NAPAC2019 - List of Keywords (synchrotron)

Paper	Title	Other Keywords	Page
MOPLM21	Circuit Model Analysis for High Charge in the APS Particle Accumulator Ring	impedance, injection, booster, photon	151
	K.C. Harkay, J.R. Calvey, J.C. Dooling, L. Emery, R.R. Lindberg, K.P. Wootton, C. Yao ANL, Lemont, Illinois, USA
	Funding: Work supported by U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The Advanced Photon Source (APS) particle accumulator ring (PAR) was designed to accumulate linac pulses into a single bunch with a fundamental rf system, and longitudinally compress the beam with a harmonic rf system prior to injection into the booster. For APS Upgrade, the injectors will need to supply full-current bunch replacement with high single-bunch charge for swap-out in the new storage ring. Significant bunch lengthening, energy spread, and synchrotron sidebands are observed in PAR at high charge. Lower-charge dynamics are dominated by potential well distortion, while higher-charge dynamics appear to be dominated by microwave instability. Before a numerical impedance model was available, a simple circuit model was developed by fitting the measured bunch distributions to the Haissinski equation. Energy scaling was then used to predict the beam energy sufficient to raise the instability threshold to 18-20 nC. With the beam in a linear or nearly linear regime, higher harmonic radio frequency (rf) gap voltage can be used to reduce the bunch length at high charge and better match the booster acceptance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLM21
About •	paper received ※ 27 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)

TUPLM09	A Fast Method to Evaluate Transverse Coupled-Bunch Stability at Non-Zero Chromaticity	wakefield, dipole, betatron, simulation	387
	R.R. Lindberg ANL, Lemont, Illinois, USA
	Funding: Supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 We present a dispersion relation that gives the complex growth rate for coupled-bunch instabilities at arbitrary chromaticity in terms of its value at zero chromaticity. We compare predictions of the theory to elegant tracking simulations, and show that there are two distinct regimes to stability depending upon whether the zero chromaticity growth rate is smaller or larger than the chromatic tune shift over the bunch. We derive an approximate expression that is easily solved numerically, and furthermore indicate how the formalism can be extended to describe arbitrary longitudinal potentials.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM09
About •	paper received ※ 25 August 2019 paper accepted ※ 01 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLH09	Thermal Effects on Bragg Diffraction of XFEL Optics	FEL, photon, optics, simulation	506
	Z. Qu, J. Wu, G. Zhou SLAC, Menlo Park, California, USA Y. Ma, Z. Qu UC Merced, Merced, California, USA B. Yang Western Digital, Milpitas, California, USA
	Funding: The US Department of Energy (DOE) (DE-AC02-76SF00515); The US DOE Office of Science Early Career Research Program grant (FWP-2013-SLAC-100164). Crystal optical devices are widely used in X-ray free electron laser (XFEL) systems, monochromators, beam splitters, high-reflectance backscattering mirrors, lenses, phase plates, diffraction gratings, and spectrometers. The absorption of X-ray in these optical devices can cause increase of temperature and consequent thermal deformation, which can dynamic change in optic output. In self-seeding XFEL, the thermal deformation and strain in monochromator could cause significant seed quality degradation: central energy shift, band broadening and reduction in seed power. To quantitatively estimate the impact of thermomechanical effects on seed quality, we conduct thermomechanical simulations combined with diffraction to evaluate the seed quality with residual temperature field in a pump-probe manner. With our results, we show that a critical repetition rate could be determined, once the criteria for deviation of the seed quality are selected. This tool shows great potential for the design of XFEL optics for stable operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH09
About •	paper received ※ 28 August 2019 paper accepted ※ 13 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLE15	BPM Processor Upgrades at SPEAR3	booster, EPICS, software, controls	591
	F. Toufexis, S. Condamoor, W.J. Corbett SLAC, Menlo Park, California, USA L.W. Lai SINAP, Shanghai, People’s Republic of China P. Leban I-Tech, Solkan, Slovenia
	Funding: Work sponsored by US Department of Energy Contract DE-AC02-76SF00515. We are upgrading the BPM processors in the SPEAR3 accelerator complex as several of the existing systems have reached end of life. To reduce the resources required for maintenance we have evaluated and installed several commercial BPM processors from the SPARK series of Libera/Instrumentation Technologies. In SPEAR3 we evaluated the SPARK-ERXR turn-by-turn BPM processor as a replacement to the in-house developed/commercially built Echotek processors that are used for a range of accelerator physics studies. We show measurements of the orbit dynamics with another SPARK-ERXR in the booster synchrotron from beam injection up to ejection. We have further evaluated a Spark-EL in the transport lines to replace the in-house built uTCA-based single-pass BPM processors. In this paper we show measurements and discuss our experience with the Libera SPARK series of BPM processors and comment on the software integration.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE15
About •	paper received ※ 28 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)

