Proton Polarimeter Calibration between 82 and 217 MeV

TL;DR

This paper presents new measurements of proton analyzing power in carbon across 82 to 217 MeV, introducing a refined parameterization that enhances calibration accuracy for polarized proton experiments.

Contribution

A new parameterization of the FPP proton-carbon analyzing power was developed, extending its validity to lower energies and larger angles, improving calibration methods.

Findings

Consistent measurements across different polarimeters.

Enhanced analyzing power calibration at low energies.

Improved figure of merit with larger angular range.

Abstract

The proton analyzing power in carbon has been measured for energies of 82 to 217 MeV and proton scattering angles of 5 to 41 degrees. The measurements were carried out using polarized protons from the elastic scattering H(pol. e, pol. p) reaction and the Focal Plane Polarimeter (FPP) in Hall A of Jefferson Lab. A new parameterization of the FPP p-C analyzing power was fit to the data, which is in good agreement with previous parameterizations and provides an extension to lower energies and larger angles. The main conclusions are that all polarimeters to date give consistent measurements of the carbon analyzing power, independently of the details of their construction and that measuring on a larger angular range significantly improves the polarimeter figure of merit at low energies.