NAPAC2022 - List of Keywords (neutron)

Paper	Title	Other Keywords	Page
MOODE1	Applications of Particle Accelerators	linac, electron, site, target	1
	M. Uesaka JAEC, Tokyo, Japan
	Applications of particle accelerators amid global policies of carbon neutrality and economic security. are reviewed. Downsizing of high energy large scaled accelerators by advanced technologies enables a variety of medical and industrial uses. One of the highlights is upgrade of sustainable supply chain of medical radioisotopes by the best mix of research reactors and accelerators. 99Mo/99mTc for diagnosis are going to be produced by low enriched U reactor and proton-cyclotron, electron rhodotron and electron linac. Moreover, the theranostics by 177Lu (beta) and 211At/225Ac (alpha) are going to be realized. Proton-cyclotron and electron linac are expected to produce them soon. This new affordable radiation therapy should play an important role in the IAEA project of Rays of Hopes. Next, proof-of-principle trails of on-site bridge inspection of the portable X-band (9.3 GHz) electron linac X-ray/neutron sources are under way. The technical guideline for the practical inspection is to be formed in a couple of years. Ultimate micro-accelerator for microbeam applications is dielectric laser accelerator, such as ACHIP project. Updated projects and results are also introduced.
	Slides MOODE1 [3.065 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOODE1
About •	Received ※ 02 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 11 August 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPA02	Activation of the IBA Proteus One Proton Therapy Beamline Using BDSIM and FISPACT-II	proton, shielding, radiation, simulation	59
	E. Ramoisiaux, E. Gnacadja, C. Hernalsteens, N. Pauly, R. Tesse, M. Vanwelde ULB, Bruxelles, Belgium C. Hernalsteens CERN, Meyrin, Switzerland
	Cyclotron-based proton therapy systems generate large fluxes of secondary particles due to the beam interactions with the beamline elements, with the energy degrader being the dominant source. Compact systems exacerbate these challenges for concrete shielding and beamline element activation. Our implementation of the Rigorous Two-Step method uses Beam Delivery Simulation (BDSIM), a Geant4-based particle tracking code, for primary and secondary particles transport and fluence scoring, and FISPACT-II for time-dependent nuclear inventory and solving the rate equations. This approach is applied to the Ion Beam Applications (IBA) Proteus®ONE (P1) system, for which a complete model has been built, validated, and used for shielding activation simulations. We detail the first simulations of the activation on quadrupole magnets in high-fluence locations downstream of the degrader. Results show the evolution of the long-lived nuclide concentrations for short and long timescales throughout the facility lifetime for a typical operation scenario.
	Poster MOPA02 [0.553 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA02
About •	Received ※ 02 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 19 August 2022 — Issue date ※ 21 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUXD3	Production Pathways for Medically Interesting Isotopes	target, radiation, proton, isotope-production	271
	L. Rosado Del Rio University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico L.F. Dabill Coe College, Cedar Rapids, Iowa, USA A. Hutton JLab, Newport News, Virginia, USA
	Funding: LR was supported by the U.S. NSF REU at Old Dominion University Grant No. 1950141. AH was supported by the U.S. DOE, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177 Radioisotopes are commonly used in nuclear medicine for treating cancer and new, more effective treatment options are always desired. As a result, there is a national need for new radioisotopes and ways to produce them. A computer program was created that evaluates the daughters for all known reactions of projectiles (gamma rays, protons or neutrons) with every stable target isotope by comparing the cross-sections for each reaction at a desired energy, and outputs a list of the potential daughter isotopes that are most likely to be generated. The program then evaluates the decay chains of these daughters to provide a list of the possible decay chains that contain the radioisotope of interest. By knowing the daughter production and decay chain for each isotope, it is possible to go from the desired radioisotope to the stable isotope that can be used as a target for its production. This project would facilitate the search for new pathways to creating useful theranostic isotopes.
	Slides TUXD3 [0.591 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUXD3
About •	Received ※ 17 July 2022 — Revised ※ 01 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 25 August 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPA09	Designing Accelerator-Driven Experiments for Accelerator-Driven Reactors	target, experiment, site, operation	360
	M.A. Cummings, R.J. Abrams, R.P. Johnson, J.D. Lobo, T.J. Roberts Muons, Inc, Illinois, USA
