IPAC2014 - List of Authors (Gupta, R.C.)

Paper	Title	Page
MOPRI064	First Test Results from SRF Photoinjector for the R&D ERL at BNL	748
	D. Kayran, Z. Altinbas, D.R. Beavis, S.A. Belomestnykh, I. Ben-Zvi, J. Dai, S. Deonarine, D.M. Gassner, R.C. Gupta, H. Hahn, L.R. Hammons, C. Ho, J.P. Jamilkowski, P. Kankiya, N. Laloudakis, R.F. Lambiase, V. Litvinenko, G.J. Mahler, L. Masi, G.T. McIntyre, T.A. Miller, D. Phillips, V. Ptitsyn, T. Rao, T. Seda, B. Sheehy, K.S. Smith, A.N. Steszyn, T.N. Tallerico, R. Than, R.J. Todd, E. Wang, D. Weiss, M. Wilinski, W. Xu, A. Zaltsman BNL, Upton, Long Island, New York, USA S.A. Belomestnykh, I. Ben-Zvi, J. Dai, L.R. Hammons, V. Litvinenko, V. Ptitsyn Stony Brook University, Stony Brook, USA
	Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE and DOE grant at Stony Brook, DE-SC0005713. An ampere class 20 MeV superconducting Energy Recovery Linac (ERL) is presently under commissioning at Brookhaven National Laboratory (BNL). This facility enables testing of concepts relevant for high-energy coherent electron cooling, electron-ion colliders, and high repetition rate Free-Electron Lasers. The ERL will be capable of providing electron beams with sufficient quality to produce high repetition rate THz and X-ray radiation. When completed the SRF photoinjector will provide 2 MeV energy and 300 mA average beam current. The injector for the R&D ERL was installed in 2012, this includes a 704MHz SRF gun* with multi-alkali photocathode, cryo-system upgrade and a novel emittance preservation zigzag-like low energy merger system. We describe the design and major components of the R&D ERL injector then report the first experimental results and experiences learned in the first stage of beam commissioning of the BNL R&D ERL. * Wencan Xu et al., “Commissioning SRF gun for the R&D ERL at BNL”, IPAC2013 proceedings, WEPWO085.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI064
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TUPRO077	AGS Snake Stories	1220
	F. Méot, Y. Dutheil, R.C. Gupta, H. Huang, N. Tsoupas BNL, Upton, Long Island, New York, USA J. Takano J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. This contribution re-visits fields, particle motion, and spin precession in the AGS helical polarization snakes. The work was undertaken in preparation of orbit and spin modeling for future polarized proton and helion runs at RHIC. The investigations include re-computation of 3-D OPERA field maps of the helical snakes and particle and spin tracking. There is a series of sub-products of this study, amongst others, the appropriate settings of the AGS cold snake when changing its strength, cold snake settings for polarized helion programs, non-linear coupling in the AGS, the transport of the stable polarization axis from the AGS to RHIC injection kickers, and in addition, a series of high accuracy 3-D field maps have been produced, in view of long-term tracking in the AGS for beam and polarization transmission studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO077
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WEPRI101	Iron Shims outside the Helium Vessel to Adjust Field Quality at High Fields	2734
	R.C. Gupta, M. Anerella, J.P. Cozzolino, A.K. Jain, J.F. Muratore, P. Wanderer BNL, Upton, Long Island, New York, USA
	Funding: This work is supported by the U.S. Department of Energy under Contract No. DE¬AC02-98CH10886. This paper describes the development and demonstration of a novel technique of adjusting measured field quality at the design field in superconducting magnets. The technique is based on placing iron shims of variable stack thicknesses, variable width and/or variable length on the outer surface of the stainless steel shell at strategic locations. Since the shims are placed outside the helium vessel, adjustments can be made without involving major operations such as opening the helium vessel. It is a simple and economical technique which is suitable for long magnets with a fast turn-around. This allows one to reduce field errors well beyond the normal construction errors. The technique has recently been successfully applied in two 3.8 T, 80 mm aperture, 9.45 m long dipoles. These magnets were built at Brookhaven National Laboratory (BNL) for the APUL project (Accelerator Project to Upgrade the LHC) as a part of US contribution to LHC. The paper will present the design, measurement and adaptation of this technique which, when used in combination with the coil shims, produced near zero sextupole harmonic at high fields and small harmonics throughout the range of operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI101
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WEPRI102	Conceptual Magnetic Design of the Large Aperture D2 Dipole for LHC Upgrade	2737
	R.C. Gupta BNL, Upton, Long Island, New York, USA
	Funding: This work is supported by the U.S. Department of Energy under Contract No. DE¬AC02-98CH10886. CERN has proposed the High Luminosity upgrade of the Large Hadron Collider (HL-LHC) as an upgrade to the Large Hadron Collider (LHC). As a part of this proposal, the aperture of twin aperture D2 dipole is increased from the present 80 mm to 10⁵ mm without increasing the size of cryostat. This creates a significant challenge in managing saturation induced harmonics and the leakage field, particularly since the field in the two apertures is in the same direction. In addition, small spacing between the two apertures creates significant cross-talk harmonics as well. The expected harmonics based on an initial design were rather large and limited the beam dynamics performance of the machine. This paper will present a series of conceptual magnetic designs which reduce the values of key harmonics by a large amount with expected field errors now comparable to those in most superconducting accelerator magnets.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI102
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Paper

