[Jlab-seminars] Today's Physics Seminar: William Henry; Precision Møller Polarimetry in Hall A

[Stephanie Tysor]

Physics Seminar
William Henry
Temple University

Precision Møller Polarimetry in Hall A

Abstract:

Jefferson Lab's cutting-edge parity-violating electron scattering program has increasingly stringent requirements for systematic errors. Beam polarimetry is often one of the dominant systematic errors in these experiments. A new Møller Polarimeter in Hall A of Jefferson Lab (JLab) was installed in 2015 and has taken first measurements for a polarized scattering experiment. Upcoming parity violation experiments in Hall A include CREX, PREX-II, MOLLER and SOLID with the latter two requiring <0.5% precision on beam polarization measurements. The polarimeter measures the Møller scattering rates of the polarized electron beam incident upon an iron target placed in a saturating magnetic field. The spectrometer consists of four quadrupoles and one momentum selection dipole. The detector is designed to measure the scattered and knock out target electrons in coincidence. Beam polarization is extracted by constructing an asymmetry from the scattering rates when the incident electron spin is parallel and anti-parallel to the target electron spin. Initial data will be presented. Sources of systematic errors including target magnetization, analyzing power, and the Levchuk effect will be discussed.




Wednesday, January 16, 2019
2:30pm
CEBAF Center L102




Stephanie Tysor
Thomas Jefferson National Accelerator Facility
Physics Division
Hall A Administrative Assistant
(office)757-269-6005<callto:757-269-6005> (fax)757-269-5235<callto:757-269-5235>

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