IPAC2015 - List of Authors (Meot, F.)

Paper	Title	Page
MOPJE077	Progress on Simulation of Fixed Field Alternating Gradient Accelerators	495
	S.L. Sheehy JAI, Oxford, United Kingdom A. Adelmann PSI, Villigen PSI, Switzerland M. Haj Tahar, F. Méot BNL, Upton, Long Island, New York, USA Y. Ishi, Y. Kuriyama, Y. Mori, M. Sakamoto, T. Uesugi Kyoto University, Research Reactor Institute, Osaka, Japan D.J. Kelliher, S. Machida, C.R. Prior, C.T. Rogers STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	Fixed Field Alternating Gradient accelerators have been realised in recent decades thanks partly to computational power, enabling detailed design and simulation prior to construction. We review the specific challenges of these machines and the range of different codes used to model them including ZGOUBI, OPAL and a number of in-house codes from different institutes. The current status of benchmarking between codes is presented and compared to the results of recent characterisation experiments with a 150 MeV FFAG at KURRI in Japan. Finally, we outline plans toward ever more realistic simulations including space charge, material interactions and more detailed models of various components.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE077
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MOPMN008	Space Charge Studies in FFAG Using the Tracking Code Zgoubi	717
	M. Haj Tahar, F. Méot, N. Tsoupas 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 method is implemented in Zgoubi that allows the computation of space charge effects in 2D distributions and with some restrictions in 3D distributions. It relies on decomposiing field maps or analytical elements into slices and applying a space charge kick to the particles. The aim of this study is to investigate the accuracy of this technique, its limitations/advantages by comparisons with other linear/nonlinear computation methods and codes, and to apply it to high power fixed field ring design studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMN008
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MOPMN029	Spin Resonance Strength Calculation Through Single Particle Tracking for Rhic	763
	Y. Luo, Y. Dutheil, H. Huang, F. Méot, V.H. Ranjbar 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 strengths of spin resonances for the polarized-proton operation in the Relativistic Heavy Ion Collider are currently calculated with code DEPOL, which numerically integrate through the whole ring based on analytical approximate formula. In this article, we calculate the spin resonance strength by performing Fourier transformation to the actual transverse magnetic field seen by a single particle travelling through the ring. Comparison is made between the results from this method and DEPOL and other approaches.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMN029
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MOPMN030	Proton Spin Tracking with Symplectic Integration of Orbit Motion	766
	Y. Luo, Y. Dutheil, H. Huang, F. Méot, V.H. Ranjbar 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. Symplectic integration for orbital motion had been adopted in SimTrack which has been extensively used for dynamic aperture calculation with beam-beam interaction for the Relativistic Heavy Ion Collider (RHIC). Recently spin tracking for protons has been implemented on top of the orbit motion in this code. In this article, we will explain the implementation of spin motion using Thomas-BMT equation, and benchmark with other spin tracking codes currently used for RHIC. Possibility and remedy for very-long term particle tracking, such as on the RHIC energy acceleration, is also explored.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMN030
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TUPTY047	ERL with Non-Scaling Fixed Field Alternating Gradient Lattice for eRHIC	2120
	D. Trbojevic, J.S. Berg, S.J. Brooks, Y. Hao, V. Litvinenko, C. Liu, F. Méot, M.G. Minty, V. Ptitsyn, T. Roser, P. Thieberger, N. Tsoupas BNL, Upton, Long Island, New York, USA
	Funding: Work performed under Contract Number DE-AC02-98CH10886 with the auspices of the US Department of Energy. The proposed eRHIC electron-hadron collider uses a "non-scaling FFAG" lattice to recirculate 16 turns of different energy through just two beamlines located in the RHIC tunnel. This paper presents lattices for these two FFAGs that are optimised for low magnet field and to minimise total synchrotron radiation across the energy range. The higher number of recirculations in the FFAG allows a shorter linac (1.322GeV) to be used, drastically reducing cost, while still achieving a 21.2GeV maximum energy to collide with one of the existing RHIC hadron rings at up to 250GeV. eRHIC uses many cost-saving measures in addition to the FFAG: the linac operates in energy recovery mode, so the beams also decelerate via the same FFAG loops and energy is recovered from the interacted beam. All magnets will constructed from NdFeB permanent magnet material, meaning chillers and large magnet power supplies are not needed. This paper also describes a smaller prototype ERL-FFAG accelerator that will test all of these technologies in combination to reduce technical risk for eRHIC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY047
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TUPWI049	Polarized Proton Beam for eRHIC	2360
	H. Huang, F. Méot, V. Ptitsyn, T. Roser 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. RHIC has provided polarized proton collisions from 31 GeV to 255 GeV in past decade. To preserve polarization through numerous depolarizing resonances through the whole accelerator chain, harmonic orbit correction, partial snakes, horizontal tune jump system and full snakes have been used. In addition, close attentions have been paid to betatron tune control, orbit control and beam line alignment. The polarization of 60% at 255 GeV has been delivered to experiments with 1.8×10¹¹ bunch intensity. For the eRHIC era, the beam brightness has to be maintained to reach the desired luminosity. Since we only have one hadron ring in the eRHIC era, existing spin rotator and snakes can be converted to six snake configuration for one hadron ring. With properly arranged six snakes, the polarization can be maintained at 70% at 250 GeV. This paper summarizes the effort and plan to reach high polarization with small emittance for eRHIC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI049
