Low-Energy Run of Fermilab Electron Cooler's Beam Generation System

TL;DR

This study demonstrates that Fermilab's electron cooler beam generation system can reliably operate at low energy (1.6 MeV) for BNL's RHIC run, achieving stable recirculation and significant current without interruptions.

Contribution

It provides the first feasibility assessment of low-energy operation of Fermilab's electron cooler for BNL, showing stable beam recirculation at 1.6 MeV.

Findings

Stable beam recirculation at 1.6 MeV for all tested parameters

Achieved a beam current of 0.38 A with maximum cathode magnetic field

No unprovoked recirculation interruptions observed at low energy

Abstract

In the context of the evaluation of possibly using the Fermilab Electron Cooler for the proposed low-energy RHIC run at BNL, operating the cooler at 1.6 MeV electron beam energy was tested in a short beam line configuration. The main conclusion of this feasibility study is that the cooler's beam generation system is suitable for BNL needs. The beam recirculation was stable for all tested parameters. In particular, a beam current of 0.38 A was achieved with the cathode magnetic field up to the maximum value presently available of 250 G. The energy ripple was measured to be 40 eV. A striking difference with running the 4.3 MeV beam (nominal for operation at FNAL) is that no unprovoked beam recirculation interruptions were observed.