2011 Particle Accelerator Conference - List of Authors (Zhang, Y.)

Paper	Title	Page
TUP220	Cryogenic Sub-System for the 56 MHz SRF Storage Cavity for RHIC	1226
	Y. Huang, D.L. Lederle, L. Masi, P. Orfin, T.N. Tallerico, P. Talty, R. Than, Y. 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 56 MHz Superconducting RF Cavity is being constructed for the RHIC collider. This cavity is a quarter wave resonator that will be operated at 4.4K. The cavity requires an extreme quiet environment to maintain its operating frequency. The cavity besides being engineered for a mechanically quiet system, also requires a quiet cryogenic system. Liquid helium is taken from RHIC's main helium 3.5 atm, 4.9K supply header to supply this sub-system and the boil-off is return to a separate local compressor system nearby. To acoustically separate the cryogenics' delivery and return lines, a condenser/boiler heat exchanger is used to re-liquefy the helium vapor generated by the cavity. A system description and operating parameters is given about the cryogen delivery sub-system.

TUP223	Cryogenic System for the Energy Recovery Linac and Vertical Test Facility at BNL	1235
	R. Than, D.L. Lederle, L. Masi, P. Orfin, R. Porqueddu, V. Soria, T.N. Tallerico, P. Talty, Y. 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 small cryogenic system and warm helium vacuum pumping system provides cooling to the Energy Recovery Linac's (ERL) cryomodules, a 5-cell cavity and an SRF gun, and a large Vertical Test Dewar. The system consist of a model 1660S PSI (KPS) plant, a 4000 liter storage dewar, subcooler, wet expander, 50 g/s main helium compressor and 170 m³ storage tank. A system description and operating plan is given of the cryogenic plant and cryomodules

WEP082	Crab Crossing Consideration for MEIC	1627
	S. Ahmed, Y.S. Derbenev, G.A. Krafft, Y. Zhang JLAB, Newport News, Virginia, USA A. Castilla, J.R. Delayen, S.D. Silva ODU, Norfolk, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Crab crossing of colliding electron and ion beams is essential for accommodating the ultra high bunch repetition frequency in the conceptual design of MEIC – a high luminosity polarized electron-ion collider at Jefferson Lab. The scheme eliminates parasitic beam-beam interactions and avoids luminosity reduction by restoring head-on collisions at interaction points. In this paper, we report simulation studies of beam dynamics with crab cavities for MEIC design. The detailed study involves full 3-D simulations of particle tracking through the various configurations of crab cavities for evaluating the performance. To gain insight, beam and RF dominated fields with other parametric studies will be presented in the paper.

WEP206	An Accumulator/Pre-Booster for the Medium-Energy Electron Ion Collider at JLab	1873
	B. Erdelyi, S. Abeyratne Northern Illinois University, DeKalb, Illinois, USA Y.S. Derbenev, G.A. Krafft, Y. Zhang JLAB, Newport News, Virginia, USA S.L. Manikonda, P.N. Ostroumov ANL, Argonne, USA
	Future nuclear physics facilities such as the proposed electron ion collider (MEIC) will need to achieve record high luminosities in order to maximize discovery potential. Among the necessary ingredients is the ability to generate, accumulate, accelerate, and store high current ion beams from protons to lead ions. One of the main components of this ion accelerator complex for MEIC chain is the accumulator that also doubles as a pre-booster, which takes 200 MeV protons from a superconducting linear accelerator, accumulates on the order of 1A beam, and boosts its energy to 3GeV, before extraction to the next accelerator in the chain, the large booster. This paper describes its design concepts, and summarizes some preliminary results, including linear optics, space charge dynamics, and spin polarization resonance analysis.

