IPAC2017 - List of Authors (Schoefer, V.)

Paper	Title	Page
MOPAB154	Measurement of Proton Transverse Emittance in the Brookhaven AGS	494
	H. Huang, L. Ahrens, C.W. Dawson, C.E. Harper, C. Liu, F. Méot, M.G. Minty, V. Schoefer, S. Tepikian, K. Zeno BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. High luminosity and high polarization in RHIC require good control and measurement of emittance in its injector, the Brookhaven AGS. In the past, the AGS emittance has been measured by using an ion collecting IPM during the whole cycle. The beam profiles from this IPM are distorted by space charge forces at higher energy, which makes the emittance determination very hard. The effect has been measured with IPM measurement at different energies with RF off to mitigate the space charge effect. In addition, helical snake magnets and near integer vertical tune for polarized proton operation distort the lattice in the AGS and introduce large beta beating. For more precise measurements of the emittance, we need turn-by-turn (TBT) measurements near injection and beta function measurements at the IPM. The AGS has also been modeled to get the beta functions at the locations of IPM. A new type of electron collecting IPM has been installed and tested in the AGS with proton beam. The vertical beta functions at the IPM locations have been measured with a local corrector near the IPM. This paper summarizes our current understanding of AGS emittances and plans for the further improvements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB154
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TUPVA045	Compensation of Head-on Beam-Beam Induced Resonance Driving Terms and Tune Spread in the Relativistic Heavy Ion Collider	2171
	W. Fischer, X. Gu, C. Liu, Y. Luo, A. Marusic, R.J. Michnoff, T.A. Miller, M.G. Minty, C. Montag, A.I. Pikin, G. Robert-Demolaize, V. Schoefer, P. Thieberger BNL, Upton, Long Island, New York, USA S.M. White ESRF, Grenoble, France
	Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy. A head-on beam-beam compensation scheme was implemented for operation in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The compensation consists of a lattice for the minimization of beam-beam driven resonance driving terms, and electron lenses for the reduction of the beam-beam induced tune spread. We describe the implementations of the lattice and electron lenses, and report on measurements of lattice properties and the effect of the electron lenses on the hadron beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA045
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TUPVA046	Beam Energy Scan With Asymmetric Collision at RHIC	2175
	C. Liu, J.G. Alessi, E.N. Beebe, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, J.J. Butler, R. Connolly, T. D'Ottavio, K.A. Drees, W. Fischer, C.J. Gardner, D.M. Gassner, X. Gu, Y. Hao, M. Harvey, T. Hayes, H. Huang, R.L. Hulsart, P.F. Ingrassia, J.P. Jamilkowski, J.S. Laster, V. Litvinenko, Y. Luo, M. Mapes, G.J. Marr, A. Marusic, G.T. McIntyre, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, C. Naylor, S. Nemesure, I. Pinayev, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, T. Roser, P. Sampson, J. Sandberg, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, S. Tepikian, R. Than, P. Thieberger, J.E. Tuozzolo, G. Wang, Q. Wu, A. Zaltsman, K. Zeno, S.Y. Zhang, W. Zhang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. A beam energy scan of deuteron-gold collision, with center-of-mass energy at 19.6, 39, 62.4 and 200.7 GeV/n, was performed at the Relativistic Heavy Ion Collider in 2016 to study the threshold for quark-gluon plasma (QGP) production. The lattice, RF, stochastic cooling and other subsystems were in different configurations for the various energies. The operational challenges changed with every new energy. The operational experience at each energy, the operation performance, highlights and lessons of the beam energy scan are reviewed in this report.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA046
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TUPVA048	Calculation of Particle Loss Maps for 2016 RHIC Gold-Gold Run	2181
