity in external magnetic fields up to 5T. Results confirm our basic model of breakdown in strong magnetic fields. We have measured maximum achievable surface gradient dependence on external static magnetic field. Damage inspection of cavity walls revealed a unique observed breakdown pattern. We present the analysis of breakdown damage distribution and propose the hypothesis to explain certain features of this distribution

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY030

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WEPTY033

A Concept for a High-field Helical Solenoid

3345

S. Krave, N. Andreev, R. Bossert, M.L. Lopes, J.C. Tompkins, R. Wands
Fermilab, Batavia, Illinois, USA
G. Flanagan
Muons, Inc, Illinois, USA
K.E. Melconian
Texas A&M University, College Station, Texas, USA

Funding: Fermi Research Alliance under DOE Contract DE-AC02-07CH11359
Helical cooling channels have been proposed for highly efficient 6D muon cooling to produce the required helical solenoidal, dipole, and gradient field components. The channel is divided into sections, each subsequent section with higher field. Simulations have shown that for the high-field sections the use of Nb3Sn superconductor is needed. A continuous winding method and novel stainless steel collaring system has been developed for use in the high field section of a helical cooling channel. Each collar layer is identical, for ease of fabrication, and assembled by both flipping and rotating the subsequent layers. Mechanical and magnetic simulations were performed using a combination of ANSYS and OPERA. The winding and collaring method has been demonstrated on a four coil prototype using a Nb3Sn Rutherford cable. Details of the mechanical design, magnetic modeling, and winding method are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY033

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WEPTY059

Alternative Methods for Field Corrections in Helical Solenoids

3409

K.E. Melconian
Texas A&M University, College Station, Texas, USA
G. Flanagan, S.A. Kahn
Muons, Inc, Illinois, USA
S. Krave, M.L. Lopes, J.C. Tompkins, K. Yonehara
Fermilab, Batavia, Illinois, USA

Funding: Fermi Research Alliance under DOE Contract DE-AC02-07CH11359
Helical cooling channels have been proposed for highly efficient 6D muon cooling. Helical solenoids produce solenoidal, helical dipole, and helical gradient field components. Previous studies explored the geometric tunability limits on these main field components. In this paper we present two alternative correction schemes, tilting the solenoids and the addition of helical lines, to reduce the required strength of the anti-solenoid and add an additional tuning knob.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY059

Export •

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

WEPTY064

Thermal-mechanical Analysis of the FRIB Nuclear Fragment Separator Dipole Magnet

3425

S.A. Kahn, A. Dudas, G. Flanagan
Muons, Inc, Illinois, USA
R.C. Gupta
BNL, Upton, Long Island, New York, USA

Funding: This work was supported by the U.S. Department of Energy under Grant DE-SC-0006273
Dipole magnets in the fragment separator region of the Facility for Rare Isotope Beams (FRIB) are critical elements used to select the desired isotopes. These magnets are subjected to high radiation and heat loads. High temperature superconductors (HTS), which have been shown to be radiation resistant and can operate at 40 K where heat removal is substantially more efficient than 4.5 K where conventional superconductors such as NbTi and Nb3Sn operate, are proposed for the coils. The magnet coils carry large current and will be subjected to large Lorentz forces that must be constrained to avoid distortions of the coils. It is desirable to minimize the use of organic materials in the fabrication of this magnet because of the radiation environment. This paper will describe an approach to support the coils to minimize coil deformation and cryogenic heat loss.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY064

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