IPAC2015 - List of Authors (Sajaev, V.)

Paper	Title	Page
MOPMA010	Commissioning Simulations for the APS Upgrade Lattice	553
	V. Sajaev, M. Borland ANL, Argonne, Ilinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. A hybrid seven-bend-achromat lattice has been proposed for the APS upgrade that will feature very strong focusing elements and relatively small vacuum chamber. Achieving design lattice parameters during commissioning will need to be accomplished in a short period of time to minimize dark time for APS users. We describe here start-to-end simulation of the machine commissioning beginning from first-turn trajectory correction, performing orbit and lattice correction, and finally evaluating nonlinear performance of the corrected lattice in terms of dynamic aperture and lifetime.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA010
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MOPMA011	Evaluation of Power Supply and Alignment Tolerances for the Advanced Photons Source Upgrade	556
	V. Sajaev ANL, Argonne, Ilinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The hybrid seven-bend-achromat lattice that has been proposed for the Advanced Photon Source upgrade will feature very strong focusing elements and will provide an electron beam with very low emittance. In order to be able to maintain stable operation, very tight tolerances are required for various types of errors. Here we describe evaluation of the effects of various errors including magnet power supplies, alignment, and vibration. Based on this analysis, we determine short- and long-term stability requirements
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA011
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MOPMA013	Experience with Round Beam Operation at the Advanced Photon Source	562
	A. Xiao, L. Emery, V. Sajaev, B.X. Yang ANL, Argonne, Ilinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 Very short Touschek lifetime becomes a common issue for next-generation ultra-low emittance storage ring light sources. In order to reach a longer beam lifetime, such a machine often requires operating with a vertical-to-horizontal emittance ratio close to an unity, i.e. a ‘‘round beam''. In tests at the APS storage ring, we determined how a round beam can be reached experimentally. Some general issues, such as beam injection, optics measurement and corrections, and orbit correction have been tested also. To demonstrate that a round beam was achieved, the beam size ratio is calibrated using beam lifetime measurement.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA013
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TUPJE063	Hybrid Seven-Bend-Achromat Lattice for the Advanced Photon Source Upgrade	1776
	M. Borland, V. Sajaev, Y. Sun ANL, Argonne, Ilinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. A hybrid seven-bend-achromat lattice has been designed for the APS upgrade. We describe the design goals, constraints, and methodology, including the choice of beam energy. Magnet strength and spacing is compatible with engineering designs for the magnets, diagnostics, and vacuum system. Dynamic acceptance and local momentum acceptance were simulated using realistic errors, then used to assess workable injection methods and predict beam lifetime. Predicted brightness is two to three orders of magnitude higher than the existing APS storage ring. Pointers are provided to other papers in this conference that cover subjects in more detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE063
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TUPJE064	Calibration of Fast Fiber-Optic Beam Loss Monitors for the Advanced Photon Source Storage Ring Superconducting Undulators	1780
	J.C. Dooling, K.C. Harkay, Y. Ivanyushenkov, V. Sajaev, A. Xiao ANL, Argonne, Ilinois, USA A. Vella University of Illinois at Urbana-Champaign, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357. We report on the calibration and use of fast fiber-optic (FO) beam loss monitors (BLMs) in the Advanced Photon Source storage ring (SR). A superconducting undulator prototype (SCU0) has been operating in SR Sector 6 since the beginning of CY2013, and another undulator SCU1 (a 1.1-m length undulator that is three times the length of SCU0) is scheduled for installation in Sector 1 in 2015. The SCU0 main coil often quenches during beam dumps. MARS simulations have shown that relatively small beam loss (<1 nC) can lead to temperature excursions sufficient to cause quenching when the SCU0 windings are near critical current. To characterize local beam losses, high-purity fused-silica FO cables were installed in Sector 6 next to the SCU0 cryostat and in Sector 1 where SCU1 will be installed. These BLMs aid in the search for operating modes that protect the SCU structures from beam-loss-induced quenching. In this paper, we describe the BLM calibration process that included deliberate beam dumps at locations of BLMs. We also compare beam dump events where SCU0 did and did not quench.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE064
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TUPJE066	Development of an Abort Kicker at APS to Mitigate Beam Loss-induced Quenches of the Superconducting Undulator	1787
	K.C. Harkay, J.C. Dooling, Y. Ivanyushenkov, R. Laird, F. Lenkszus, C.C. Putnam, V. Sajaev, J. Wang ANL, Argonne, Illinois, USA
	Funding: Work supported by U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The first superconducting undulator (SCU0) at the Advanced Photon Source (APS) has been delivering 80-100 keV photons for user science since January 2013. SCU0 often quenches during beam dumps triggered by the machine protection system (MPS). SCU0 typically recovers quickly after a quench, but SCU1, a second, longer device to be installed in 2015, may take longer to recover. We tested using injection kickers as an abort system to dump the beam away from SCU0 and the planned location of SCU1. An alternate trigger was tested that fires the kickers with MPS. We demonstrated that controlling the beam dump location with kickers can significantly reduce the beam losses at SCU0, as measured by fiber optic (FO) beam loss monitors (BLMs), and can also prevent a quench. A dedicated abort kicker system has been developed based on elegant simulations. A spare injection kicker was modified to produce the required waveform. Injection kicker tests, simulations, and the abort kicker design are described. Demonstration of this strategy in APS has implications for the APS Upgrade, where more SCUs are planned.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE066
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TUPJE075	Simulation Study of Injection Performance for the Advanced Photon Source Upgrade	1816
	A. Xiao, V. Sajaev ANL, Argonne, Ilinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 A vertical on-axis injection scheme has been proposed for the hybrid seven-bend-achromat (H7BA) Advanced Photon Source upgrade (APSU) lattice. In order to evaluate the injection performance, various errors, such as injection beam jitter, optical mismatch and errors, and injection element errors have been investigated and their significance has been discovered. Injection efficiency is then simulated under different error levels. Based on these simulation results, specifications and an error-budget for individual systems have been defined.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE075
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Paper

