IPAC2015 - List of Authors (Kazimi, R.)

Paper	Title	Page
TUPMA020	PEPPo: Using a Polarized Electron Beam to Produce Polarized Positrons	1878
	A.H. Adeyemi, P.L. Gueye Hampton University, Hampton, Virginia, USA P.A. Adderley, M.M. Ali, H. Areti, J. F. Benesch, L.S. Cardman, J. Clark, S. Covert, C. Cuevas, A. Freyberger, S. Golge, J.M. Grames, P.L. Gueye, J. Hansknecht, P.L. Harrell, C. Hyde, R. Kazimi, Y. Kim, D. Machie, K.L. Mahoney, R.R. Mammei, J.L. McCarter, M.D. McCaughan, M. Poelker, M.L. Stutzman, R. Suleiman, C.-Y. Tsai, D.L. Turner, Y.W. Wang JLab, Newport News, Virginia, USA M.A. Baylac, E. Froidefond, M. Marton, J-F. Muraz, J-S. Real, E. J-M. Voutier LPSC, Grenoble Cedex, France P. Cole, D. Dale, T.A. Forest ISU, Pocatello, Idaho, USA O. Dadoun, A. Variola LAL, Orsay, France D. Dale, Y. Kim IAC, Pocatello, Idaho, USA EF. Fanchini INFN Genova, Genova, Italy S. Golge NCCU, , North Carolina, USA S. Golge, C. Hyde ODU, Norfolk, Virginia, USA J.L. McCarter UVa, Charlottesville, Virginia, USA C.-Y. Tsai Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA A. Variola IN2P3-CNRS, Orsay, France
	Polarized positron beams have been identified as either an essential or a significant ingredient for the experimental program of both the present and next generation of lepton accelerators (JLab, Super KEK B, ILC, CLIC). An experiment demonstrating a new method for producing polarized positrons has been performed at the Continuous Electron Beam Accelerator Facility at Jefferson Lab. The PEPPo (Polarized Electrons for Polarized Positrons) concept relies on the production of polarized e⁻/e⁺ pairs from the bremsstrahlung radiation of a longitudinally polarized electron beam interacting within a high Z conversion target. PEPPo demonstrated the effective transfer of spin-polarization of an 8.2 MeV/c polarized (P~85%) electron beam to positrons produced in varying thickness tungsten production targets, and collected and measured in the range of 3.1 to 6.2 MeV/c. In comparison to other methods this technique reveals a new pathway for producing either high energy or thermal polarized positron beams using a relatively low polarized electron beam energy (~10MeV) .This presentation will describe the PEPPo concept, the motivations of the experiment and high positron polarization achieved.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA020
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TUPMA035	Control of Synchrotron Radiation Effects during Recirculation	1913
	D. Douglas, S.V. Benson, A.S. Hofler, R. Kazimi, R. Li, Y. Roblin, C. Tennant JLab, Newport News, Virginia, USA G.A. Krafft, B. Terzić ODU, Norfolk, Virginia, USA C.-Y. Tsai Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. Numerous proposals invoke recirculation and/or energy recovery for cost-performance optimization. These often encounter challenges with the beam-quality-degrading effects of incoherent and coherent synchrotron radiation (ISR and CSR). We describe a means of controlling of this degradation. The approach utilizes results by diMitri et al. , and invokes behavior observed during simulations of the recirculation process. The method is based on the use of periodically isochronous 2nd-order achromats; this not only insures that the conditions for the suppression of CSR-driven emittance growth are met, it also suppresses micro-bunching gain over a broad range of parameter space . Details of specific designs will be presented, and a reference to an analysis of micro-bunching effects provided. A planned test of the CSR suppression mechanism in CEBAF will be described. S. diMitri et al., Phys. Rev. Lett. 110, 014801, 2 January 2013. *C.Y. Tsai et al., these proceedings.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA035
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TUPMA037	Commissioning of the 123 MeV Injector for 12 GeV CEBAF	1920
	Y.W. Wang, A.S. Hofler, R. Kazimi JLab, Newport News, Virginia, USA
	The injector energy needed to be raised from 67.5 MeV to 123 MeV to meet the energy requirement of the CEBAF 12 GeV upgrade. The ratio of the injector energy to the linac energy must remain 0.11284 at all times. Consequently, the injector was partially upgraded. The early injector, transport and acceleration from 130 keV to 6 MeV, is unchanged, but the downstream boost from 6 MeV to the final 123 MeV energy drove several changes. One of the two original CEBAF 25 MeV type cryomodules in the injector was upgraded to a 100 MeV capable one to provide more energy. Some trim magnets at the end of the injector were upgraded to compensate for the higher energy. The chicane region was expanded, and the full energy injector spectrometer was relocated to make room for the newly added Hall D line. Experience from the 6 GeV era indicated that the stray fields from the higher energy beam transport recombiners near the injection chicane adversely affect the injector orbit, so a study to understand and mitigate stray fields from the transport arc box supplies upgraded for 12 GeV led to shielding modifications for the beamline in the chicane region.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA037
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Paper

