Undergraduate Research at Jefferson Lab

Calibration of a Mott Polarimeter

Student: Valeria Ramirez-Cruz

School: Universidad Autónoma del Estado de Hidalgo

Mentored By: Carlos Hernandez-Garcia

The Upgrade Injector Test Facility (UITF) at Jefferson Lab will employ a Mott polarimeter to measure the spin-polarization of a low energy (<200 keV) electron beam. A GaAs electron source provides longitudinally polarized electrons which are then rotated transversely by a Wien filter before scattering from thin (<100 nm) gold foils into a pair of detectors counting their rate. A scattering rate asymmetry calculated between the detectors is directly proportional to the spin polarization. The purpose of this project is to calibrate the Mott polarimeter for each gold foil (called the effective Sherman function) to a well-known theoretical calculation when an electron scatters from an idealistic single gold atom.

[Watch the presentation on YouTube]