The Recycler Electron Cooler

TL;DR

The Recycler Electron Cooler at Fermilab was the first relativistic electron cooler, successfully developed and operated for antiproton cooling, overcoming significant technical challenges in electron beam parameters.

Contribution

This paper presents the design, development, and operational experience of the first relativistic electron cooler, including solutions to technical challenges and cooling performance results.

Findings

Successful operation at relativistic energy ({b3} = 9.5)

Overcame technical difficulties in electron beam parameters

Provided effective antiproton cooling in the Recycler ring

Abstract

The Recycler Electron cooler was the first (and so far, the only) cooler working at a relativistic energy ({\gamma} = 9.5). It was successfully developed in 1995-2004 and was in operation at Fermilab in 2005-2011, providing cooling of antiprotons in the Recycler ring. This paper describes the cooler, difficulties in achieving the required electron beam parameters and the ways to overcome them, cooling measurements, and details of operation.