	Y. Luo, K.A. Drees, W. Fischer, X. Gu, A. Marusic, G. Robert-Demolaize, V. Schoefer BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In the 2016 RHIC 100~GeV gold-gold (Au-Au) run, 20~mm orbit bumps were installed in the arcs to protect the experimental detectors from abort kicker prefiring. Chronic particle losses were observed in the arcs with these orbit bumps. Those particle losses are mainly from the 78+Au197 and 79+Au196 particles generated from bound-free pair production (BFPP) and electromagnetic dissociation (EMD) associated with the Au-Au collision at the IPs. In this article, we present simulated particle losses of 78+Au197 and 79+Au196 and calculate the particle loss distribution in the ring. The calculated particle loss maps are compared with operational observations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA048
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TUPVA050	RHIC Polarized Proton Operation for 2017	2188
	V.H. Ranjbar, P. Adams, Z. Altinbas, E.C. Aschenauer, G. Atoian, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, M.R. Costanzo, T. D'Ottavio, K.A. Drees, P.S. Dyer, A.V. Fedotov, W. Fischer, C.J. Gardner, D.M. Gassner, X. Gu, C.E. Harper, M. Harvey, T. Hayes, J. Hock, H. Huang, R.L. Hulsart, J.P. Jamilkowski, T. Kanesue, N.A. Kling, J.S. Laster, C. Liu, Y. Luo, D. Maffei, M. Mapes, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, T.A. Miller, M.G. Minty, C. Montag, J. Morris, G. Narayan, C. Naylor, S. Nemesure, P. Oddo, M. Okamura, S. Perez, A.I. Pikin, A. Poblaguev, S. Polizzo, V. Ptitsyn, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, W.B. Schmidke, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, Z. Sorrell, D. Steski, S. Tepikian, R. Than, P. Thieberger, J.E. Tuozzolo, G. Wang, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, W. Zhang, B. van Kuik BNL, Upton, Long Island, New York, USA
	Funding: Work supported by the US Department of Energy under contract number DE-SC0012704 The 2017 operation of the Relativistic Heavy Ion Collider (RHIC) involved the running of only a single experiment at STAR with PHENIX offline in the process of the upgrade to sPHENIX. For this run there were several notable changes to machine operations. These included, transverse polarization, luminosity leveling, a new approach to machine protection and the development of new store and ramped lattices. The new 255 GeV store lattice was designed to both accommodate the necessary phase advance between the e-lens and IP8 for testing and to maximize dynamic aperture. The new lattices on the ramp were designed to maximize polarization transmission during the three strong intrinsic spin resonances crossings. Finally we are also commissioning new 9 MHz RF cavities during this run.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA050
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TUPVA149	AGS Polarized Proton Operation Experience in RHIC Run17	2452
	H. Huang, P. Adams, J. Beebe-Wang, M. Blaskiewicz, K.A. Brown, C.J. Gardner, C.E. Harper, C. Liu, F. Méot, J. Morris, A. Poblaguev, V.H. Ranjbar, D. Raparia, T. Roser, V. Schoefer, S. Tepikian, N. Tsoupas, K. Yip, A. Zelenski, K. Zeno BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Imperfection and vertical intrinsic depolarizing resonances have been overcome by the two partial Siberian snakes in the Alternating Gradient Synchrotron (AGS). The relatively weak but numerous horizontal resonances are overcome by a pair of horizontal tune jump quads. 70% proton polarization has been achieved for 2·10¹¹ intensity. Further gain can come from maintaining smaller transverse emittance with same beam intensity. The main efforts now are to reduce the transverse emittance in the AGS and Booster, as well as robust jump quads timing generation scheme. This paper summarizes the operation results in the injectors.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA149
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WEPVA041	Rematching AGS Booster Synchrotron Injection Lattice for Smaller Transverse Beam Emittances	3353
	C. Liu, J. Beebe-Wang, K.A. Brown, C.J. Gardner, H. Huang, M.G. Minty, V. Schoefer, K. Zeno BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The polarized proton beam is injected into the booster via the charge-exchange (H⁻ to H⁺) scheme. The emittance growth due to scattering at the stripping foil is proportional to the beta functions at the foil. It was demonstrated that the current scheme of reducing the beta functions at the stripping foil preserves the emittance better, however the betatron tunes are above but very close to half integer. Due to concern of space charge and half integer in general, options of lattice designs aimed towards reducing the beta functions at the stripping foil with tunes at more favorable places are explored.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA041
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Paper