THP093	Design Status of MEIC at JLab	2306
	Y. Zhang, S. Ahmed, S.A. Bogacz, P. Chevtsov, Y.S. Derbenev, A. Hutton, G.A. Krafft, R. Li, F. Marhauser, V.S. Morozov, F.C. Pilat, R.A. Rimmer, Y. Roblin, T. Satogata, M. Spata, B. Terzić, M.G. Tiefenback, H. Wang, B.C. Yunn JLAB, Newport News, Virginia, USA S. Abeyratne, B. Erdelyi Northern Illinois University, DeKalb, Illinois, USA D.P. Barber Cockcroft Institute, Warrington, Cheshire, United Kingdom A.M. Kondratenko GOO Zaryad, Novosibirsk, Russia S.L. Manikonda, P.N. Ostroumov ANL, Argonne, USA H. K. Sayed ODU, Norfolk, Virginia, USA M.K. Sullivan SLAC, Menlo Park, California, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. An electron-ion collider (MEIC) is envisioned as the primary future of the JLab nuclear science program beyond the 12 GeV upgraded CEBAF. The present MEIC design selects a ring-ring collider option and covers a CM energy range up to 51 GeV for both polarized light ions and un-polarized heavy ions, while higher CM energies could be reached by a future upgrade. The MEIC stored colliding ion beams, which will be generated, accumulated and accelerated in a green field ion complex, are designed to match the stored electron beam injected at full energy from the CEBAF in terms of emittance, bunch length, charge and repetition frequency. This design strategy ensures a high luminosity above 10³⁴ s⁻¹cm^-2. A unique figure-8 shape collider ring is adopted for advantages of preserving ion polarization during acceleration and accommodation of a polarized deuteron beam for collisions. Our recent effort has been focused on completing this conceptual design as well as design optimization of major components. Significant progress has also been made in accelerator R&D including chromatic correction and dynamical aperture, beam-beam, high energy electron cooling and polarization tracking.

TUP025	Two Wien Filter Spin Flipper	862
	J.M. Grames, P.A. Adderley, J. F. Benesch, J. Clark, J. Hansknecht, R. Kazimi, D. Machie, M. Poelker, M.L. Stutzman, R. Suleiman, Y. Zhang JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. A new 4pi spin manipulator composed of two Wien filters oriented orthogonally and separated by two solenoids has been installed at the CEBAF/Jefferson Lab photoinjector. The new spin manipulator is used to precisely set the electron spin direction at an experiment in any direction (in or out of plane of the accelerator) and provides the means to reverse, or flip, the helicity of the electron beam on a daily basis. This reversal is being employed to suppress systematic false asymmetries that can jeopardize challenging parity violation experiments that strive to measure increasingly small physics asymmetries [,,*]. The spin manipulator is part of the ultra-high vacuum polarized electron source beam line and has been successfully operated with 100keV and 130keV electron beam at high current (>100 microAmps). A unique feature of the device is that spin-flipping requires only the polarity of one solenoid magnet be changed. Performance characteristics of the Two Wien Filter Spin Flipper will be summarized. http://hallaweb.jlab.org/parity/prex/ http://www.jlab.org/qweak/ * http://hallaweb.jlab.org/12GeV/Moller/

WEP041	Weak Resonances Induced by Nonlinear Multipoles in a Quadrupole Doublet Lattice	1570
	Y. Zhang, J. G. Wang ORNL, Oak Ridge, Tennessee, USA
	Funding: This submission was sponsored by a contractor of the United States Government under contract DE-AC05-00OR22725 with the United States Department of Energy. In this paper we report the effects on beam dynamics from two intrinsic multipole components of a quadrupole magnet – dodecapole and psedu-octupole, in a quadrupole doublet lattice. Weak resonances at transverse phase advances 60°; and 90°; per cell, which may contribute to halo formation and beam loss in a linac, are shown from multi-particle tracking simulations. Although the net effect of the psedu-octupole component alone is very small due to substantial cancellations within the same magnet, its existence may significantly enhance the weak resonances which are induced by the dodecapole component of quadrupole magnets. The combined contributions of these two magnetic field components may not be simply linear-scaled because of the extreme nonlinear nature.

