NAPAC2019 - List of Keywords (space-charge)

Paper	Title	Other Keywords	Page
TUZBB4	Space Charge Study of the Jefferson Lab Magnetized Electron Beam	laser, electron, cathode, gun	360
	S.A.K. Wijethunga, J.R. Delayen, G.A. Krafft ODU, Norfolk, Virginia, USA J.F. Benesch, F.E. Hannon, C. Hernandez-Garcia, G.A. Krafft, M.A. Mamun, M. Poelker, R. Suleiman, S. Zhang JLab, Newport News, Virginia, USA
	Magnetized electron cooling could result in high luminosity at the proposed Jefferson Lab Electron-Ion Collider (JLEIC). In order to increase the cooling efficiency, a bunched electron beam with high bunch charge and high repetition rate is required. We generated magnetized electron beams with high bunch charge using a new compact DC high voltage photo-gun biased at -300 kV with alkali-antimonide photocathode and a commercial ultrafast laser. This contribution explores how magnetization affects space charge dominated beams as a function of magnetic field strength, gun high voltage, laser pulse width, and laser spot size.
	Slides TUZBB4 [12.582 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBB4
About •	paper received ※ 28 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLM01	Experimental Studies of Resonance Structure Dynamics With Space Charge	resonance, experiment, simulation, quadrupole	372
	L. Dovlatyan, T.M. Antonsen, B.L. Beaudoin, S. Bernal, I. Haber, D.F. Sutter, G.D. Wyche UMD, College Park, Maryland, USA
	Funding: Funding for this project is provided by DOE-HEP award #DE-SC0010301 Space charge is one of the fundamental limitations for next generation high intensity circular accelerators. It can lead to halo growth as well as beam loss, and affect resonance structure in ways not completely understood. We employ the University of Maryland Electron Ring (UMER), a circular 10 keV storage machine, to experimentally study the structure of betatron resonances for beams of varying degrees of space charge intensity. Experimental techniques such as tune scans and frequency maps are employed. Results are also compared to computer simulations using the WARP code.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM01
About •	paper received ※ 26 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLM12	Method for a Multiple Square Well Model to Study Transverse Mode Coupling Instability	DTL, collective-effects, longitudinal-dynamics, simulation	395
	M.A. Balcewicz, Y. Hao FRIB, East Lansing, Michigan, USA M. Blaskiewicz BNL, Upton, New York, USA
	In the high intensity limit it can become difficult to simulate intense beams sufficiently within a short time scale due to collective effects. Semi-Analytic methods such as the Square Well Model/AirBag Square Well* (SWM/ABS) exist to estimate collective effects within a short time scale. SWM/ABS discretizes the longitudinal confining potential into a single square well enforcing linearity for the case of linear transverse optics. A method is proposed here to extend the Square Well Method multiple square wells. This method preserves linearity properties that make it easily solvable within a short time scale as well as including nonlinear effects from the longitudinal potential shape. M. Blaskiewicz PRSTAB 1, 044201. 1998 *A. Burov PRAB 22, 034202. 2019
	Poster TUPLM12 [1.818 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM12
About •	paper received ※ 27 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLM22	Off Axis Dependence of Current Dependent Coherent Tune Shifts in the UMER Ring	experiment, electron, dipole, storage-ring	422
	D.F. Sutter, B.L. Beaudoin, L. Dovlatyan UMD, College Park, Maryland, USA
	Funding: Work supported by U. S. Department of Energy grant number DESC00010301 The University of Maryland Electron Ring (UMER) was built to explore space charge effects in the extreme - beyond the space charge limit of most existing storage rings. At the nominal operating kinetic energy of 10 keV, the beam is also non relativistic. We have experimentally verified that the current dependent coherent tune shift obeys the Laslett formula over a wide current range for a cylindrical geometry and non penetrating magnetic fields when the beam is on axis; i.e. the average closed orbit displacement around the ring is essentially zero.* In the current experiment this measurement is extended to the change in current dependent coherent tune shift as the average closed orbit is moved off axis. It can be displaced over approximately ±10 mm of the vacuum pipe diameter of 50 mm without loss of beam. Because the 36 bending magnets in UMER are very short, we treat each of them as a local kick and then increment each by a calculated small amount to achieve the desired, global closed orbit displacement. Experimental results are compared to predictions by Zotter and others. * D. für Sutter, M.Cornacchia, et al, "Current dependent tune shifts in the University of Maryland electron ring", NAPAC 2013.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM22
About •	paper received ※ 29 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019
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WEPLS10	Modeling of Space-Charge Effects in the ORISS MRTOF Device for Applications to FRIB	focusing, optics, operation, linac	786
	R. Hipple MSU, East Lansing, Michigan, USA S.M. Lund FRIB, East Lansing, Michigan, USA
	The Oak Ridge Isotope/Isomer Spectrometer and Separator (ORISS) is an electrostatic multiply reflecting time-of-flight (MRTOF) mass separator constructed by the University Radioactive Ion Beam Consortium (UNIRIB) and Louisiana State University. The device was never fully commissioned, and was eventually shipped to Michigan State University for use at the Facility for Rare Isotopes and Beams (FRIB). The separation process is sensitive to space-charge effects due to the reflection of ions at both ends of the trap, as well as nonlinearities in the optics. In this study we apply the time-based particle-in-cell code Warp to model the effects of intense space-charge during the separation process. We find that the optics can be tuned for isochronous operation and focusing in the presence of intense space-charge to enable separation of bunches with high particle counts. This suggests the device may be effectively utilized at FRIB as a separator, spectrograph and spectrometer.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS10
About •	paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLE10	Simulating Space Charge Dominated Beam Dynamics Using FMM	simulation, emittance, cathode, multipole	909
	S.A. Schmid, H. De Gersem, E. Gjonaj TEMF, TU Darmstadt, Darmstadt, Germany M. Dohlus DESY, Hamburg, Germany
	Funding: This work is supported by the DFG in the framework of GRK 2128. In this contribution, we simulate the beam generation in the high brilliance photoinjector of the European XFEL developed at DESY-PITZ. The investigation addresses the influence of space charge on the emittance of bunches with up to 1.0 nC bunch charge. For the simulations, we implemented a mesh-less fast multipole method (FMM) in the 3D tracking code REPTIL. We present numerical convergence and performance studies as well as a validation with commonly used simulation tools ASTRA and KRACK3. Furthermore, we provide a machine parameter study to minimize the beam emittance in the injector.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLE10
About •	paper received ※ 27 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THZBB3	Novel Emittance Measurement Combining Foil Focusing and Pepper-Pot Techniques	focusing, emittance, electron, experiment	961
	K.A. Schultz, G.T. Ortiz, M.E. Schulze LANL, Los Alamos, New Mexico, USA C. Carlson, D. Guerrero NSTec, Los Alamos, New Mexico, USA
	Funding: Work supported by the US National Nuclear Security Agency and the US Department of Energy under contract DE-AC52-06NA25396. In this paper, we describe a direct measurement of foil focusing of an intense, relativistic electron beam com-bined with the pepper-pot technique to perform emit-tance measurements. Foil focusing occurs when a thin, grounded, conducting foil shorts out the radial electric field of a transiting electron beam, causing its self-magnetic field to focus the beam. A 40-ns pulse was extracted from the main pulse of the 16-MeV, 1.65 kA beam from Axis-II of the Dual Axis Radiographic Hy-drodynamic Test Facility to perform the measurements. We show that not accounting for foil focusing signifi-cantly reduces the measured emittance.
	Slides THZBB3 [5.382 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB3
About •	paper received ※ 27 August 2019 paper accepted ※ 15 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

