Introduction

The Hall A beam line is equipped with a Møller polarimeter, whose purpose is to measure the polarization of the electron beam delivered to the hall.

The Møller polarimeter consists of:

• a magnetized ferromagnetic foil used as a polarized electron target, placed 17.5 m upstream of the central pivot point of the Hall A High Resolution Spectrometers;

• a spectrometer consisting of three quadrupole magnets and a dipole magnet, used to deflect the electrons scattered in a certain kinematic range towards the Møller detector;

• a detector and its associated shielding house;
• a stand alone data acquisition system;
• off-line analysis software which helps to extract the beam polarization from the data immediately after the data are taken.

This document discusses the safe operation of the Møller polarimeter in the Hall A beam line.