	Muons, Inc., with its collaborators, to the best of our knowledge is the only one of the several reactor concept companies in the US that is concentrating on an accelerator-driven subcritical high-power reactor design. The major objection to such systems has been that short interruptions of beam of even a few seconds would turn off fission power long enough to induce temperature-gradient shocks and subsequent fatigue of solid fuel elements. MuSTAR solves this problem by using a molten-salt fuel. MuSTAR is a reactor design that not only includes a particle accelerator as an integral part, but has several innovative features that make it a compelling solution to many problems. We note that the ADSR concepts being pursued by the Chinese Academy of Science (ADANES) and the Belgians (MYRRHA) are based on traditional solid fuel elements and require exceptional stability from their accelerator.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA09
About •	Received ※ 03 August 2022 — Revised ※ 05 August 2022 — Accepted ※ 08 August 2022 — Issue date ※ 29 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPA58	Iterative Tuning of the Beam Feedforward Controller for LANSCE LINAC Digital Low Level RF Control System	controls, beam-loading, cavity, LLRF	475
	S. Kwon, A.T. Archuleta, L.J. Castellano, M.S. Prokop, C. Rose, P.A. Torrez, P. Van Rooy LANL, Los Alamos, New Mexico, USA
	Funding: USDOE This paper addresses an iterative particle beam phase and amplitude feedforward controller tuning method based on the gradient search approach. The method does not need an a priori plant model as it only needs data collected in previous experimental runs. The controller is implemented on a field programmable gate array (FPGA) equipped with a real-time operating system and a network connection. Data from each RF pulse is collected and sent via the network to the FPGA for processing. The controller tuning is performed between the RF pulses. Once the tuning is performed, the controller parameters are downloaded to the controller in the FPGA and new controller parameters are applied at the upcoming RF pulse
	Poster TUPA58 [0.998 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA58
About •	Received ※ 01 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 07 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPA69	Improving Cavity Phase Measurements at Los Alamos Neutron Science Center	cavity, GUI, LLRF, controls	493
	P. Van Rooy, A.T. Archuleta, L.J. Castellano, S. Kwon, M.S. Prokop, P.A. Torrez LANL, Los Alamos, New Mexico, USA
	Control stability of the phase and amplitude in the cavity is a significant contributor to beam performance. The ability to measure phase and amplitude of pulsed RF systems at accuracies of ± 0.1 degrees and ± 0.1 percent required for our systems is difficult, and custom-designed circuitry is required. The digital low-level RF upgrade at the Los Alamos Neutron Science Center is continuing to progress with improved cavity phase measurements. The previous generation of the cavity phase and amplitude measurement system has a phase ambiguity, which requires repeated calibrations to ascertain the correct phase direction. The new phase measurement system removes the ambiguity and the need for field calibration while improving the range and precision of the cavity phase measurements. In addition, the new digital low-level RF systems is designed to upgrade the legacy system without significant mechanical, electrical, or cabling changes. Performance data for the new phase measurement system is presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA69
About •	Received ※ 02 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 21 August 2022 — Issue date ※ 08 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPA25	Field Emission Mitigation in CEBAF SRF Cavities Using Deep Learning	cavity, radiation, detector, linac	676
	K. Ahammed, J. Li ODU, Norfolk, Virginia, USA A. Carpenter, R. Suleiman, C. Tennant, L.S. Vidyaratne JLab, Newport News, Virginia, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. The Continuous Electron Beam Accelerator Facility (CEBAF) operates hundreds of superconducting radio frequency (SRF) cavities in its two main linear accelerators. Field emission can occur when the cavities are set to high operating RF gradients and is an ongoing operational challenge. This is especially true in newer, higher gradient SRF cavities. Field emission results in damage to accelerator hardware, generates high levels of neutron and gamma radiation, and has deleterious effects on CEBAF operations. So, field emission reduction is imperative for the reliable, high gradient operation of CEBAF that is required by experimenters. Here we explore the use of deep learning architectures via multilayer perceptron to simultaneously model radiation measurements at multiple detectors in response to arbitrary gradient distributions. These models are trained on collected data and could be used to minimize the radiation production through gradient redistribution. This work builds on previous efforts in developing machine learning (ML) models, and is able to produce similar model performance as our previous ML model without requiring knowledge of the field emission onset for each cavity.