TUZBB4

Space Charge Study of the Jefferson Lab Magnetized Electron Beam

laser, electron, cathode, gun

360

S.A.K. Wijethunga, J.R. Delayen, G.A. Krafft
ODU, Norfolk, Virginia, USA
J.F. Benesch, F.E. Hannon, C. Hernandez-Garcia, G.A. Krafft, M.A. Mamun, M. Poelker, R. Suleiman, S. Zhang
JLab, Newport News, Virginia, USA

Magnetized electron cooling could result in high luminosity at the proposed Jefferson Lab Electron-Ion Collider (JLEIC). In order to increase the cooling efficiency, a bunched electron beam with high bunch charge and high repetition rate is required. We generated magnetized electron beams with high bunch charge using a new compact DC high voltage photo-gun biased at -300 kV with alkali-antimonide photocathode and a commercial ultrafast laser. This contribution explores how magnetization affects space charge dominated beams as a function of magnetic field strength, gun high voltage, laser pulse width, and laser spot size.

Slides TUZBB4 [12.582 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBB4

About •

paper received ※ 28 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019

Export •

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

TUPLM01

Experimental Studies of Resonance Structure Dynamics With Space Charge

resonance, experiment, simulation, quadrupole

372

L. Dovlatyan, T.M. Antonsen, B.L. Beaudoin, S. Bernal, I. Haber, D.F. Sutter, G.D. Wyche
UMD, College Park, Maryland, USA

Funding: Funding for this project is provided by DOE-HEP award #DE-SC0010301
Space charge is one of the fundamental limitations for next generation high intensity circular accelerators. It can lead to halo growth as well as beam loss, and affect resonance structure in ways not completely understood. We employ the University of Maryland Electron Ring (UMER), a circular 10 keV storage machine, to experimentally study the structure of betatron resonances for beams of varying degrees of space charge intensity. Experimental techniques such as tune scans and frequency maps are employed. Results are also compared to computer simulations using the WARP code.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM01

About •

paper received ※ 26 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLM12

Method for a Multiple Square Well Model to Study Transverse Mode Coupling Instability

DTL, collective-effects, longitudinal-dynamics, simulation

395

M.A. Balcewicz, Y. Hao
FRIB, East Lansing, Michigan, USA
M. Blaskiewicz
BNL, Upton, New York, USA

