IPAC2015 - List of Authors (Wang, J.)

Paper	Title	Page
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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TUPJE069	Fast Injection System R&D for the APS Upgrade	1797
	F. Lenkszus, J. Carwardine, A.R. Cours, G. Decker, L.H. Morrison, X. Sun, J. Wang, F. Westferro, A. Xiao, C. Yao ANL, Argonne, Ilinois, USA A. Krasnykh SLAC, Menlo Park, California, USA
	Funding: Results in this report are derived from work performed at Argonne National Laboratory. Argonne is operated by UChicago Argonne, LLC, for the U.S. Department of Energy under contract DE-AC02-06CH11357. The MBA upgrade for the APS will operate with bunch swap out and on axis injection. The planned 324 bunch fill pattern places difficult demands on the injection and extraction kickers. The present concept uses dual stripline kickers driven by high Voltage pulsers. Minimizing perturbation on adjacent bunches requires very fast rise and fall times with relatively narrow ~20 nsec, 15 kV pulses. To achieve these requirements we have initiated a multifaceted R&D program. The R&D includes the HV pulser, stripline kicker and HV feedthrough. We have purchased a commercial dual channel HV pulser and are evaluating its performance and reliability. In addition, we are investigating the feasibility of using nonlinear ferrite loaded coaxial cables (shockwave transmission line) to sharpen the leading and trailing edges of high voltage pulses. We are also developing a prototype kicker and high voltage feedthrough. The requirements for injection and extraction, progress on prototype development and results of our HV pulser investigations will be reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE069
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TUPJE079	High Charge Development of the APS Injector for an MBA Upgrade	1828
	C. Yao, M. Borland, J.R. Calvey, K.C. Harkay, D. Horan, R.R. Lindberg, N. Sereno, H. Shang, X. Sun, J. Wang ANL, Argonne, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The APS MBA (multi-bend achromat) upgrade storage ring will employ a “swap out” injection scheme and requires a single-bunch beam with up to 20 nC from the injector. The APS injector, which consists of a 450-MeV linac, a particle accumulator ring (PAR), and a 7-GeV synchrotron (Booster), was originally designed to provide up to 6 nC of beam charge. High charge injector study is part of the APS upgrade R&D that explores the capabilities and limitations of the injector through machine studies and simulations, and identifies necessary upgrades in order to meet the requirements of the MBA upgrade. In the past year we performed PAR and booster high charge studies, implemented new ramp correction of the booster rap supplies, explored non-linear chromatic correction of the booster, etc. This report presents the results and findings.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE079
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WEPTY004	Mathematical Modeling and Analysis of a Wide Bandwidth Bipolar Power Supply for the Fast Correctors in the APS Upgrade Controller	3264
	B. Song, J. Wang ANL, Argonne, Illinois, 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 APS Upgrade requires a fast bipolar power supply for the fast correction magnets. The performance requirement of the power supply includes a -3dB at 10 kHz small-signal bandwidth for the output current. This requirement presents a technical challenge to the design of the power circuit and the power supply regulator because the magnet load may have a significant inductance and make it difficult to achieve a high bandwidth for the current. In order to meet the requirement, different circuit topologies and regulators are being investigated. One of the candidate designs combines a standard H-bridge pulse-width modulation (PWM) circuit and a linear power amplifier to provide a ±15A DC current and an AC component up to 1% of the full scale with the required bandwidth. An appropriate feedback control loop and a current regulator are being designed. The mathematical modeling and simulation of the power circuit and the control loop are being conducted to prove the concept of the design. This paper presents the design of the circuit, mathematical modeling, and the simulation results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY004
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WEPTY011	Power Supply Conceptual Design and R&D for the APS Upgrade	3276
	J. Wang, B. Deriy, T. Fors, R.T. Keane, B. Song 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 MBA upgrade for the APS requires a large number of power supplies with either unipolar or bipolar DC output currents. The unipolar power supplies will be used to power the main coils in the dipole, quadrupole, and sextupole magnets and the bipolar power supplies will be used for the trim or correction coils. There are several demanding requirements of the power supplies. The unipolar power supplies are expected to have a current stability within 10 parts per million (ppm) of the full scale. The currents must be calibrated to the specification and confirmed with independent and accurate measurement. The bipolar power supplies for the fast correction magnets are required to have a wide output current bandwidth in order to minimize the impact on the real-time feedback system for the beam position correction. There are also new requirements for the power supply controls and communications that are much more demanding than that in the existing APS accelerators. This paper will report the conceptual designs of the power supply systems and the R&D program that is developed to find solutions to the technical challenges.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY011
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WEPTY014	Development of Fast Kickers for the APS MBA Upgrade	3286
	C. Yao, J. Carwardine, A.R. Cours, F. Lenkszus, R.R. Lindberg, L.H. Morrison, X. Sun, J. Wang, F. Westferro, A. Xiao ANL, Argonne, Ilinois, USA
	Funding: *Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The APS multi-bend achromat (MBA) upgrade storage ring will support two bunch fill patterns: a 48-singlets and a 324-singlets. A “swap out” injection scheme is adopted. In order to minimize the beam loss and residual oscillation of injected beam and to minimize the perturbation of stored beam during a swap-on injection, the rise, fall, and flat-top parts of the kicker pulse must be held within a 22.8-ns interval. Traditional ferrite-core-type kickers can’t meet the timing requirements; therefore, we decided to use stripline-type kickers. We have completed a preliminary design of a prototype kicker geometry. Procurement of the pulser supply and other components of an evaluation system is under way. We report the specification and design of the fast kicker and current status.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY014
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Paper