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TUPWI051	Study of Orbit Correction for eRHIC FFAG Design	2366
	C. Liu, Y. Hao, V. Litvinenko, F. Méot, M.G. Minty, V. Ptitsyn, D. Trbojevic 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 chromaticities in the eRHIC linear non-scaling Fixed Field Alternating Gradient (FFAG) lattice are very large. Therefore, particles will decohere in phase space given the presence of lattice errors. The decoherence causes a deviation of the orbit response which is the basis for orbit corrections. In this report we will present a study of the linearity of the orbit response in a lattice with large chromaticity, a comparison of the results of orbit corrections for several cases together with a conclusion that correcting the average orbit with a measured orbit response works as good as an orbit correction for on-momentum particles. The work was performed under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI051
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TUPWI052	End-to-end 9-D⁺SR Polarized Bunch Transport in eRHIC Energy-recovery Recirculator, Some Aspects	2369
	F. Méot, S.J. Brooks, V. Ptitsyn, D. Trbojevic, N. Tsoupas 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 energy-recovery electron beam recirculator, part of the eRHIC electron-ion collider project complex at BNL, is subject to feasibility studies in an FFAG arc based version. We develop here on tracking simulations and their analysis, regarding end-to-end polarized e-bunch transport in presence of synchrotron radiation, magnet alignment and field errors. Simulations include the evolution of energy, orbits, emittances, polarization profiles.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI052
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TUPWI053	Polarization Simulations in the RHIC Run 15 Lattice	2372
	F. Méot, H. Huang, Y. Luo, V.H. Ranjbar, G. Robert-Demolaize BNL, Upton, Long Island, New York, USA S.M. White ESRF, Grenoble, France
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. RHIC polarized proton Run 15 uses a new acceleration ramp optics, compared to RHIC Run~14 and earlier runs, in relation with electron-lens beam-beam compensation developments. The new optics induces different strengths in the depolarizing snake resonance sequence, from injection to top energy. As a consequence, polarization transport along the new ramp has been investigated, based on spin tracking simulations. Sample results are reported and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI053
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TUPWI054	9-D Polarized Proton Transport in the MEIC "Figure-8" Collider Ring - First Steps	2375
	F. Méot BNL, Upton, Long Island, New York, USA V.S. Morozov JLab, Newport News, Virginia, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Spin tracking studies in the MEIC figure-8 collider ion ring are presented, based on a preliminary design of the lattice. They provide numerical illustrations of some of the aspects of the figure-8 concept, including spin-rotator based spin control, and lay out the path towards complete spin tracking simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI054
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TUPWI055	Chromatic Effects and Orbit Correction in eRHIC Arcs	2378
	F. Méot, C. Liu 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 FFAG version of the electron energy recovery recirculator of the eRHIC electron-ion collider project, natural chromaticity is important and not corrected. Tracking simulations illustrate various aspects of its effects on 6-D bunch dynamics over the 16 turn recirculation from 1.3 to 21.2GeV collision energy, and back down to injection energy. These effects can be mitigated via orbit control, the methodology for that is described and its effectiveness illustrated via a series of ad hoc numerical simulations. Because polarization is paramount in the eRHIC NP program, its careful monitoring is part of the simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI055
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TUPWI060	RHIC Polarized Proton-Proton Operation at 100 GeV in Run 15	2384
	V. Schoefer, E.C. Aschenauer, G. Atoian, M. Blaskiewicz, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, Y. Dutheil, W. Fischer, C.J. Gardner, X. Gu, T. Hayes, H. Huang, J.S. Laster, C. Liu, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, S. Nemesure, P.H. Pile, A. Poblaguev, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, W.B. Schmidke, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, G. Wang, S.M. White, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang BNL, Upton, Long Island, New York, USA
	The first part of RHIC Run 15 consisted of nine weeks of polarized proton on proton collisions at a beam energy of 100 GeV at two interaction points. In this paper we discuss several of the upgrades to the collider complex that allowed for improved performance this run. The largest effort consisted of commissioning of the electron lenses, one in each ring, which are designed to compensate one of the two beam-beam interactions experienced by the proton bunches. The e-lenses therefore raise the per bunch intensity at which luminosity becomes beam-beam limited. A new lattice was designed to create the phase advances necessary for a functioning e-lens which also has an improved off-momentum dynamic aperture relative to previous runs. In order to take advantage of the new, higher intensity limit without suffering intensity driven emittance deterioration, other features were commissioned including a continuous transverse bunch-by-bunch damper in RHIC and a double harmonic capture scheme in the Booster. Other high intensity protections include improvements to the abort system and the installation of masks to intercept beam lost due to abort kicker pre-fires.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI060
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Paper