Title

Page

Measurement of Proton Transverse Emittance in the Brookhaven AGS

494

H. Huang, L. Ahrens, C.W. Dawson, C.E. Harper, C. Liu, F. Méot, M.G. Minty, V. Schoefer, S. Tepikian, K. Zeno
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
High luminosity and high polarization in RHIC require good control and measurement of emittance in its injector, the Brookhaven AGS. In the past, the AGS emittance has been measured by using an ion collecting IPM during the whole cycle. The beam profiles from this IPM are distorted by space charge forces at higher energy, which makes the emittance determination very hard. The effect has been measured with IPM measurement at different energies with RF off to mitigate the space charge effect. In addition, helical snake magnets and near integer vertical tune for polarized proton operation distort the lattice in the AGS and introduce large beta beating. For more precise measurements of the emittance, we need turn-by-turn (TBT) measurements near injection and beta function measurements at the IPM. The AGS has also been modeled to get the beta functions at the locations of IPM. A new type of electron collecting IPM has been installed and tested in the AGS with proton beam. The vertical beta functions at the IPM locations have been measured with a local corrector near the IPM. This paper summarizes our current understanding of AGS emittances and plans for the further improvements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB154

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TUPVA045

Compensation of Head-on Beam-Beam Induced Resonance Driving Terms and Tune Spread in the Relativistic Heavy Ion Collider

2171

W. Fischer, X. Gu, C. Liu, Y. Luo, A. Marusic, R.J. Michnoff, T.A. Miller, M.G. Minty, C. Montag, A.I. Pikin, G. Robert-Demolaize, V. Schoefer, P. Thieberger
BNL, Upton, Long Island, New York, USA
S.M. White
ESRF, Grenoble, France

Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
A head-on beam-beam compensation scheme was implemented for operation in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The compensation consists of a lattice for the minimization of beam-beam driven resonance driving terms, and electron lenses for the reduction of the beam-beam induced tune spread. We describe the implementations of the lattice and electron lenses, and report on measurements of lattice properties and the effect of the electron lenses on the hadron beam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA045

Export •

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

TUPVA046

Beam Energy Scan With Asymmetric Collision at RHIC

2175

C. Liu, J.G. Alessi, E.N. Beebe, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, J.J. Butler, R. Connolly, T. D'Ottavio, K.A. Drees, W. Fischer, C.J. Gardner, D.M. Gassner, X. Gu, Y. Hao, M. Harvey, T. Hayes, H. Huang, R.L. Hulsart, P.F. Ingrassia, J.P. Jamilkowski, J.S. Laster, V. Litvinenko, Y. Luo, M. Mapes, G.J. Marr, A. Marusic, G.T. McIntyre, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, C. Naylor, S. Nemesure, I. Pinayev, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, T. Roser, P. Sampson, J. Sandberg, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, S. Tepikian, R. Than, P. Thieberger, J.E. Tuozzolo, G. Wang, Q. Wu, A. Zaltsman, K. Zeno, S.Y. Zhang, W. Zhang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A beam energy scan of deuteron-gold collision, with center-of-mass energy at 19.6, 39, 62.4 and 200.7 GeV/n, was performed at the Relativistic Heavy Ion Collider in 2016 to study the threshold for quark-gluon plasma (QGP) production. The lattice, RF, stochastic cooling and other subsystems were in different configurations for the various energies. The operational challenges changed with every new energy. The operational experience at each energy, the operation performance, highlights and lessons of the beam energy scan are reviewed in this report.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA046

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TUPVA048

Calculation of Particle Loss Maps for 2016 RHIC Gold-Gold Run

2181

Y. Luo, K.A. Drees, W. Fischer, X. Gu, A. Marusic, G. Robert-Demolaize, V. Schoefer
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In the 2016 RHIC 100~GeV gold-gold (Au-Au) run, 20~mm orbit bumps were installed in the arcs to protect the experimental detectors from abort kicker prefiring. Chronic particle losses were observed in the arcs with these orbit bumps. Those particle losses are mainly from the 78+Au197 and 79+Au196 particles generated from bound-free pair production (BFPP) and electromagnetic dissociation (EMD) associated with the Au-Au collision at the IPs. In this article, we present simulated particle losses of 78+Au197 and 79+Au196 and calculate the particle loss distribution in the ring. The calculated particle loss maps are compared with operational observations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA048