WEPLS09	Fast Two-Dimensional Calculation of Coherent Synchrotron Radiation in Relativistic Beams	radiation, electron, wakefield, synchrotron-radiation	783
	J. Tang, G. Stupakov SLAC, Menlo Park, California, USA
	Coherent Synchrotron Radiation(CSR) in a relavistic beam during compression can lead to longitudinal modulation of the bunch with wavelength smaller than bunch length and is regarded as one of the main sources of emittance growth in the bunch compressor. Current simulations containing CSR wake fields often utilize one-dimensional model assuming a line beam. Despite its good computation efficiency, 1D CSR model can be inaccurate in many cases because it ignores the so-called ’compression effect’. On the other hand, the existing 3D codes are often slow and have high demands on computational resources. In this paper we propose a new method for calculation of the three-dimensional CSR wakefields in relativistic beams with integrals of retarded potentials. It generalizes the 1D model and includes the transient effects at the entrance and the exit from the magnet. Within given magnetic lattice and initial beam distributions, the formalism reduces to 2D or 3D integration along the trajectory and therefore allows fast numerical calculations using 2D or 3D matrices.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS09
About •	paper received ※ 28 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)

Paper

Title

Other Keywords

Page

MOPLM21

Circuit Model Analysis for High Charge in the APS Particle Accumulator Ring

impedance, injection, booster, photon

151

K.C. Harkay, J.R. Calvey, J.C. Dooling, L. Emery, R.R. Lindberg, K.P. Wootton, C. Yao
ANL, Lemont, Illinois, USA

Funding: Work supported by U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS) particle accumulator ring (PAR) was designed to accumulate linac pulses into a single bunch with a fundamental rf system, and longitudinally compress the beam with a harmonic rf system prior to injection into the booster. For APS Upgrade, the injectors will need to supply full-current bunch replacement with high single-bunch charge for swap-out in the new storage ring. Significant bunch lengthening, energy spread, and synchrotron sidebands are observed in PAR at high charge. Lower-charge dynamics are dominated by potential well distortion, while higher-charge dynamics appear to be dominated by microwave instability. Before a numerical impedance model was available, a simple circuit model was developed by fitting the measured bunch distributions to the Haissinski equation. Energy scaling was then used to predict the beam energy sufficient to raise the instability threshold to 18-20 nC. With the beam in a linear or nearly linear regime, higher harmonic radio frequency (rf) gap voltage can be used to reduce the bunch length at high charge and better match the booster acceptance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLM21

About •

paper received ※ 27 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)

TUPLM09

A Fast Method to Evaluate Transverse Coupled-Bunch Stability at Non-Zero Chromaticity

wakefield, dipole, betatron, simulation

387

R.R. Lindberg
ANL, Lemont, Illinois, USA

Funding: Supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
We present a dispersion relation that gives the complex growth rate for coupled-bunch instabilities at arbitrary chromaticity in terms of its value at zero chromaticity. We compare predictions of the theory to elegant tracking simulations, and show that there are two distinct regimes to stability depending upon whether the zero chromaticity growth rate is smaller or larger than the chromatic tune shift over the bunch. We derive an approximate expression that is easily solved numerically, and furthermore indicate how the formalism can be extended to describe arbitrary longitudinal potentials.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM09