Title

Page

Progress on Simulation of Fixed Field Alternating Gradient Accelerators

495

S.L. Sheehy
JAI, Oxford, United Kingdom
A. Adelmann
PSI, Villigen PSI, Switzerland
M. Haj Tahar, F. Méot
BNL, Upton, Long Island, New York, USA
Y. Ishi, Y. Kuriyama, Y. Mori, M. Sakamoto, T. Uesugi
Kyoto University, Research Reactor Institute, Osaka, Japan
D.J. Kelliher, S. Machida, C.R. Prior, C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

Fixed Field Alternating Gradient accelerators have been realised in recent decades thanks partly to computational power, enabling detailed design and simulation prior to construction. We review the specific challenges of these machines and the range of different codes used to model them including ZGOUBI, OPAL and a number of in-house codes from different institutes. The current status of benchmarking between codes is presented and compared to the results of recent characterisation experiments with a 150 MeV FFAG at KURRI in Japan. Finally, we outline plans toward ever more realistic simulations including space charge, material interactions and more detailed models of various components.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE077

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MOPMN008

Space Charge Studies in FFAG Using the Tracking Code Zgoubi

717

M. Haj Tahar, F. Méot, N. Tsoupas
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 method is implemented in Zgoubi that allows the computation of space charge effects in 2D distributions and with some restrictions in 3D distributions. It relies on decomposiing field maps or analytical elements into slices and applying a space charge kick to the particles. The aim of this study is to investigate the accuracy of this technique, its limitations/advantages by comparisons with other linear/nonlinear computation methods and codes, and to apply it to high power fixed field ring design studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMN008

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MOPMN029

Spin Resonance Strength Calculation Through Single Particle Tracking for Rhic

763

Y. Luo, Y. Dutheil, H. Huang, F. Méot, V.H. Ranjbar
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 strengths of spin resonances for the polarized-proton operation in the Relativistic Heavy Ion Collider are currently calculated with code DEPOL, which numerically integrate through the whole ring based on analytical approximate formula. In this article, we calculate the spin resonance strength by performing Fourier transformation to the actual transverse magnetic field seen by a single particle travelling through the ring. Comparison is made between the results from this method and DEPOL and other approaches.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMN029

