Geometry Optimization for a Quadrupole Resonator at Jefferson Lab

Abstract

The quadrupole resonator (QPR) is a sample characterization tool to measure the RF properties of superconducting materials using the calorime-try method at different temperatures, magnetic fields, and frequencies. Such resonators are cur-rently operating at CERN and HZB but suffer from Lorentz force detuning and modes overlap-ping, resulting in higher uncertainties in surface resistance measurement. Using the two CERN's QPR model iterations, the geometry was opti-mized via electromagnetic and mechanical simu-lations to eliminate these issues. The new QPR version was modelled for an increasing range of magnetic fields. The magnetic field is concentrat-ed at the center of the sample to reduce the un-certainty in surface resistance measurements sig-nificantly. This paper discusses the QPR geome-try optimization for the new version of QPR, which is now progressing toward fabrication.