	Poster WEPA25 [1.586 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA25
About •	Received ※ 01 August 2022 — Revised ※ 03 August 2022 — Accepted ※ 05 August 2022 — Issue date ※ 20 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPA32	Spallation Neutron Source Cryogenic Moderator System Helium Gas Analysis System	cryogenics, MMI, operation, target	699
	B. DeGraff, L. Pinion ORNL RAD, Oak Ridge, Tennessee, USA R. Armstrong, J. Denison, M.P. Howell, S.-H. Kim, D. Montierth ORNL, Oak Ridge, Tennessee, USA M.D. Williamson LBNL, Berkeley, California, USA
	Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) operates the Cryogenic Moderator System (CMS). The CMS comprises a 20-K helium refrigerator and three helium to hydrogen heat exchangers in support of hydrogen cooled spallation moderation vessels. This system uses vessels filled with activated carbon as the final major component to remove oil vapor from the compressed helium in the cryogenic cold box. SNS uses a LINDE multi-component gas analyzer to detect the presence of contaminants in the warm helium flow upstream of the cold box including aerosolized oil vapor. The design challenges of installing and operating this analyzer on the CMS system due to normal system operating pressures will be discussed. The design, fabrication, installation, commissioning, and initial results of this system operation will be presented. Future upgrades to the analyzer system will also be discussed.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA32
About •	Received ※ 06 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 05 October 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPA37	Benchmarking and Exploring Parameter Space of the 2-Phase Bubble Tracking Model for Liquid Mercury Target Simulation	target, simulation, experiment, injection	711
	L. Lin, M.I. Radaideh, H. Tran, D.E. Winder ORNL, Oak Ridge, Tennessee, USA
	Funding: This project was funded by the U.S. DOE under grant DE-SC0009915. High intensity proton pulses strike the Spallation Neutron Source (SNS)’s mercury target to provide bright neutron beams. These strikes deposit extensive energy into the mercury and its steel vessel. Prediction of the resultant loading on the target is difficult when helium gas is intentionally injected into the mercury to reduce the loading and to mitigate the pitting damage on the vessel. A 2-phase material model that incorporates the Rayleigh-Plesset (R-P) model is expected to address this complex multi-physics dynamics problem by including the bubble dynamics in the liquid mercury. We present a study comparing the measured target strains in the SNS target station with the simulation results of the solid mechanics simulation framework. We investigate a wide range of various physical model parameters, including the number of bubble families, bubble size distribution, viscosity, surface tension, etc. to understand their impact on simulation accuracy. Our initial findings reveal that using 8-10 bubble families in the model renders a simulation strain envelope that covers the experimental ones. Further optimization studies are planned to predict the strain response more accurately.
	Poster WEPA37 [1.985 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA37
About •	Received ※ 27 July 2022 — Revised ※ 08 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 01 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRXD3	Measurements of the Five-Dimensional Phase Space Distribution of an Intense Ion Beam	simulation, emittance, rfq, quadrupole	910
	A.M. Hoover, A.V. Aleksandrov, S.M. Cousineau, K.J. Ruisard, A.P. Zhukov ORNL, Oak Ridge, Tennessee, USA
	Funding: Supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics; authored by UT- Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. No simulation of intense beam transport has accurately reproduced measurements at the level of beam halo. One potential explanation of this discrepancy is a lack of knowledge of the initial distribution of particles in six-dimensional (6D) phase space. A direct 6D measurement of an ion beam was recently performed at the Spallation Neutron Source (SNS) Beam Test Facility (BTF), revealing nonlinear transverse-longitudinal correlations in the beam core that affect downstream evolution. Unfortunately, direct 6D measurements are limited in resolution and dynamic range; here, we discuss the use of three slits and one screen to measure a 5D projection of the 6D phase space distribution, overcoming these limitations at the cost of one dimension. We examine the measured 5D distribution before and after transport through the BTF and compare to particle-in-cell simulations. We also discuss the possibility of reconstructing the 6D distribution from 5D and 4D projections.
	Slides FRXD3 [4.078 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-FRXD3
About •	Received ※ 03 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 02 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOODE1

