Undergraduate Research at Jefferson Lab

Measurement of Jefferson Lab Beam Energy in Experimental Hall A During GMp

Student: Lucas Tracy

School: Old Dominion University

Mentored By: Bogdan Wojtsekhowski

The GpM experiment conducted throughout 2016 was designed to measure the elastic cross section of electron-proton scattering with an uncertainty of 1%. This was achieved by taking measurements at high momentum transfer, Q². In order to obtain this high level of accuracy a number of experimental parameters had to be controlled. Among these requirements was an accurate determination of the incident beam energy. A precise measurement of the incident beam energy utilizing the ARC method is presented. Here we show that utilizing the ARC method, a measurement of the incident beam energy with an accuracy of 0.1% can be achieved. These measurements allow for the determination of the electron-proton scattering cross section to such a desired accuracy.