Export •

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

TUPVA050

RHIC Polarized Proton Operation for 2017

2188

V.H. Ranjbar, P. Adams, Z. Altinbas, E.C. Aschenauer, G. Atoian, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, M.R. Costanzo, T. D'Ottavio, K.A. Drees, P.S. Dyer, A.V. Fedotov, W. Fischer, C.J. Gardner, D.M. Gassner, X. Gu, C.E. Harper, M. Harvey, T. Hayes, J. Hock, H. Huang, R.L. Hulsart, J.P. Jamilkowski, T. Kanesue, N.A. Kling, J.S. Laster, C. Liu, Y. Luo, D. Maffei, M. Mapes, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, T.A. Miller, M.G. Minty, C. Montag, J. Morris, G. Narayan, C. Naylor, S. Nemesure, P. Oddo, M. Okamura, S. Perez, A.I. Pikin, A. Poblaguev, S. Polizzo, V. Ptitsyn, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, W.B. Schmidke, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, Z. Sorrell, D. Steski, S. Tepikian, R. Than, P. Thieberger, J.E. Tuozzolo, G. Wang, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, W. Zhang, B. van Kuik
BNL, Upton, Long Island, New York, USA

Funding: Work supported by the US Department of Energy under contract number DE-SC0012704
The 2017 operation of the Relativistic Heavy Ion Collider (RHIC) involved the running of only a single experiment at STAR with PHENIX offline in the process of the upgrade to sPHENIX. For this run there were several notable changes to machine operations. These included, transverse polarization, luminosity leveling, a new approach to machine protection and the development of new store and ramped lattices. The new 255 GeV store lattice was designed to both accommodate the necessary phase advance between the e-lens and IP8 for testing and to maximize dynamic aperture. The new lattices on the ramp were designed to maximize polarization transmission during the three strong intrinsic spin resonances crossings. Finally we are also commissioning new 9 MHz RF cavities during this run.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA050

Export •

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

TUPVA149

AGS Polarized Proton Operation Experience in RHIC Run17

2452

H. Huang, P. Adams, J. Beebe-Wang, M. Blaskiewicz, K.A. Brown, C.J. Gardner, C.E. Harper, C. Liu, F. Méot, J. Morris, A. Poblaguev, V.H. Ranjbar, D. Raparia, T. Roser, V. Schoefer, S. Tepikian, N. Tsoupas, K. Yip, A. Zelenski, K. Zeno
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Imperfection and vertical intrinsic depolarizing resonances have been overcome by the two partial Siberian snakes in the Alternating Gradient Synchrotron (AGS). The relatively weak but numerous horizontal resonances are overcome by a pair of horizontal tune jump quads. 70% proton polarization has been achieved for 2·10¹¹ intensity. Further gain can come from maintaining smaller transverse emittance with same beam intensity. The main efforts now are to reduce the transverse emittance in the AGS and Booster, as well as robust jump quads timing generation scheme. This paper summarizes the operation results in the injectors.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA149

Export •

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

WEPVA041

Rematching AGS Booster Synchrotron Injection Lattice for Smaller Transverse Beam Emittances

3353

C. Liu, J. Beebe-Wang, K.A. Brown, C.J. Gardner, H. Huang, M.G. Minty, V. Schoefer, K. Zeno
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The polarized proton beam is injected into the booster via the charge-exchange (H⁻ to H⁺) scheme. The emittance growth due to scattering at the stripping foil is proportional to the beta functions at the foil. It was demonstrated that the current scheme of reducing the beta functions at the stripping foil preserves the emittance better, however the betatron tunes are above but very close to half integer. Due to concern of space charge and half integer in general, options of lattice designs aimed towards reducing the beta functions at the stripping foil with tunes at more favorable places are explored.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA041

Export •

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