Applications of Particle Accelerators

linac, electron, site, target

1

M. Uesaka
JAEC, Tokyo, Japan

Applications of particle accelerators amid global policies of carbon neutrality and economic security. are reviewed. Downsizing of high energy large scaled accelerators by advanced technologies enables a variety of medical and industrial uses. One of the highlights is upgrade of sustainable supply chain of medical radioisotopes by the best mix of research reactors and accelerators. 99Mo/99mTc for diagnosis are going to be produced by low enriched U reactor and proton-cyclotron, electron rhodotron and electron linac. Moreover, the theranostics by 177Lu (beta) and 211At/225Ac (alpha) are going to be realized. Proton-cyclotron and electron linac are expected to produce them soon. This new affordable radiation therapy should play an important role in the IAEA project of Rays of Hopes. Next, proof-of-principle trails of on-site bridge inspection of the portable X-band (9.3 GHz) electron linac X-ray/neutron sources are under way. The technical guideline for the practical inspection is to be formed in a couple of years. Ultimate micro-accelerator for microbeam applications is dielectric laser accelerator, such as ACHIP project. Updated projects and results are also introduced.

Slides MOODE1 [3.065 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOODE1

About •

Received ※ 02 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 11 August 2022

Cite •

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

MOPA02

Activation of the IBA Proteus One Proton Therapy Beamline Using BDSIM and FISPACT-II

proton, shielding, radiation, simulation

59

E. Ramoisiaux, E. Gnacadja, C. Hernalsteens, N. Pauly, R. Tesse, M. Vanwelde
ULB, Bruxelles, Belgium
C. Hernalsteens
CERN, Meyrin, Switzerland

Cyclotron-based proton therapy systems generate large fluxes of secondary particles due to the beam interactions with the beamline elements, with the energy degrader being the dominant source. Compact systems exacerbate these challenges for concrete shielding and beamline element activation. Our implementation of the Rigorous Two-Step method uses Beam Delivery Simulation (BDSIM), a Geant4-based particle tracking code, for primary and secondary particles transport and fluence scoring, and FISPACT-II for time-dependent nuclear inventory and solving the rate equations. This approach is applied to the Ion Beam Applications (IBA) Proteus®ONE (P1) system, for which a complete model has been built, validated, and used for shielding activation simulations. We detail the first simulations of the activation on quadrupole magnets in high-fluence locations downstream of the degrader. Results show the evolution of the long-lived nuclide concentrations for short and long timescales throughout the facility lifetime for a typical operation scenario.

Poster MOPA02 [0.553 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA02

About •

Received ※ 02 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 19 August 2022 — Issue date ※ 21 September 2022

Cite •

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

TUXD3

Production Pathways for Medically Interesting Isotopes

target, radiation, proton, isotope-production

271

L. Rosado Del Rio
University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico
L.F. Dabill
Coe College, Cedar Rapids, Iowa, USA
A. Hutton
JLab, Newport News, Virginia, USA

Funding: LR was supported by the U.S. NSF REU at Old Dominion University Grant No. 1950141. AH was supported by the U.S. DOE, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177
Radioisotopes are commonly used in nuclear medicine for treating cancer and new, more effective treatment options are always desired. As a result, there is a national need for new radioisotopes and ways to produce them. A computer program was created that evaluates the daughters for all known reactions of projectiles (gamma rays, protons or neutrons) with every stable target isotope by comparing the cross-sections for each reaction at a desired energy, and outputs a list of the potential daughter isotopes that are most likely to be generated. The program then evaluates the decay chains of these daughters to provide a list of the possible decay chains that contain the radioisotope of interest. By knowing the daughter production and decay chain for each isotope, it is possible to go from the desired radioisotope to the stable isotope that can be used as a target for its production. This project would facilitate the search for new pathways to creating useful theranostic isotopes.