Paper

Title

Page

Cryogenic Sub-System for the 56 MHz SRF Storage Cavity for RHIC

1226

Y. Huang, D.L. Lederle, L. Masi, P. Orfin, T.N. Tallerico, P. Talty, R. Than, Y. 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 56 MHz Superconducting RF Cavity is being constructed for the RHIC collider. This cavity is a quarter wave resonator that will be operated at 4.4K. The cavity requires an extreme quiet environment to maintain its operating frequency. The cavity besides being engineered for a mechanically quiet system, also requires a quiet cryogenic system. Liquid helium is taken from RHIC's main helium 3.5 atm, 4.9K supply header to supply this sub-system and the boil-off is return to a separate local compressor system nearby. To acoustically separate the cryogenics' delivery and return lines, a condenser/boiler heat exchanger is used to re-liquefy the helium vapor generated by the cavity. A system description and operating parameters is given about the cryogen delivery sub-system.

TUP223

Cryogenic System for the Energy Recovery Linac and Vertical Test Facility at BNL

1235

R. Than, D.L. Lederle, L. Masi, P. Orfin, R. Porqueddu, V. Soria, T.N. Tallerico, P. Talty, Y. 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 small cryogenic system and warm helium vacuum pumping system provides cooling to the Energy Recovery Linac's (ERL) cryomodules, a 5-cell cavity and an SRF gun, and a large Vertical Test Dewar. The system consist of a model 1660S PSI (KPS) plant, a 4000 liter storage dewar, subcooler, wet expander, 50 g/s main helium compressor and 170 m³ storage tank. A system description and operating plan is given of the cryogenic plant and cryomodules

WEP082

Crab Crossing Consideration for MEIC

1627

S. Ahmed, Y.S. Derbenev, G.A. Krafft, Y. Zhang
JLAB, Newport News, Virginia, USA
A. Castilla, J.R. Delayen, S.D. Silva
ODU, Norfolk, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Crab crossing of colliding electron and ion beams is essential for accommodating the ultra high bunch repetition frequency in the conceptual design of MEIC – a high luminosity polarized electron-ion collider at Jefferson Lab. The scheme eliminates parasitic beam-beam interactions and avoids luminosity reduction by restoring head-on collisions at interaction points. In this paper, we report simulation studies of beam dynamics with crab cavities for MEIC design. The detailed study involves full 3-D simulations of particle tracking through the various configurations of crab cavities for evaluating the performance. To gain insight, beam and RF dominated fields with other parametric studies will be presented in the paper.

WEP206

An Accumulator/Pre-Booster for the Medium-Energy Electron Ion Collider at JLab

1873

B. Erdelyi, S. Abeyratne
Northern Illinois University, DeKalb, Illinois, USA
Y.S. Derbenev, G.A. Krafft, Y. Zhang
JLAB, Newport News, Virginia, USA
S.L. Manikonda, P.N. Ostroumov
ANL, Argonne, USA

Future nuclear physics facilities such as the proposed electron ion collider (MEIC) will need to achieve record high luminosities in order to maximize discovery potential. Among the necessary ingredients is the ability to generate, accumulate, accelerate, and store high current ion beams from protons to lead ions. One of the main components of this ion accelerator complex for MEIC chain is the accumulator that also doubles as a pre-booster, which takes 200 MeV protons from a superconducting linear accelerator, accumulates on the order of 1A beam, and boosts its energy to 3GeV, before extraction to the next accelerator in the chain, the large booster. This paper describes its design concepts, and summarizes some preliminary results, including linear optics, space charge dynamics, and spin polarization resonance analysis.