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MOPMN030

Proton Spin Tracking with Symplectic Integration of Orbit Motion

766

Y. Luo, Y. Dutheil, H. Huang, F. Méot, V.H. Ranjbar
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.
Symplectic integration for orbital motion had been adopted in SimTrack which has been extensively used for dynamic aperture calculation with beam-beam interaction for the Relativistic Heavy Ion Collider (RHIC). Recently spin tracking for protons has been implemented on top of the orbit motion in this code. In this article, we will explain the implementation of spin motion using Thomas-BMT equation, and benchmark with other spin tracking codes currently used for RHIC. Possibility and remedy for very-long term particle tracking, such as on the RHIC energy acceleration, is also explored.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMN030

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TUPTY047

ERL with Non-Scaling Fixed Field Alternating Gradient Lattice for eRHIC

2120

D. Trbojevic, J.S. Berg, S.J. Brooks, Y. Hao, V. Litvinenko, C. Liu, F. Méot, M.G. Minty, V. Ptitsyn, T. Roser, P. Thieberger, N. Tsoupas
BNL, Upton, Long Island, New York, USA

Funding: Work performed under Contract Number DE-AC02-98CH10886 with the auspices of the US Department of Energy.
The proposed eRHIC electron-hadron collider uses a "non-scaling FFAG" lattice to recirculate 16 turns of different energy through just two beamlines located in the RHIC tunnel. This paper presents lattices for these two FFAGs that are optimised for low magnet field and to minimise total synchrotron radiation across the energy range. The higher number of recirculations in the FFAG allows a shorter linac (1.322GeV) to be used, drastically reducing cost, while still achieving a 21.2GeV maximum energy to collide with one of the existing RHIC hadron rings at up to 250GeV. eRHIC uses many cost-saving measures in addition to the FFAG: the linac operates in energy recovery mode, so the beams also decelerate via the same FFAG loops and energy is recovered from the interacted beam. All magnets will constructed from NdFeB permanent magnet material, meaning chillers and large magnet power supplies are not needed. This paper also describes a smaller prototype ERL-FFAG accelerator that will test all of these technologies in combination to reduce technical risk for eRHIC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY047

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TUPWI049

Polarized Proton Beam for eRHIC

2360

H. Huang, F. Méot, V. Ptitsyn, T. Roser
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.
RHIC has provided polarized proton collisions from 31 GeV to 255 GeV in past decade. To preserve polarization through numerous depolarizing resonances through the whole accelerator chain, harmonic orbit correction, partial snakes, horizontal tune jump system and full snakes have been used. In addition, close attentions have been paid to betatron tune control, orbit control and beam line alignment. The polarization of 60% at 255 GeV has been delivered to experiments with 1.8×10¹¹ bunch intensity. For the eRHIC era, the beam brightness has to be maintained to reach the desired luminosity. Since we only have one hadron ring in the eRHIC era, existing spin rotator and snakes can be converted to six snake configuration for one hadron ring. With properly arranged six snakes, the polarization can be maintained at 70% at 250 GeV. This paper summarizes the effort and plan to reach high polarization with small emittance for eRHIC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI049

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TUPWI051

Study of Orbit Correction for eRHIC FFAG Design

2366

C. Liu, Y. Hao, V. Litvinenko, F. Méot, M.G. Minty, V. Ptitsyn, D. Trbojevic
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 chromaticities in the eRHIC linear non-scaling Fixed Field Alternating Gradient (FFAG) lattice are very large. Therefore, particles will decohere in phase space given the presence of lattice errors. The decoherence causes a deviation of the orbit response which is the basis for orbit corrections. In this report we will present a study of the linearity of the orbit response in a lattice with large chromaticity, a comparison of the results of orbit corrections for several cases together with a conclusion that correcting the average orbit with a measured orbit response works as good as an orbit correction for on-momentum particles.
The work was performed under Contract No. DE-AC02-98CH10886
with the U.S. Department of Energy.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI051

