BNL, Upton, Long Island, New York, USA
Stony Brook University, Stony Brook, USA
RHIC operations with heavy ion beams at energies below 10 GeV/nucleon are motivated by a search for the QCD Critical Point. An electron cooler is proposed as a means to increase RHIC luminosity for collider operations at these low energies. The electron cooling system should be able to deliver an electron beam of adequate quality over a wide range of electron beam energies (0.9-5 MeV). It also should provide optimum 3-D cooling for both hadron beams in the collider. A method based on bunched electron beam, which is also a natural approach for high-energy electron cooling, is being developed. In this paper, we describe the requirements for this system, its design aspects, as well as the associated challenges.
BNL, Upton, Long Island, New York, USA
Niowave, Inc., Lansing, Michigan, USA
A 5-cell SRF cavity operating at 704 MHz will be used for Coherent Electron Cooling Proof of Principle (CeC PoP) system under development for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The CeC PoP experiment will demonstrate the ability of relativistic electrons to cool a single bunch of heavy ions in RHIC. The cavity will accelerate 2 MeV electrons from a 112 MHz SRF gun up 22 MeV. Novel mechanical designs, including the super fluid heat exchanger, helium vessel, vacuum vessel, tuner mechanism, and FPC are presented. Structural and modal analysis, using ANSYS were performed to confirm the cavity chamber and He vessel structural stability and to calculate the tuning sensitivity of the cavity. This paper provides an overview of the design, the project status and schedule of the 704 MHz 5-cell SRF for CeC PoP experiment.
BNL, Upton, Long Island, New York, USA
A Quarter-Wave Resonator (QWR) type SRF gun operating at 112 MHz will be used for Coherent Electron Cooling Proof of Principle (CeC PoP) system under development for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The CeC PoP experiment will demonstrate the ability of relativistic electrons to cool a single bunch of heavy ions in RHIC. This cavity is designed to generate a 2 MeV, high charge (several nC), low repetition rate (78 kHz) electron beam using a new fundamental power coupler (FPC) design approach. Structural and thermal analysis, using ANSYS were performed to confirm the FPC structural stability and to calculate the deflection due to heat load from RF power generation. This paper provides an overview of the design, structural and thermal analysis, test results, and FPC tuning drive system for the 112 MHz gun.
BNL, Upton, Long Island, New York, USA
Stony Brook University, Stony Brook, USA
SBU, Stony Brook, New York, USA
K2CsSb is a robust photocathode capable of generating electron beams with high peak, high average current and low thermal emittance. During the last two year, a great improvement in the design and fabrication of a reliable deposition system suitable for K2CsSb cathode growth and its insertion into BNL high current ERL SRF gun has been achieved. A standard procedure for the growth of multi-alkali cathodes combined with another procedure to transport these cathodes into the SRF gun was developed. The first cathode growth on a copper insertion was ready to mount into the 704MHz gun. In this article, we will describe the progress of cathode growth and transportation for ERL project. In particular, laser heating and the cathode growth on Ta will be included.
Stony Brook University, Stony Brook, USA
BNL, Upton, Long Island, New York, USA
SBU, Stony Brook, New York, USA
Diamond as a large energy gap material can be easily made into a negative electron affinity (NEA) device. Using a few keV primary electrons as input and a few kV bias, the NEA diamond will emit cold electrons into vacuum with a large gain. We had tested and reported the performance of the diamond amplifier in our DC system somewhere else. The best amplification achieved so far was above 170. Next step of the experiment is to test the diamond amplifier in the 112 MHz superconducting RF electron gun. In this report we describe the design and simulations of the diamond amplifier to be tested in our SRF gun, show the finished amplifier containing the DC primary gun and light optics. We also provide preliminary test results of the laser and electron beam transport.
Stony Brook University, Stony Brook, USA
BNL, Upton, Long Island, New York, USA
Niowave, Inc., Lansing, Michigan, USA
SBU, Stony Brook, New York, USA
The 112 MHz quarter wave superconducting electron gun was designed and built as an injector for the coherent electron cooling experiment. Besides that, the gun is suitable for testing various types of photocathodes thanks to its specially designed cathode holder. In recent RF tests of the gun at 4 K, the accelerating voltage reached 0.9 MV CW and more than 1 MV in pulsed mode. During this testing, we observed several multipacting barriers at low electromagnetic field levels. Since the final setup of the gun will be different from the cool down test configuration, we want to understand the exact location of the multipacting sites. We used Track3P to simulate multipacting. The results show several resonant trajectories that might be responsible for the observed barriers, but fortunately no strong multipacting barriers have been found in the cavity.
BNL, Upton, Long Island, New York, USA
Stony Brook University, Stony Brook, USA
Niowave, Inc., Lansing, Michigan, USA
Fermilab, Batavia, USA
SBU, Stony Brook, New York, USA
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
Efforts to experimentally prove a concept of the coherent electron cooling are underway at BNL. A short 22-MeV linac will provide high charge, low repetition rate beam to cool a single ion bunch in RHIC. The linac will consist of a 112 MHz SRF gun, two 500 MHz normal conducting bunching cavities and a 704 MHz five-cell accelerating SRF cavity. The paper describes the SRF and RF systems, the linac layout, and discusses the project status, first test results and schedule.
Stony Brook University, Stony Brook, USA
BNL, Upton, Long Island, New York, USA
SBU, Stony Brook, New York, USA
Diamond as a large energy gap material can be easily made into a negative electron affinity (NEA) device. Using a few keV primary electrons as input and a few kV bias, the NEA diamond will emit cold electrons into vacuum with a large gain. We had tested and reported the performance of the diamond amplifier in our DC system somewhere else. The best amplification achieved so far was above 170. Next step of the experiment is to test the diamond amplifier in the 112 MHz superconducting RF electron gun. In this report we describe the design and simulations of the diamond amplifier to be tested in our SRF gun, show the finished amplifier containing the DC primary gun and light optics. We also provide preliminary test results of the laser and electron beam transport.
Stony Brook University, Stony Brook, USA
BNL, Upton, Long Island, New York, USA
Niowave, Inc., Lansing, Michigan, USA
SBU, Stony Brook, New York, USA
The 112 MHz quarter wave superconducting electron gun was designed and built as an injector for the coherent electron cooling experiment. Besides that, the gun is suitable for testing various types of photocathodes thanks to its specially designed cathode holder. In recent RF tests of the gun at 4 K, the accelerating voltage reached 0.9 MV CW and more than 1 MV in pulsed mode. During this testing, we observed several multipacting barriers at low electromagnetic field levels. Since the final setup of the gun will be different from the cool down test configuration, we want to understand the exact location of the multipacting sites. We used Track3P to simulate multipacting. The results show several resonant trajectories that might be responsible for the observed barriers, but fortunately no strong multipacting barriers have been found in the cavity.
BNL, Upton, Long Island, New York, USA
Stony Brook University, Stony Brook, USA
Niowave, Inc., Lansing, Michigan, USA
Fermilab, Batavia, USA
SBU, Stony Brook, New York, USA
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
Efforts to experimentally prove a concept of the coherent electron cooling are underway at BNL. A short 22-MeV linac will provide high charge, low repetition rate beam to cool a single ion bunch in RHIC. The linac will consist of a 112 MHz SRF gun, two 500 MHz normal conducting bunching cavities and a 704 MHz five-cell accelerating SRF cavity. The paper describes the SRF and RF systems, the linac layout, and discusses the project status, first test results and schedule.