THP093

Design Status of MEIC at JLab

2306

Y. Zhang, S. Ahmed, S.A. Bogacz, P. Chevtsov, Y.S. Derbenev, A. Hutton, G.A. Krafft, R. Li, F. Marhauser, V.S. Morozov, F.C. Pilat, R.A. Rimmer, Y. Roblin, T. Satogata, M. Spata, B. Terzić, M.G. Tiefenback, H. Wang, B.C. Yunn
JLAB, Newport News, Virginia, USA
S. Abeyratne, B. Erdelyi
Northern Illinois University, DeKalb, Illinois, USA
D.P. Barber
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A.M. Kondratenko
GOO Zaryad, Novosibirsk, Russia
S.L. Manikonda, P.N. Ostroumov
ANL, Argonne, USA
H. K. Sayed
ODU, Norfolk, Virginia, USA
M.K. Sullivan
SLAC, Menlo Park, California, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
An electron-ion collider (MEIC) is envisioned as the primary future of the JLab nuclear science program beyond the 12 GeV upgraded CEBAF. The present MEIC design selects a ring-ring collider option and covers a CM energy range up to 51 GeV for both polarized light ions and un-polarized heavy ions, while higher CM energies could be reached by a future upgrade. The MEIC stored colliding ion beams, which will be generated, accumulated and accelerated in a green field ion complex, are designed to match the stored electron beam injected at full energy from the CEBAF in terms of emittance, bunch length, charge and repetition frequency. This design strategy ensures a high luminosity above 10³⁴ s⁻¹cm^-2. A unique figure-8 shape collider ring is adopted for advantages of preserving ion polarization during acceleration and accommodation of a polarized deuteron beam for collisions. Our recent effort has been focused on completing this conceptual design as well as design optimization of major components. Significant progress has also been made in accelerator R&D including chromatic correction and dynamical aperture, beam-beam, high energy electron cooling and polarization tracking.

TUP025

Two Wien Filter Spin Flipper

862

J.M. Grames, P.A. Adderley, J. F. Benesch, J. Clark, J. Hansknecht, R. Kazimi, D. Machie, M. Poelker, M.L. Stutzman, R. Suleiman, Y. Zhang
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A new 4pi spin manipulator composed of two Wien filters oriented orthogonally and separated by two solenoids has been installed at the CEBAF/Jefferson Lab photoinjector. The new spin manipulator is used to precisely set the electron spin direction at an experiment in any direction (in or out of plane of the accelerator) and provides the means to reverse, or flip, the helicity of the electron beam on a daily basis. This reversal is being employed to suppress systematic false asymmetries that can jeopardize challenging parity violation experiments that strive to measure increasingly small physics asymmetries [*,**,***]. The spin manipulator is part of the ultra-high vacuum polarized electron source beam line and has been successfully operated with 100keV and 130keV electron beam at high current (>100 microAmps). A unique feature of the device is that spin-flipping requires only the polarity of one solenoid magnet be changed. Performance characteristics of the Two Wien Filter Spin Flipper will be summarized.
* http://hallaweb.jlab.org/parity/prex/
** http://www.jlab.org/qweak/
*** http://hallaweb.jlab.org/12GeV/Moller/

WEP041

Weak Resonances Induced by Nonlinear Multipoles in a Quadrupole Doublet Lattice

1570

Y. Zhang, J. G. Wang
ORNL, Oak Ridge, Tennessee, USA

Funding: This submission was sponsored by a contractor of the United States Government under contract DE-AC05-00OR22725 with the United States Department of Energy.
In this paper we report the effects on beam dynamics from two intrinsic multipole components of a quadrupole magnet – dodecapole and psedu-octupole, in a quadrupole doublet lattice. Weak resonances at transverse phase advances 60°; and 90°; per cell, which may contribute to halo formation and beam loss in a linac, are shown from multi-particle tracking simulations. Although the net effect of the psedu-octupole component alone is very small due to substantial cancellations within the same magnet, its existence may significantly enhance the weak resonances which are induced by the dodecapole component of quadrupole magnets. The combined contributions of these two magnetic field components may not be simply linear-scaled because of the extreme nonlinear nature.