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TUPWI052

End-to-end 9-D⁺SR Polarized Bunch Transport in eRHIC Energy-recovery Recirculator, Some Aspects

2369

F. Méot, S.J. Brooks, V. Ptitsyn, D. Trbojevic, N. Tsoupas
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 energy-recovery electron beam recirculator, part of the eRHIC electron-ion collider project complex at BNL, is subject to feasibility studies in an FFAG arc based version. We develop here on tracking simulations and their analysis, regarding end-to-end polarized e-bunch transport in presence of synchrotron radiation, magnet alignment and field errors. Simulations include the evolution of energy, orbits, emittances, polarization profiles.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI052

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TUPWI053

Polarization Simulations in the RHIC Run 15 Lattice

2372

F. Méot, H. Huang, Y. Luo, V.H. Ranjbar, G. Robert-Demolaize
BNL, Upton, Long Island, New York, USA
S.M. White
ESRF, Grenoble, France

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
RHIC polarized proton Run 15 uses a new acceleration ramp optics, compared to RHIC Run~14 and earlier runs, in relation with electron-lens beam-beam compensation developments. The new optics induces different strengths in the depolarizing snake resonance sequence, from injection to top energy. As a consequence, polarization transport along the new ramp has been investigated, based on spin tracking simulations. Sample results are reported and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI053

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TUPWI054

9-D Polarized Proton Transport in the MEIC "Figure-8" Collider Ring - First Steps

2375

F. Méot
BNL, Upton, Long Island, New York, USA
V.S. Morozov
JLab, Newport News, Virginia, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Spin tracking studies in the MEIC figure-8 collider ion ring are presented, based on a preliminary design of the lattice. They provide numerical illustrations of some of the aspects of the figure-8 concept, including spin-rotator based spin control, and lay out the path towards complete spin tracking simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI054

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TUPWI055

Chromatic Effects and Orbit Correction in eRHIC Arcs

2378

F. Méot, C. Liu
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 FFAG version of the electron energy recovery recirculator of the eRHIC electron-ion collider project, natural chromaticity is important and not corrected. Tracking simulations illustrate various aspects of its effects on 6-D bunch dynamics over the 16 turn recirculation from 1.3 to 21.2GeV collision energy, and back down to injection energy. These effects can be mitigated via orbit control, the methodology for that is described and its effectiveness illustrated via a series of ad hoc numerical simulations. Because polarization is paramount in the eRHIC NP program, its careful monitoring is part of the simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI055

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TUPWI060

RHIC Polarized Proton-Proton Operation at 100 GeV in Run 15

2384

V. Schoefer, E.C. Aschenauer, G. Atoian, M. Blaskiewicz, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, Y. Dutheil, W. Fischer, C.J. Gardner, X. Gu, T. Hayes, H. Huang, J.S. Laster, C. Liu, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, S. Nemesure, P.H. Pile, A. Poblaguev, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, W.B. Schmidke, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, G. Wang, S.M. White, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang
BNL, Upton, Long Island, New York, USA

The first part of RHIC Run 15 consisted of nine weeks of polarized proton on proton collisions at a beam energy of 100 GeV at two interaction points. In this paper we discuss several of the upgrades to the collider complex that allowed for improved performance this run. The largest effort consisted of commissioning of the electron lenses, one in each ring, which are designed to compensate one of the two beam-beam interactions experienced by the proton bunches. The e-lenses therefore raise the per bunch intensity at which luminosity becomes beam-beam limited. A new lattice was designed to create the phase advances necessary for a functioning e-lens which also has an improved off-momentum dynamic aperture relative to previous runs. In order to take advantage of the new, higher intensity limit without suffering intensity driven emittance deterioration, other features were commissioned including a continuous transverse bunch-by-bunch damper in RHIC and a double harmonic capture scheme in the Booster. Other high intensity protections include improvements to the abort system and the installation of masks to intercept beam lost due to abort kicker pre-fires.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI060

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