HIGH VOLTAGE DESIGN AND EVALUATION OF WIEN FILTERS FOR THE CEBAF 200 keV INJECTOR UPGRADE

Conference · Sun Aug 01 00:00:00 EDT 2021

DOI:https://doi.org/10.18429/JACoW-IPAC2021-MOPAB324· OSTI ID:1824346

Palacios-Serrano, G. ^[1]; Adderley, P. ^[2]; Benesch, J. F. ^[2]; Bullard, D. B. ^[2]; Grames, J. M. ^[2]; Hernandez-Garcia, C. ^[2]; Hofler, A. S. ^[2]; Machie, D. ^[2]; Poelker, M. ^[2]; Stutzman, M. L. ^[2]; Suleiman, R.; Baumgart, H. ^[3]

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1. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States)
2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
3. Old Dominion Univ., Norfolk, VA (United States)

High-energy nuclear physics experiments at the Jefferson Lab Continuous Electron Beam Accelerator Facility (CEBAF) require highly spin-polarization electron beams, produced from strained super-lattice GaAs photocathodes, activated to negative electron affinity in a photogun operating at 130 kV dc. A pair of Wien filter spin rotators in the injector defines the orientation of the electron beam polarization at the end station target. An upgrade of the CEBAF injector to better support the upcoming MOLLER experiment requires increasing the electron beam energy to 200 keV, to reduce unwanted helicity correlated intensity and position systematics and provide precise control of the polarization orientation. Our contribution describes design, fabrication and testing of the high voltage system to upgrade the Wien spin rotator to be compatible with the 200 keV beam. This required Solidworks modeling, CST and Opera electro- and magnetostatic simulations, upgrading HV vacuum feedthroughs, and assembly techniques for improving electrode alignment. The electric and magnetic fields required by the Wien condition and the successful HV characterization under vacuum conditions are also presented.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1824346
• Report Number(s): JLAB-ACC-21-3388; DOE/OR/23177-5196
• Resource Relation: Conference: IPAC 2021, May 24-28, 2021, Brazil (virtual)
• Country of Publication: United States
• Language: English