Slides TUXD3 [0.591 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUXD3

About •

Received ※ 17 July 2022 — Revised ※ 01 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 25 August 2022

Cite •

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

TUPA09

Designing Accelerator-Driven Experiments for Accelerator-Driven Reactors

target, experiment, site, operation

360

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

Muons, Inc., with its collaborators, to the best of our knowledge is the only one of the several reactor concept companies in the US that is concentrating on an accelerator-driven subcritical high-power reactor design. The major objection to such systems has been that short interruptions of beam of even a few seconds would turn off fission power long enough to induce temperature-gradient shocks and subsequent fatigue of solid fuel elements. Mu*STAR solves this problem by using a molten-salt fuel. Mu*STAR is a reactor design that not only includes a particle accelerator as an integral part, but has several innovative features that make it a compelling solution to many problems. We note that the ADSR concepts being pursued by the Chinese Academy of Science (ADANES) and the Belgians (MYRRHA) are based on traditional solid fuel elements and require exceptional stability from their accelerator.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA09

About •

Received ※ 03 August 2022 — Revised ※ 05 August 2022 — Accepted ※ 08 August 2022 — Issue date ※ 29 September 2022

Cite •

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

TUPA58

Iterative Tuning of the Beam Feedforward Controller for LANSCE LINAC Digital Low Level RF Control System

controls, beam-loading, cavity, LLRF

475

S. Kwon, A.T. Archuleta, L.J. Castellano, M.S. Prokop, C. Rose, P.A. Torrez, P. Van Rooy
LANL, Los Alamos, New Mexico, USA

Funding: USDOE
This paper addresses an iterative particle beam phase and amplitude feedforward controller tuning method based on the gradient search approach. The method does not need an a priori plant model as it only needs data collected in previous experimental runs. The controller is implemented on a field programmable gate array (FPGA) equipped with a real-time operating system and a network connection. Data from each RF pulse is collected and sent via the network to the FPGA for processing. The controller tuning is performed between the RF pulses. Once the tuning is performed, the controller parameters are downloaded to the controller in the FPGA and new controller parameters are applied at the upcoming RF pulse

Poster TUPA58 [0.998 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA58

About •

Received ※ 01 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 07 September 2022

Cite •

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

TUPA69

Improving Cavity Phase Measurements at Los Alamos Neutron Science Center

cavity, GUI, LLRF, controls

493

P. Van Rooy, A.T. Archuleta, L.J. Castellano, S. Kwon, M.S. Prokop, P.A. Torrez
LANL, Los Alamos, New Mexico, USA

Control stability of the phase and amplitude in the cavity is a significant contributor to beam performance. The ability to measure phase and amplitude of pulsed RF systems at accuracies of ± 0.1 degrees and ± 0.1 percent required for our systems is difficult, and custom-designed circuitry is required. The digital low-level RF upgrade at the Los Alamos Neutron Science Center is continuing to progress with improved cavity phase measurements. The previous generation of the cavity phase and amplitude measurement system has a phase ambiguity, which requires repeated calibrations to ascertain the correct phase direction. The new phase measurement system removes the ambiguity and the need for field calibration while improving the range and precision of the cavity phase measurements. In addition, the new digital low-level RF systems is designed to upgrade the legacy system without significant mechanical, electrical, or cabling changes. Performance data for the new phase measurement system is presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA69

About •

Received ※ 02 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 21 August 2022 — Issue date ※ 08 September 2022

Cite •

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

WEPA25

Field Emission Mitigation in CEBAF SRF Cavities Using Deep Learning

cavity, radiation, detector, linac

676

K. Ahammed, J. Li
ODU, Norfolk, Virginia, USA
A. Carpenter, R. Suleiman, C. Tennant, L.S. Vidyaratne
JLab, Newport News, Virginia, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
The Continuous Electron Beam Accelerator Facility (CEBAF) operates hundreds of superconducting radio frequency (SRF) cavities in its two main linear accelerators. Field emission can occur when the cavities are set to high operating RF gradients and is an ongoing operational challenge. This is especially true in newer, higher gradient SRF cavities. Field emission results in damage to accelerator hardware, generates high levels of neutron and gamma radiation, and has deleterious effects on CEBAF operations. So, field emission reduction is imperative for the reliable, high gradient operation of CEBAF that is required by experimenters. Here we explore the use of deep learning architectures via multilayer perceptron to simultaneously model radiation measurements at multiple detectors in response to arbitrary gradient distributions. These models are trained on collected data and could be used to minimize the radiation production through gradient redistribution. This work builds on previous efforts in developing machine learning (ML) models, and is able to produce similar model performance as our previous ML model without requiring knowledge of the field emission onset for each cavity.