Title

Page

PEPPo: Using a Polarized Electron Beam to Produce Polarized Positrons

1878

A.H. Adeyemi, P.L. Gueye
Hampton University, Hampton, Virginia, USA
P.A. Adderley, M.M. Ali, H. Areti, J. F. Benesch, L.S. Cardman, J. Clark, S. Covert, C. Cuevas, A. Freyberger, S. Golge, J.M. Grames, P.L. Gueye, J. Hansknecht, P.L. Harrell, C. Hyde, R. Kazimi, Y. Kim, D. Machie, K.L. Mahoney, R.R. Mammei, J.L. McCarter, M.D. McCaughan, M. Poelker, M.L. Stutzman, R. Suleiman, C.-Y. Tsai, D.L. Turner, Y.W. Wang
JLab, Newport News, Virginia, USA
M.A. Baylac, E. Froidefond, M. Marton, J-F. Muraz, J-S. Real, E. J-M. Voutier
LPSC, Grenoble Cedex, France
P. Cole, D. Dale, T.A. Forest
ISU, Pocatello, Idaho, USA
O. Dadoun, A. Variola
LAL, Orsay, France
D. Dale, Y. Kim
IAC, Pocatello, Idaho, USA
EF. Fanchini
INFN Genova, Genova, Italy
S. Golge
NCCU, , North Carolina, USA
S. Golge, C. Hyde
ODU, Norfolk, Virginia, USA
J.L. McCarter
UVa, Charlottesville, Virginia, USA
C.-Y. Tsai
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
A. Variola
IN2P3-CNRS, Orsay, France

Polarized positron beams have been identified as either an essential or a significant ingredient for the experimental program of both the present and next generation of lepton accelerators (JLab, Super KEK B, ILC, CLIC). An experiment demonstrating a new method for producing polarized positrons has been performed at the Continuous Electron Beam Accelerator Facility at Jefferson Lab. The PEPPo (Polarized Electrons for Polarized Positrons) concept relies on the production of polarized e⁻/e⁺ pairs from the bremsstrahlung radiation of a longitudinally polarized electron beam interacting within a high Z conversion target. PEPPo demonstrated the effective transfer of spin-polarization of an 8.2 MeV/c polarized (P~85%) electron beam to positrons produced in varying thickness tungsten production targets, and collected and measured in the range of 3.1 to 6.2 MeV/c. In comparison to other methods this technique reveals a new pathway for producing either high energy or thermal polarized positron beams using a relatively low polarized electron beam energy (~10MeV) .This presentation will describe the PEPPo concept, the motivations of the experiment and high positron polarization achieved.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA020

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TUPMA035

Control of Synchrotron Radiation Effects during Recirculation

1913

D. Douglas, S.V. Benson, A.S. Hofler, R. Kazimi, R. Li, Y. Roblin, C. Tennant
JLab, Newport News, Virginia, USA
G.A. Krafft, B. Terzić
ODU, Norfolk, Virginia, USA
C.-Y. Tsai
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Numerous proposals invoke recirculation and/or energy recovery for cost-performance optimization. These often encounter challenges with the beam-quality-degrading effects of incoherent and coherent synchrotron radiation (ISR and CSR). We describe a means of controlling of this degradation. The approach utilizes results by diMitri et al. *, and invokes behavior observed during simulations of the recirculation process. The method is based on the use of periodically isochronous 2nd-order achromats; this not only insures that the conditions for the suppression of CSR-driven emittance growth are met*, it also suppresses micro-bunching gain over a broad range of parameter space **. Details of specific designs will be presented, and a reference to an analysis of micro-bunching effects ** provided. A planned test of the CSR suppression mechanism in CEBAF will be described.
*S. diMitri et al., Phys. Rev. Lett. 110, 014801, 2 January 2013.
**C.Y. Tsai et al., these proceedings.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA035

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TUPMA037

Commissioning of the 123 MeV Injector for 12 GeV CEBAF

1920

Y.W. Wang, A.S. Hofler, R. Kazimi
JLab, Newport News, Virginia, USA

The injector energy needed to be raised from 67.5 MeV to 123 MeV to meet the energy requirement of the CEBAF 12 GeV upgrade. The ratio of the injector energy to the linac energy must remain 0.11284 at all times. Consequently, the injector was partially upgraded. The early injector, transport and acceleration from 130 keV to 6 MeV, is unchanged, but the downstream boost from 6 MeV to the final 123 MeV energy drove several changes. One of the two original CEBAF 25 MeV type cryomodules in the injector was upgraded to a 100 MeV capable one to provide more energy. Some trim magnets at the end of the injector were upgraded to compensate for the higher energy. The chicane region was expanded, and the full energy injector spectrometer was relocated to make room for the newly added Hall D line. Experience from the 6 GeV era indicated that the stray fields from the higher energy beam transport recombiners near the injection chicane adversely affect the injector orbit, so a study to understand and mitigate stray fields from the transport arc box supplies upgraded for 12 GeV led to shielding modifications for the beamline in the chicane region.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA037

Export •

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