BNL, Upton, Long Island, New York, USA
Tech-X, Boulder, Colorado, USA
Niowave, Inc., Lansing, Michigan, USA
SUNY SB, Stony Brook, New York, USA
BINP SB RAS, Novosibirsk, Russia
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
The Coherent Electron Cooling Proof of Principle (CeC PoP) system is being installed in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It will demonstrate the ability of relativistic electrons to cool a single bunch of heavy ions in RHIC. This technique may increase the beam luminosity by as much as tenfold. Within the scope of this experiment, a 112 MHz 2 MeV Superconducting Radio Frequency (SRF) electron gun coupled with a cathode stalk mechanism, two normal conducting 500 MHz single-cell bunching cavities, a 704 MHz 20 MeV 5-cell SRF cavity and a helical undulator will be used. In this paper, we provide an overview of the engineering design for this project, test results and discuss project status and plansd.
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). This facility enables testing of concepts relevant for high-energy coherent electron cooling, electron-ion colliders, and high repetition rate Free-Electron Lasers. The ERL will be capable of providing electron beams with sufficient quality to produce high repetition rate THz and X-ray radiation. When completed the SRF photoinjector will provide 2 MeV energy and 300 mA average beam current. The injector for the R&D ERL was installed in 2012, this includes a 704MHz SRF gun* with multi-alkali photocathode, cryo-system upgrade and a novel emittance preservation zigzag-like low energy merger system. We describe the design and major components of the R&D ERL injector then report the first experimental results and experiences learned in the first stage of beam commissioning of the BNL R&D ERL.
* Wencan Xu et al., “Commissioning SRF gun for the R&D ERL at BNL”, IPAC2013 proceedings, WEPWO085.
BNL, Upton, Long Island, New York, USA
The head-on beam-beam interaction is the dominant luminosity limiting effect in polarized proton operation in RHIC. To mitigate this effect two electron lenses were installed in the two RHIC rings. We summarize the hardware and electron beam commissioning results to date, and report on the first experience with the electron-hadron beam interaction. In 2014 RHIC is operating with gold beams only. In this case the luminosity is not limited by head-on beam-beam interactions and compensation is not necessary. The goals of this year’s commissioning efforts are a test of all instrumentation; the demonstration of electron and gold beam overlap; the demonstration of electron beam parameters that are sufficiently stable to have no negative impact on the gold beam lifetime; and the measurement of the tune footprint compression from the beam overlap. With these demonstrations, and a lattice with a phase advance that has a multiple of 180 degrees between the beam-beam interaction and electron lens locations, head-on beam-beam compensation can be commissioned in the following year with proton beams.
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 the 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 new technique of cooling proton and ion beams that may increase the beam luminosity in certain cases, by as much as tenfold. The 704 MHz cavity will accelerate 2 MeV electrons from a 112 MHz SRF gun up 22 MeV. Novel mechanical designs, including a super fluid heat exchanger, helium vessel, vacuum vessel and tuner mechanism are presented. Structural and thermal analysis, using ANSYS were performed to confirm the mechanical tuning system structural stability. 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
PVI, Oxnard, California, USA
An in-situ technique for coating stainless steel vacuum tubes with Cu was developed to mitigate the problems of wall resistivity that leads to unacceptable ohmic heating of superconducting magnets cold bore and electron cloud generation in RHIC that can limit future machine luminosity enhancement. Room temperature RF resistivity of 10 μm Cu coated stainless steel RHIC beam tube has conductivity close to copper tubing. Before coating the RHIC beam pipe with copper, it is imperative to test the Cu coating’s conductivity at cryogenic. A folded quarter wave resonator structure has been designed and built for insertion in a cryogenic system to measure RF resistivity of copper coated RHIC tubing at liquid helium temperatures. The design is based on making the resonator structure out of a superconducting material such that the copper coating is the most lossy material. RHIC tubing samples prepared with different magnetron sputtering deposition modes are to be optimized by iterative processes. Additionally, this device can also be used for the development of better, cheaper SRF cavities and electron guns. The apparatus and its design details will be presented.