Compton polarimeter for Qweak Experiment at Jefferson Laboratory

Abstract

The Qweak experiment at Jefferson Lab aims to make the first precision measurement of the proton's weak charge, QP = 1 - 4 sin 2 9w at Q2 = 0.026GeV 2 . Given the precision goals in the Qweak experiment, the electron beam polarization must be known to an absolute uncertainty of 1%. A new Compton polarimeter has been built and installed in Hall C in order to make this important measurement. Compton polarimetry has been chosen for its ability to deliver continuous on-line measuremnts at high currents necessary for Qweak (up to 180pzA). In this thesis, we collected and analyzed electron beam polarization data using the Qweak Compton polarimeter. Currently, data from the Compton can already be used to calculate preliminary values of experimental physics asymmetries and also the electron beam polarization. These preliminary results are promising indications that Qweak will be able to meet its stated precision goals.