Sub-1% Electron Beam Polarimetry in Hall C at Jefferson Lab

Conference · Thu Oct 01 00:00:00 EDT 2015

OSTI ID:1969964

Gaskell, David ^[1]

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1. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

The electron beam polarization in experimental Hall C at Jefferson Lab has been measured with a total uncertainty of dP/P<0.7\% at a beam energy of ≈ 1~GeV. This was accomplished using two, high-precision electron beam polarimeters. The first device makes use of M\o ller scattering from atomic electrons polarized in a pure iron foil driven to magnetic saturation. The second uses polarized electron-photon (Compton) scattering from laser light stored in a low gain Fabry-Perot cavity. Data from both devices, as well as a direct comparison of the two will be shown. The polarization data that will be described were taken as part of the Qweak experiment in Hall C, which aimed to measure the polarization to better than 1\%. Future experiments at Jefferson Lab will require knowledge of the polarization to 0.4\% or better. In this talk, I will describe the lessons learned during the Qweak running and discuss prospects for improving the beam polarimetry precision to the 0.4\% level.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1969964
• Report Number(s): JLAB-PHY-15-2354; DOE/OR/23177-6048
• Country of Publication: United States
• Language: English