About •

paper received ※ 25 August 2019 paper accepted ※ 01 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLH09

Thermal Effects on Bragg Diffraction of XFEL Optics

FEL, photon, optics, simulation

506

Z. Qu, J. Wu, G. Zhou
SLAC, Menlo Park, California, USA
Y. Ma, Z. Qu
UC Merced, Merced, California, USA
B. Yang
Western Digital, Milpitas, California, USA

Funding: The US Department of Energy (DOE) (DE-AC02-76SF00515); The US DOE Office of Science Early Career Research Program grant (FWP-2013-SLAC-100164).
Crystal optical devices are widely used in X-ray free electron laser (XFEL) systems, monochromators, beam splitters, high-reflectance backscattering mirrors, lenses, phase plates, diffraction gratings, and spectrometers. The absorption of X-ray in these optical devices can cause increase of temperature and consequent thermal deformation, which can dynamic change in optic output. In self-seeding XFEL, the thermal deformation and strain in monochromator could cause significant seed quality degradation: central energy shift, band broadening and reduction in seed power. To quantitatively estimate the impact of thermomechanical effects on seed quality, we conduct thermomechanical simulations combined with diffraction to evaluate the seed quality with residual temperature field in a pump-probe manner. With our results, we show that a critical repetition rate could be determined, once the criteria for deviation of the seed quality are selected. This tool shows great potential for the design of XFEL optics for stable operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH09

About •

paper received ※ 28 August 2019 paper accepted ※ 13 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLE15

BPM Processor Upgrades at SPEAR3

booster, EPICS, software, controls

591

F. Toufexis, S. Condamoor, W.J. Corbett
SLAC, Menlo Park, California, USA
L.W. Lai
SINAP, Shanghai, People’s Republic of China
P. Leban
I-Tech, Solkan, Slovenia

Funding: Work sponsored by US Department of Energy Contract DE-AC02-76SF00515.
We are upgrading the BPM processors in the SPEAR3 accelerator complex as several of the existing systems have reached end of life. To reduce the resources required for maintenance we have evaluated and installed several commercial BPM processors from the SPARK series of Libera/Instrumentation Technologies. In SPEAR3 we evaluated the SPARK-ERXR turn-by-turn BPM processor as a replacement to the in-house developed/commercially built Echotek processors that are used for a range of accelerator physics studies. We show measurements of the orbit dynamics with another SPARK-ERXR in the booster synchrotron from beam injection up to ejection. We have further evaluated a Spark-EL in the transport lines to replace the in-house built uTCA-based single-pass BPM processors. In this paper we show measurements and discuss our experience with the Libera SPARK series of BPM processors and comment on the software integration.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE15

About •

paper received ※ 28 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)

WEPLS09

Fast Two-Dimensional Calculation of Coherent Synchrotron Radiation in Relativistic Beams

radiation, electron, wakefield, synchrotron-radiation

783

J. Tang, G. Stupakov
SLAC, Menlo Park, California, USA

Coherent Synchrotron Radiation(CSR) in a relavistic beam during compression can lead to longitudinal modulation of the bunch with wavelength smaller than bunch length and is regarded as one of the main sources of emittance growth in the bunch compressor. Current simulations containing CSR wake fields often utilize one-dimensional model assuming a line beam. Despite its good computation efficiency, 1D CSR model can be inaccurate in many cases because it ignores the so-called ’compression effect’. On the other hand, the existing 3D codes are often slow and have high demands on computational resources. In this paper we propose a new method for calculation of the three-dimensional CSR wakefields in relativistic beams with integrals of retarded potentials. It generalizes the 1D model and includes the transient effects at the entrance and the exit from the magnet. Within given magnetic lattice and initial beam distributions, the formalism reduces to 2D or 3D integration along the trajectory and therefore allows fast numerical calculations using 2D or 3D matrices.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS09

About •

paper received ※ 28 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)