Poster WEPA25 [1.586 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA25

About •

Received ※ 01 August 2022 — Revised ※ 03 August 2022 — Accepted ※ 05 August 2022 — Issue date ※ 20 September 2022

Cite •

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

WEPA32

Spallation Neutron Source Cryogenic Moderator System Helium Gas Analysis System

cryogenics, MMI, operation, target

699

B. DeGraff, L. Pinion
ORNL RAD, Oak Ridge, Tennessee, USA
R. Armstrong, J. Denison, M.P. Howell, S.-H. Kim, D. Montierth
ORNL, Oak Ridge, Tennessee, USA
M.D. Williamson
LBNL, Berkeley, California, USA

Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) operates the Cryogenic Moderator System (CMS). The CMS comprises a 20-K helium refrigerator and three helium to hydrogen heat exchangers in support of hydrogen cooled spallation moderation vessels. This system uses vessels filled with activated carbon as the final major component to remove oil vapor from the compressed helium in the cryogenic cold box. SNS uses a LINDE multi-component gas analyzer to detect the presence of contaminants in the warm helium flow upstream of the cold box including aerosolized oil vapor. The design challenges of installing and operating this analyzer on the CMS system due to normal system operating pressures will be discussed. The design, fabrication, installation, commissioning, and initial results of this system operation will be presented. Future upgrades to the analyzer system will also be discussed.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA32

About •

Received ※ 06 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 05 October 2022

Cite •

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

WEPA37

Benchmarking and Exploring Parameter Space of the 2-Phase Bubble Tracking Model for Liquid Mercury Target Simulation

target, simulation, experiment, injection

711

L. Lin, M.I. Radaideh, H. Tran, D.E. Winder
ORNL, Oak Ridge, Tennessee, USA

Funding: This project was funded by the U.S. DOE under grant DE-SC0009915.
High intensity proton pulses strike the Spallation Neutron Source (SNS)’s mercury target to provide bright neutron beams. These strikes deposit extensive energy into the mercury and its steel vessel. Prediction of the resultant loading on the target is difficult when helium gas is intentionally injected into the mercury to reduce the loading and to mitigate the pitting damage on the vessel. A 2-phase material model that incorporates the Rayleigh-Plesset (R-P) model is expected to address this complex multi-physics dynamics problem by including the bubble dynamics in the liquid mercury. We present a study comparing the measured target strains in the SNS target station with the simulation results of the solid mechanics simulation framework. We investigate a wide range of various physical model parameters, including the number of bubble families, bubble size distribution, viscosity, surface tension, etc. to understand their impact on simulation accuracy. Our initial findings reveal that using 8-10 bubble families in the model renders a simulation strain envelope that covers the experimental ones. Further optimization studies are planned to predict the strain response more accurately.

Poster WEPA37 [1.985 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA37

About •

Received ※ 27 July 2022 — Revised ※ 08 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 01 September 2022

Cite •

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

FRXD3

Measurements of the Five-Dimensional Phase Space Distribution of an Intense Ion Beam

simulation, emittance, rfq, quadrupole

910

A.M. Hoover, A.V. Aleksandrov, S.M. Cousineau, K.J. Ruisard, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA

Funding: Supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics; authored by UT- Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
No simulation of intense beam transport has accurately reproduced measurements at the level of beam halo. One potential explanation of this discrepancy is a lack of knowledge of the initial distribution of particles in six-dimensional (6D) phase space. A direct 6D measurement of an ion beam was recently performed at the Spallation Neutron Source (SNS) Beam Test Facility (BTF), revealing nonlinear transverse-longitudinal correlations in the beam core that affect downstream evolution. Unfortunately, direct 6D measurements are limited in resolution and dynamic range; here, we discuss the use of three slits and one screen to measure a 5D projection of the 6D phase space distribution, overcoming these limitations at the cost of one dimension. We examine the measured 5D distribution before and after transport through the BTF and compare to particle-in-cell simulations. We also discuss the possibility of reconstructing the 6D distribution from 5D and 4D projections.

Slides FRXD3 [4.078 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-FRXD3

About •

Received ※ 03 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 02 September 2022

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