Title

Page

Commissioning Simulations for the APS Upgrade Lattice

553

V. Sajaev, M. Borland
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A hybrid seven-bend-achromat lattice has been proposed for the APS upgrade that will feature very strong focusing elements and relatively small vacuum chamber. Achieving design lattice parameters during commissioning will need to be accomplished in a short period of time to minimize dark time for APS users. We describe here start-to-end simulation of the machine commissioning beginning from first-turn trajectory correction, performing orbit and lattice correction, and finally evaluating nonlinear performance of the corrected lattice in terms of dynamic aperture and lifetime.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA010

Export •

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

MOPMA011

Evaluation of Power Supply and Alignment Tolerances for the Advanced Photons Source Upgrade

556

V. Sajaev
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The hybrid seven-bend-achromat lattice that has been proposed for the Advanced Photon Source upgrade will feature very strong focusing elements and will provide an electron beam with very low emittance. In order to be able to maintain stable operation, very tight tolerances are required for various types of errors. Here we describe evaluation of the effects of various errors including magnet power supplies, alignment, and vibration. Based on this analysis, we determine short- and long-term stability requirements

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA011

Export •

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

MOPMA013

Experience with Round Beam Operation at the Advanced Photon Source

562

A. Xiao, L. Emery, V. Sajaev, B.X. Yang
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
Very short Touschek lifetime becomes a common issue for next-generation ultra-low emittance storage ring light sources. In order to reach a longer beam lifetime, such a machine often requires operating with a vertical-to-horizontal emittance ratio close to an unity, i.e. a ‘‘round beam''. In tests at the APS storage ring, we determined how a round beam can be reached experimentally. Some general issues, such as beam injection, optics measurement and corrections, and orbit correction have been tested also. To demonstrate that a round beam was achieved, the beam size ratio is calibrated using beam lifetime measurement.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA013

