Undergraduate Research at Jefferson Lab

Hodoscope Assembly for Jefferson Lab's BigBite Electron Spectrometer

Student: Nick Wade

School: Frostburg State University

Mentored By: Doug Higinbotham

Experimental tests for electric and magnetic nucleon form factors are necessary to prove if theoretical modeling techniques, such as lattice QCD, are accurate representations of the electromagnetic structure in a proton or neutron. Jefferson Lab Hall A proposes to measure the magnetic form factor of a neutron at several momentum transfer (Q2) values up to 18.0 (GeV/c)². To conduct these measurements precisely, the BigBite electron spectrometer in Hall A will require an upgrade. Our team is tasked with replacing the 13 hodoscope detectors between the pre- shower and shower calorimeters to a set of 90 detectors during this upgrade. This will lower the frequency of the hodoscope from 1 MHz to 100 kHz, making it easier to detect atomic particles. We achieve our goal by testing and assembling each detector individually, then installing them to the BigBite hodoscope. In the scope of our project, we show the scintillator detectors tested and installed on the hodoscope; however, the Hall A proposal extends beyond our installation. The result of the entire proposal will be the desired measurements of the neutron magnetic form factors which will, in turn, increase our understanding of the hadronic structure of neutrons. The refurbished BigBite electron spectrometer may also lead future experimental tests by Hall A for the distribution of quarks in nucleons.