Title

Page

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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TUPJE069

Fast Injection System R&D for the APS Upgrade

1797

F. Lenkszus, J. Carwardine, A.R. Cours, G. Decker, L.H. Morrison, X. Sun, J. Wang, F. Westferro, A. Xiao, C. Yao
ANL, Argonne, Ilinois, USA
A. Krasnykh
SLAC, Menlo Park, California, USA

Funding: Results in this report are derived from work performed at Argonne National Laboratory. Argonne is operated by UChicago Argonne, LLC, for the U.S. Department of Energy under contract DE-AC02-06CH11357.
The MBA upgrade for the APS will operate with bunch swap out and on axis injection. The planned 324 bunch fill pattern places difficult demands on the injection and extraction kickers. The present concept uses dual stripline kickers driven by high Voltage pulsers. Minimizing perturbation on adjacent bunches requires very fast rise and fall times with relatively narrow ~20 nsec, 15 kV pulses. To achieve these requirements we have initiated a multifaceted R&D program. The R&D includes the HV pulser, stripline kicker and HV feedthrough. We have purchased a commercial dual channel HV pulser and are evaluating its performance and reliability. In addition, we are investigating the feasibility of using nonlinear ferrite loaded coaxial cables (shockwave transmission line) to sharpen the leading and trailing edges of high voltage pulses. We are also developing a prototype kicker and high voltage feedthrough. The requirements for injection and extraction, progress on prototype development and results of our HV pulser investigations will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE069

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TUPJE079

High Charge Development of the APS Injector for an MBA Upgrade

1828

C. Yao, M. Borland, J.R. Calvey, K.C. Harkay, D. Horan, R.R. Lindberg, N. Sereno, H. Shang, X. Sun, J. Wang
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The APS MBA (multi-bend achromat) upgrade storage ring will employ a “swap out” injection scheme and requires a single-bunch beam with up to 20 nC from the injector. The APS injector, which consists of a 450-MeV linac, a particle accumulator ring (PAR), and a 7-GeV synchrotron (Booster), was originally designed to provide up to 6 nC of beam charge. High charge injector study is part of the APS upgrade R&D that explores the capabilities and limitations of the injector through machine studies and simulations, and identifies necessary upgrades in order to meet the requirements of the MBA upgrade. In the past year we performed PAR and booster high charge studies, implemented new ramp correction of the booster rap supplies, explored non-linear chromatic correction of the booster, etc. This report presents the results and findings.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE079

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WEPTY004

Mathematical Modeling and Analysis of a Wide Bandwidth Bipolar Power Supply for the Fast Correctors in the APS Upgrade Controller

3264

B. Song, J. Wang
ANL, Argonne, Illinois, 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 APS Upgrade requires a fast bipolar power supply for the fast correction magnets. The performance requirement of the power supply includes a -3dB at 10 kHz small-signal bandwidth for the output current. This requirement presents a technical challenge to the design of the power circuit and the power supply regulator because the magnet load may have a significant inductance and make it difficult to achieve a high bandwidth for the current. In order to meet the requirement, different circuit topologies and regulators are being investigated. One of the candidate designs combines a standard H-bridge pulse-width modulation (PWM) circuit and a linear power amplifier to provide a ±15A DC current and an AC component up to 1% of the full scale with the required bandwidth. An appropriate feedback control loop and a current regulator are being designed. The mathematical modeling and simulation of the power circuit and the control loop are being conducted to prove the concept of the design. This paper presents the design of the circuit, mathematical modeling, and the simulation results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY004

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WEPTY011

Power Supply Conceptual Design and R&D for the APS Upgrade

3276

J. Wang, B. Deriy, T. Fors, R.T. Keane, B. Song
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 MBA upgrade for the APS requires a large number of power supplies with either unipolar or bipolar DC output currents. The unipolar power supplies will be used to power the main coils in the dipole, quadrupole, and sextupole magnets and the bipolar power supplies will be used for the trim or correction coils. There are several demanding requirements of the power supplies. The unipolar power supplies are expected to have a current stability within 10 parts per million (ppm) of the full scale. The currents must be calibrated to the specification and confirmed with independent and accurate measurement. The bipolar power supplies for the fast correction magnets are required to have a wide output current bandwidth in order to minimize the impact on the real-time feedback system for the beam position correction. There are also new requirements for the power supply controls and communications that are much more demanding than that in the existing APS accelerators. This paper will report the conceptual designs of the power supply systems and the R&D program that is developed to find solutions to the technical challenges.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY011

Export •

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

WEPTY014

Development of Fast Kickers for the APS MBA Upgrade

3286

C. Yao, J. Carwardine, A.R. Cours, F. Lenkszus, R.R. Lindberg, L.H. Morrison, X. Sun, J. Wang, F. Westferro, A. Xiao
ANL, Argonne, Ilinois, USA

Funding: *Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The APS multi-bend achromat (MBA) upgrade storage ring will support two bunch fill patterns: a 48-singlets and a 324-singlets. A “swap out” injection scheme is adopted. In order to minimize the beam loss and residual oscillation of injected beam and to minimize the perturbation of stored beam during a swap-on injection, the rise, fall, and flat-top parts of the kicker pulse must be held within a 22.8-ns interval. Traditional ferrite-core-type kickers can’t meet the timing requirements; therefore, we decided to use stripline-type kickers. We have completed a preliminary design of a prototype kicker geometry. Procurement of the pulser supply and other components of an evaluation system is under way. We report the specification and design of the fast kicker and current status.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY014

Export •

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