BNL, Upton, Long Island, New York, USA
Stony Brook University, Stony Brook, USA
An ampere class 20 MeV superconducting Energy Recovery Linac (ERL) is presently under commissioning at Brookhaven National Laboratory (BNL) for testing of concepts relevant for high-energy coherent electron cooling and electron-ion colliders. The injector subsystems tests and installation were finished in fall 2013. The injector includes: SRF photoelectron gun with 1 MW amplifier, 10W green drive-laser system, multi-alkaline cathode deposition system, cathode transport system, beam instrumentation and control. * The first photo current from ERL SRF gun has been observed in fall 2014 after second attempt. Completion of the ERL returning loop components installation is scheduled for April 2015 following full power ERL commissioning. After ERL commissioning in BLDG912 the ERL will be relocated to RHIC IP2 to be used as low energy RHIC electron cooler.
* D.Kayran et al., First test results from SRF photoinjector for the R&D ERL at BNL, IPAC'14, pp. 748-750
TUIBLH1023
BNL, Upton, Long Island, New York, USA
Transfer Engineering and Manufacturing, Inc, Fremont, California, USA
Stangenes Industries, Palo Alto, California, USA
Stony Brook University, Stony Brook, USA
A prototype of the high average current polarized electron funneling gun as ERL-FFAG based eRHIC injector has built at BNL. In last year, we generated two beams from GaAs photocathodes by CW green laser and combined by a switched combiner field. We observed the combined beams on a YAG crystal ,measured the photocurrent and cathode lifetime by a Faraday cup. In this paper, we will describe the major components of the gun and beam line optics. We will also discuss the recent beam test results and high voltage conditioning results.
TUICLH1027
PKU, Beijing, People's Republic of China
BNL, Upton, Long Island, New York, USA
An alkali antimonide photocathode was tested in BNL 704 MHz SRF gun. The cathode QE and lifetime were measured inside the gun. We also observed a reduction on the QE upon cooling down to cryogenic temperature. In this paper, we propose an analytical model and present a Monte-Carlo simulation code to explain this QE decrease. Both results compared with experiments. Effect of cooling the cathode to cryogenic temperature and Schottky effect on QE will be discussed.