A New cw-NMR Q-meter for Dynamically Polarized Targets for Particle Physics

TL;DR

This paper presents a modernized cw-NMR Q-meter designed for dynamic nuclear polarization targets, improving upon older Liverpool-style devices to enhance accuracy and reliability in polarization measurements.

Contribution

The authors developed a new cw-NMR Q-meter inspired by Liverpool designs, incorporating modern electronics for improved performance and adaptability for current particle physics experiments.

Findings

Achieved comparable electronic performance to traditional Liverpool Q-meters.

Enhanced device reliability and ease of use for polarization measurements.

Demonstrated successful application in DNP target polarization assessments.

Abstract

Polarized solid targets produced via Dynamic Nuclear Polarization rely on Continuous-Wave Nuclear Magnetism Resonance measurements to accurately determine the degree of polarization of bulk samples polarized to nearly 100%. Since the late 1970's phase sensitive detection methods have been utilized to observe the magnetization of a sample as a small change in inductance under RF excitation near the Larmor frequency of the nuclear species of interest, using a device known as a Q-meter. Liverpool Q-meters, produced in the UK in the 80's and 90's, have been the workhorse devices for these targets for decades, however their age and scarcity has meant new systems are needed. We describe a Q-meter system designed and built at Jefferson Lab in the Liverpool style to have comparable electronic performance with several improvements to update and adapt the devices for modern use.