Export •

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

TUPJE063

Hybrid Seven-Bend-Achromat Lattice for the Advanced Photon Source Upgrade

1776

M. Borland, V. Sajaev, Y. Sun
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A hybrid seven-bend-achromat lattice has been designed for the APS upgrade. We describe the design goals, constraints, and methodology, including the choice of beam energy. Magnet strength and spacing is compatible with engineering designs for the magnets, diagnostics, and vacuum system. Dynamic acceptance and local momentum acceptance were simulated using realistic errors, then used to assess workable injection methods and predict beam lifetime. Predicted brightness is two to three orders of magnitude higher than the existing APS storage ring. Pointers are provided to other papers in this conference that cover subjects in more detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE063

Export •

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

TUPJE064

Calibration of Fast Fiber-Optic Beam Loss Monitors for the Advanced Photon Source Storage Ring Superconducting Undulators

1780

J.C. Dooling, K.C. Harkay, Y. Ivanyushenkov, V. Sajaev, A. Xiao
ANL, Argonne, Ilinois, USA
A. Vella
University of Illinois at Urbana-Champaign, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357.
We report on the calibration and use of fast fiber-optic (FO) beam loss monitors (BLMs) in the Advanced Photon Source storage ring (SR). A superconducting undulator prototype (SCU0) has been operating in SR Sector 6 since the beginning of CY2013, and another undulator SCU1 (a 1.1-m length undulator that is three times the length of SCU0) is scheduled for installation in Sector 1 in 2015. The SCU0 main coil often quenches during beam dumps. MARS simulations have shown that relatively small beam loss (<1 nC) can lead to temperature excursions sufficient to cause quenching when the SCU0 windings are near critical current. To characterize local beam losses, high-purity fused-silica FO cables were installed in Sector 6 next to the SCU0 cryostat and in Sector 1 where SCU1 will be installed. These BLMs aid in the search for operating modes that protect the SCU structures from beam-loss-induced quenching. In this paper, we describe the BLM calibration process that included deliberate beam dumps at locations of BLMs. We also compare beam dump events where SCU0 did and did not quench.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE064

Export •

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

TUPJE066

Development of an Abort Kicker at APS to Mitigate Beam Loss-induced Quenches of the Superconducting Undulator

1787

K.C. Harkay, J.C. Dooling, Y. Ivanyushenkov, R. Laird, F. Lenkszus, C.C. Putnam, V. Sajaev, J. Wang
ANL, Argonne, Illinois, USA

Funding: Work supported by U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The first superconducting undulator (SCU0) at the Advanced Photon Source (APS) has been delivering 80-100 keV photons for user science since January 2013. SCU0 often quenches during beam dumps triggered by the machine protection system (MPS). SCU0 typically recovers quickly after a quench, but SCU1, a second, longer device to be installed in 2015, may take longer to recover. We tested using injection kickers as an abort system to dump the beam away from SCU0 and the planned location of SCU1. An alternate trigger was tested that fires the kickers with MPS. We demonstrated that controlling the beam dump location with kickers can significantly reduce the beam losses at SCU0, as measured by fiber optic (FO) beam loss monitors (BLMs), and can also prevent a quench. A dedicated abort kicker system has been developed based on elegant simulations. A spare injection kicker was modified to produce the required waveform. Injection kicker tests, simulations, and the abort kicker design are described. Demonstration of this strategy in APS has implications for the APS Upgrade, where more SCUs are planned.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE066

Export •

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

TUPJE075

Simulation Study of Injection Performance for the Advanced Photon Source Upgrade

1816

A. Xiao, V. Sajaev
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
A vertical on-axis injection scheme has been proposed for the hybrid seven-bend-achromat (H7BA) Advanced Photon Source upgrade (APSU) lattice. In order to evaluate the injection performance, various errors, such as injection beam jitter, optical mismatch and errors, and injection element errors have been investigated and their significance has been discovered. Injection efficiency is then simulated under different error levels. Based on these simulation results, specifications and an error-budget for individual systems have been defined.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE075

Export •

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