Title

Page

First Test Results from SRF Photoinjector for the R&D ERL at BNL

748

D. Kayran, Z. Altinbas, D.R. Beavis, S.A. Belomestnykh, I. Ben-Zvi, J. Dai, S. Deonarine, D.M. Gassner, R.C. Gupta, H. Hahn, L.R. Hammons, C. Ho, J.P. Jamilkowski, P. Kankiya, N. Laloudakis, R.F. Lambiase, V. Litvinenko, G.J. Mahler, L. Masi, G.T. McIntyre, T.A. Miller, D. Phillips, V. Ptitsyn, T. Rao, T. Seda, B. Sheehy, K.S. Smith, A.N. Steszyn, T.N. Tallerico, R. Than, R.J. Todd, E. Wang, D. Weiss, M. Wilinski, W. Xu, A. Zaltsman
BNL, Upton, Long Island, New York, USA
S.A. Belomestnykh, I. Ben-Zvi, J. Dai, L.R. Hammons, V. Litvinenko, V. Ptitsyn
Stony Brook University, Stony Brook, USA

Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE and DOE grant at Stony Brook, DE-SC0005713.
An ampere class 20 MeV superconducting Energy Recovery Linac (ERL) is presently under commissioning at Brookhaven National Laboratory (BNL). This facility enables testing of concepts relevant for high-energy coherent electron cooling, electron-ion colliders, and high repetition rate Free-Electron Lasers. The ERL will be capable of providing electron beams with sufficient quality to produce high repetition rate THz and X-ray radiation. When completed the SRF photoinjector will provide 2 MeV energy and 300 mA average beam current. The injector for the R&D ERL was installed in 2012, this includes a 704MHz SRF gun* with multi-alkali photocathode, cryo-system upgrade and a novel emittance preservation zigzag-like low energy merger system. We describe the design and major components of the R&D ERL injector then report the first experimental results and experiences learned in the first stage of beam commissioning of the BNL R&D ERL.
* Wencan Xu et al., “Commissioning SRF gun for the R&D ERL at BNL”, IPAC2013 proceedings, WEPWO085.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI064

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

TUPRO077

AGS Snake Stories

1220

F. Méot, Y. Dutheil, R.C. Gupta, H. Huang, N. Tsoupas
BNL, Upton, Long Island, New York, USA
J. Takano
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
This contribution re-visits fields, particle motion, and spin precession in the AGS helical polarization snakes. The work was undertaken in preparation of orbit and spin modeling for future polarized proton and helion runs at RHIC. The investigations include re-computation of 3-D OPERA field maps of the helical snakes and particle and spin tracking. There is a series of sub-products of this study, amongst others, the appropriate settings of the AGS cold snake when changing its strength, cold snake settings for polarized helion programs, non-linear coupling in the AGS, the transport of the stable polarization axis from the AGS to RHIC injection kickers, and in addition, a series of high accuracy 3-D field maps have been produced, in view of long-term tracking in the AGS for beam and polarization transmission studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO077

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

WEPRI101

Iron Shims outside the Helium Vessel to Adjust Field Quality at High Fields

2734

R.C. Gupta, M. Anerella, J.P. Cozzolino, A.K. Jain, J.F. Muratore, P. Wanderer
BNL, Upton, Long Island, New York, USA

Funding: This work is supported by the U.S. Department of Energy under Contract No. DE¬AC02-98CH10886.
This paper describes the development and demonstration of a novel technique of adjusting measured field quality at the design field in superconducting magnets. The technique is based on placing iron shims of variable stack thicknesses, variable width and/or variable length on the outer surface of the stainless steel shell at strategic locations. Since the shims are placed outside the helium vessel, adjustments can be made without involving major operations such as opening the helium vessel. It is a simple and economical technique which is suitable for long magnets with a fast turn-around. This allows one to reduce field errors well beyond the normal construction errors. The technique has recently been successfully applied in two 3.8 T, 80 mm aperture, 9.45 m long dipoles. These magnets were built at Brookhaven National Laboratory (BNL) for the APUL project (Accelerator Project to Upgrade the LHC) as a part of US contribution to LHC. The paper will present the design, measurement and adaptation of this technique which, when used in combination with the coil shims, produced near zero sextupole harmonic at high fields and small harmonics throughout the range of operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI101

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

WEPRI102

Conceptual Magnetic Design of the Large Aperture D2 Dipole for LHC Upgrade

2737

R.C. Gupta
BNL, Upton, Long Island, New York, USA

Funding: This work is supported by the U.S. Department of Energy under Contract No. DE¬AC02-98CH10886.
CERN has proposed the High Luminosity upgrade of the Large Hadron Collider (HL-LHC) as an upgrade to the Large Hadron Collider (LHC). As a part of this proposal, the aperture of twin aperture D2 dipole is increased from the present 80 mm to 10⁵ mm without increasing the size of cryostat. This creates a significant challenge in managing saturation induced harmonics and the leakage field, particularly since the field in the two apertures is in the same direction. In addition, small spacing between the two apertures creates significant cross-talk harmonics as well. The expected harmonics based on an initial design were rather large and limited the beam dynamics performance of the machine. This paper will present a series of conceptual magnetic designs which reduce the values of key harmonics by a large amount with expected field errors now comparable to those in most superconducting accelerator magnets.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI102

Export •

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