Polarized Positrons at Jefferson Lab

TL;DR

This paper proposes a new method to produce polarized positrons at Jefferson Lab by transferring polarization from polarized electrons via bremsstrahlung and pair production, supported by GEANT4 simulations indicating up to 40% polarization.

Contribution

It introduces a novel low-energy approach for polarized positron production utilizing existing high polarization electron sources, with simulation validation.

Findings

Positron polarization up to 40% achievable.

Method leverages recent high polarization electron sources.

Simulation results support feasibility of the approach.

Abstract

A novel concept for producing polarized positrons at Jefferson Lab using the CEBAF polarized electron photo-injector is presented. This approach relies on the polarization transfer from low energy highly polarized electrons to positrons via bremsstrahlung followed by pair production in a conversion target. An experiment to test this concept is discussed on the basis of GEANT4 simulations. It is shown that this low energy approach, which benefits from recent advances in high current high polarization electron sources, can yield positron longitudinal polarization up to 40%.