BNL, Upton, Long Island, New York, USA
ESRF, Grenoble, France
A new type of electron-ion beam overlap monitor has been developed for the RHIC electron lenses. Low energy electrons acquire high energies in small impact parameter Coulomb scattering collisions with relativistic ions. Such electrons can traverse thin vacuum windows and be conveniently detected in air. Counting rates are maximized to optimize beam overlap. Operational experience with the electron backscattering detectors during the 2015 p-p RHIC run will be presented. Other possible real-time non-invasive beam-diagnostic applications of high energy Coulomb-scattered electrons will be briefly discussed.
Most of this material appears in an article by the same authors entitled "High energy Coulomb-scattered electrons for relativistic particle beam diagnostics", Phys. Rev. Accel. Beams 19, 041002 (2016)
BNL, Upton, Long Island, New York, USA
Non-magnetized bunched electron cooling of low-energy RHIC requires electron beam energy in range of 1.6-2.6 MeV, with average current up to 45 mA, very small energy spread, and low emittance [1]. A 400 kV DC gun equipped with photocathode and laser delivery system will serve as a source of high-quality electron beam. Acceleration will be achieved by an SRF 704 MHz booster cavity and other RF components that are scheduled to be operational in early 2018. The DC gun testing in its installed location in RHIC will start in early 2017. During this stage we plan to test the critical equipment in close to operation conditions: laser beam delivery system, cathode QE lifetime, DC gun, beam instrumentation, high power beam dump system, and controls. In this paper, we describe the gun test set up, major components, and parameters to be achieved and measured during the gun beam test.
[1] A. Fedotov. Bunched beam electron cooling for Low Energy RHIC operation. ICFA Beam Dynamics letter, No. 65, p. 22 (December 2014)
BNL, Upton, Long Island, New York, USA
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
The operation of LEReC is to provide an electron cooling to improve the luminosity of the RHIC heavy ion beam at lower energies in a range of 2.5-25 GeV/nucleon. The electron beam is generated in a DC Electron Gun (DC gun) designed and built by the Cornell High Energy Synchrotron Source Group. This DC gun will operate around the clock for at least two weeks without maintenance. This paper presents the design of a reliable cathode puck insertion system, which includes a multi-pucks storage device, a transfer mechanism, a puck insertion device, a vacuum/control system, and a transport scheme.