Undergraduate Research at Jefferson Lab

Study of the New Pulse NMR System for the Hall A Polarized Helium-3 Target

Student: Joseph Newton

School: Old Dominion University

Mentored By: Jian-Ping Chen

At Jefferson Lab, a Helium-3 target is used to study the neutron. The Helium-3 target is undergoing an upgrade to improve its polarization. Measuring it involved a new technique known as pulse Nuclear Magnetic Resonance (NMR). The purpose was to find noise and to compute the calibration constant. Pulse NMR calibration tests were performed by doing Adiabatic Fast Passage (AFP) NMR measurements followed by Pulse NMR measurements. Data analysis was done by fitting the pulse NMR signal from the oscilloscope and utilizing the Fourier Transform. Noise was analyzed in the fitting and the Fourier Transform. The values deviated between the pumping and target chambers of the cell when there was no convection but the values were closer when convection was induced. Noise was statistically significant. These results will enable the calculation of the polarization with pulse NMR. Also, the signal analysis provided insight into the influence of noise.