In the high intensity limit it can become difficult to simulate intense beams sufficiently within a short time scale due to collective effects. Semi-Analytic methods such as the Square Well Model*/AirBag Square Well** (SWM/ABS) exist to estimate collective effects within a short time scale. SWM/ABS discretizes the longitudinal confining potential into a single square well enforcing linearity for the case of linear transverse optics. A method is proposed here to extend the Square Well Method multiple square wells. This method preserves linearity properties that make it easily solvable within a short time scale as well as including nonlinear effects from the longitudinal potential shape.
*M. Blaskiewicz PRSTAB 1, 044201. 1998
**A. Burov PRAB 22, 034202. 2019

Poster TUPLM12 [1.818 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM12

About •

paper received ※ 27 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLM22

Off Axis Dependence of Current Dependent Coherent Tune Shifts in the UMER Ring

experiment, electron, dipole, storage-ring

422

D.F. Sutter, B.L. Beaudoin, L. Dovlatyan
UMD, College Park, Maryland, USA

Funding: Work supported by U. S. Department of Energy grant number DESC00010301
The University of Maryland Electron Ring (UMER) was built to explore space charge effects in the extreme - beyond the space charge limit of most existing storage rings. At the nominal operating kinetic energy of 10 keV, the beam is also non relativistic. We have experimentally verified that the current dependent coherent tune shift obeys the Laslett formula over a wide current range for a cylindrical geometry and non penetrating magnetic fields when the beam is on axis; i.e. the average closed orbit displacement around the ring is essentially zero.* In the current experiment this measurement is extended to the change in current dependent coherent tune shift as the average closed orbit is moved off axis. It can be displaced over approximately ±10 mm of the vacuum pipe diameter of 50 mm without loss of beam. Because the 36 bending magnets in UMER are very short, we treat each of them as a local kick and then increment each by a calculated small amount to achieve the desired, global closed orbit displacement. Experimental results are compared to predictions by Zotter and others.
* D. für Sutter, M.Cornacchia, et al, "Current dependent tune shifts in the University of Maryland electron ring", NAPAC 2013.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM22

About •

paper received ※ 29 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019

Export •

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

WEPLS10

Modeling of Space-Charge Effects in the ORISS MRTOF Device for Applications to FRIB

focusing, optics, operation, linac

786

R. Hipple
MSU, East Lansing, Michigan, USA
S.M. Lund
FRIB, East Lansing, Michigan, USA

The Oak Ridge Isotope/Isomer Spectrometer and Separator (ORISS) is an electrostatic multiply reflecting time-of-flight (MRTOF) mass separator constructed by the University Radioactive Ion Beam Consortium (UNIRIB) and Louisiana State University. The device was never fully commissioned, and was eventually shipped to Michigan State University for use at the Facility for Rare Isotopes and Beams (FRIB). The separation process is sensitive to space-charge effects due to the reflection of ions at both ends of the trap, as well as nonlinearities in the optics. In this study we apply the time-based particle-in-cell code Warp to model the effects of intense space-charge during the separation process. We find that the optics can be tuned for isochronous operation and focusing in the presence of intense space-charge to enable separation of bunches with high particle counts. This suggests the device may be effectively utilized at FRIB as a separator, spectrograph and spectrometer.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS10

About •

paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

WEPLE10

Simulating Space Charge Dominated Beam Dynamics Using FMM

simulation, emittance, cathode, multipole

909

S.A. Schmid, H. De Gersem, E. Gjonaj
TEMF, TU Darmstadt, Darmstadt, Germany
M. Dohlus
DESY, Hamburg, Germany

Funding: This work is supported by the DFG in the framework of GRK 2128.
In this contribution, we simulate the beam generation in the high brilliance photoinjector of the European XFEL developed at DESY-PITZ. The investigation addresses the influence of space charge on the emittance of bunches with up to 1.0 nC bunch charge. For the simulations, we implemented a mesh-less fast multipole method (FMM) in the 3D tracking code REPTIL. We present numerical convergence and performance studies as well as a validation with commonly used simulation tools ASTRA and KRACK3. Furthermore, we provide a machine parameter study to minimize the beam emittance in the injector.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLE10

About •

paper received ※ 27 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019

Export •

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

THZBB3

Novel Emittance Measurement Combining Foil Focusing and Pepper-Pot Techniques

focusing, emittance, electron, experiment

961

K.A. Schultz, G.T. Ortiz, M.E. Schulze
LANL, Los Alamos, New Mexico, USA
C. Carlson, D. Guerrero
NSTec, Los Alamos, New Mexico, USA

Funding: Work supported by the US National Nuclear Security Agency and the US Department of Energy under contract DE-AC52-06NA25396.
In this paper, we describe a direct measurement of foil focusing of an intense, relativistic electron beam com-bined with the pepper-pot technique to perform emit-tance measurements. Foil focusing occurs when a thin, grounded, conducting foil shorts out the radial electric field of a transiting electron beam, causing its self-magnetic field to focus the beam. A 40-ns pulse was extracted from the main pulse of the 16-MeV, 1.65 kA beam from Axis-II of the Dual Axis Radiographic Hy-drodynamic Test Facility to perform the measurements. We show that not accounting for foil focusing signifi-cantly reduces the measured emittance.

Slides THZBB3 [5.382 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB3

About •

paper received ※ 27 August 2019 paper accepted ※ 15 September 2019 issue date ※ 08 October 2019

Export •

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