Design and test of 704 MHz and 2.1 GHz normal conducting cavities for Low Energy RHIC electron Cooler

TL;DR

This paper presents the design and RF testing results of two normal conducting cavities, at 704 MHz and 2.1 GHz, developed for the Low Energy RHIC electron Cooler to improve beam quality.

Contribution

It introduces new cavity designs and provides RF test results for the 704 MHz and 2.1 GHz cavities used in LEReC, a novel approach for energy spread correction.

Findings

Successful RF testing of the 704 MHz cavity

Successful RF testing of the 2.1 GHz cavity

Demonstrated effectiveness for energy spread correction

Abstract

The Low Energy RHIC electron Cooler (LEReC) is currently under commissioning at BNL to improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon. The linac of LEReC consists of a DC photoemission gun, one 704 MHz superconducting radio frequency (SRF) booster cavity, and three normal conducting cavities. It is designed to deliver a 1.6 MeV to 2.6 MeV electron beam, with peak-to-peak momentum spread dp/p of less than 7e4. Two of the three normal conducting cavities will be used in LEReC for energy spread correction. A single-cell 704 MHz cavity for energy de-chirping and a three-cell 2.1 GHz third harmonic cavity for RF curvature correction. In this paper, we present the designs and RF test results of these two cavities.