Experiment*

The very first experiment of the SBS (Super Bigbite Spectrometer) program in Hall-A of Jefferson Lab is the measurement of the magnetic form factor of the neutron (G_Mⁿ) using the ratio method which involves the detection of both neutron tagged, d(e,e'n) and proton tagged, d(e,e'p), quasi-elastic scattering from a deuteron target. The experiment explores several kinematic points ranging from 3.5 GeV²/c² to 13.5 GeV²/c² with beam energies going up to 9.91 GeV. The concept of the Super BigBite Spectrometer, which provides a large solid angle acceptance and the capability to operate at high luminosity, relies heavily on Gas Electron Multiplier (GEM) detector-based particle trackers. In the G_Mⁿ  experiment, GEM trackers are used in the BigBite Spectrometer (the electron arm) which will determine the q-vector of the scattering reaction. This is the very first time GEM detectors are used in high background rates of about 100 KHz/cm² in Jefferson lab. The parameters such as detector occupancy, gain/efficiency, and position resolution are of great interest to study. This talk will give a brief overview of the SBS - G_Mⁿ  experiment and elaborate more in detail about the performance of the UVA made GEM detectors during the experiment.