Author: McIntyre, G.T.
Paper Title Page
TUP054 Mechanical Design of 56 MHz Superconducting RF Cavity for RHIC Collider 907
 
  • C. Pai, I. Ben-Zvi, A. Burrill, X. Chang, G.T. McIntyre, R. Than, J.E. Tuozzolo, Q. Wu
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A 56 MHz Superconducting RF Cavity operating at 4.4K is being constructed for the RHIC collider. This cavity is a quarter wave resonator with beam transmission along the centreline. This cavity will increase collision luminosity by providing a large longitudinal bucket for stored bunches of RHIC ion beam. The major components of this assembly are the niobium cavity with the mechanical tuner, its titanium helium vessel and vacuum cryostat, the support system, and the ports for HOM and fundamental dampers. The cavity and its helium vessel must meet the ASME pressure vessel code and it must not be sensitive to frequency shift due to pressure fluctuations from the helium supply system. Frequency tuning achieved by a two stage mechanical tuner is required to meet performance parameters. This tuner mechanism pushes and pulls the tuning plate in the gap of niobium cavity. The tuner mechanism has two separate drive systems to provide both coarse and fine tuning capabilities. This paper discusses the design detail and how the design requirements are met.
 
 
TUP059 Multipacting in a Grooved Choke Joint at SRF Gun for BNL ERL Prototype 922
 
  • W. Xu, S.A. Belomestnykh, I. Ben-Zvi, A. Burrill, D. Kayran, G.T. McIntyre, B. Sheehy
    BNL, Upton, Long Island, New York, USA
  • D. Holmes
    AES, Medford, NY, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The 703 MHz superconducting gun for BNL ERL prototype was tested at JLab with and without choke-joint and cathode stalk. Without choke-joint and cathode stalk, the gradient reached 25MV/m with Q0~6·109. The gun cathode insertion port is equipped with a choke joint with triangular grooves for multipacting suppression. We carried out tests with choke-joint and cathode stalk. The test results show that there are at least two barriers at about 5MV/m and 3.5 MV/m. We considered several possibilities and finally found that the limitation was because the triangular grooves were rounded after BCP, which caused strong multipacting in the choke-joint. This paper presents the primary test result of test results of the gun and discusses the multipacting analysis in the choke-joint. It also suggests possible solutions for the gun and multipacting suppressing for a similar structure.
 
 
TUP163 Design Construction and Test Results of a HTS Solenoid for Energy Recovery Linac 1127
 
  • R.C. Gupta, M. Anerella, I. Ben-Zvi, G. Ganetis, D. Kayran, G.T. McIntyre, J.F. Muratore, S.R. Plate, W. Sampson
    BNL, Upton, Long Island, New York, USA
  • M.D. Cole, D. Holmes
    AES, Medford, NY, USA
 
  Funding: This work is supported by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886.
An innovative feature of the proposed Energy Recovery Linac (ERL) at Brookhaven National Laboratory (BNL) is the use of a solenoid made with High Temperature Superconductor (HTS) with the Superconducting RF cavity. The use of HTS in the solenoid offers many advantages. The solenoid is located in the transition region (4 K to room temperature) where the temperature is too high for a conventional low temperature superconductor and the heat load on the cryogenic system too high for copper coils. Proximity to the cavity provides early focusing and thus a reduction in the emittance of the electron beam. In addition, taking full advantage of the high critical temperature of HTS, the solenoid has been designed to reach the required field at ~77 K, which can be obtained with liquid nitrogen. This significantly reduces the cost of testing and allows a variety of critical pre‐tests (e.g. measurements of the axial and fringe fields) which would have been very expensive at 4 K in liquid helium because of the additional requirements for a cryostat and associated facilities. This paper will present the design, construction, test results and current status of this HTS solenoid.
 
 
TUP224 Cryogenic Vertical Test Facility for the SRF Cavities at BNL 1238
 
  • R. Than, I. Ben-Zvi, A. Burrill, M.C. Grau, D.L. Lederle, C.J. Liaw, G.T. McIntyre, D. Pate, R. Porqueddu, T.N. Tallerico, J.E. Tuozzolo
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
A vertical facility has been constructed to test SRF cavities and can be utilized for other use. The liquid helium volume for the large vertical dewar is approximate 84 inches tall by 40 inches diameter with a working clear inner diameter of 38 inch with the inner cold magnetic shield system installed. For radiation enclosure, the test dewar is situated inside a concrete block structure. The structure is above ground and is accessible from the top, and has a retractable concrete roof. A second radiation concrete facility, with ground level access via a labyrinth is also available for testing of smaller cavities in 2 smaller dewars.
 
 
TUP225 Overview of Recent Studies and Modifications Being Made to RHIC to Mitigate the Effects of a Potential Failure to the Helium Distribution System 1241
 
  • J.E. Tuozzolo, D. Bruno, A. Di Lieto, G. Heppner, R. Karol, E.T. Lessard, C.J. Liaw, G.T. McIntyre, C. Mi, J. Reich, J. Sandberg, S.K. Seberg, L. Smart, T.N. Tallerico, R. Than, C. Theisen, R.J. Todd, R. Zapasek
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In order to cool the superconducting magnets in RHIC, its helium refrigerator distributes 4.5 K helium throughout the tunnel via a series of distribution and return lines. The worst case for failure would be a release from the magnet distribution line, which operates at 3.5 to 4.5 atmospheres and contains the energized magnet bus. Should the bus insulation system fail or an electrical connection open, there is the potential for releasing up to 70 MJoules of stored energy. Studies were done to determine release rate of the helium and the resultant reduction in O2 concentration in the RHIC tunnel and service buildings. Equipment and components were also reviewed for reliability and the effects of 10 years of operations. Modifications were made to reduce the likelihood of failure and to reduce the amount of helium gas that could be released into tunnels and service buildings while personnel are present. This paper describes the issues reviewed, the steps taken, and remaining work to be done to reduce the hazards.
 
 
TUP272 Analysis and Comparison to Test of AlMg3 Seals Near a SRF Cavity 1331
 
  • T. Schultheiss, C.M. Astefanous, M.D. Cole, D. Holmes, J. Rathke
    AES, Medford, NY, USA
  • I. Ben-Zvi, D. Kayran, G.T. McIntyre, B. Sheehy, R. Than
    BNL, Upton, Long Island, New York, USA
  • A. Burrill
    JLAB, Newport News, Virginia, USA
 
  The Energy Recovery Linac (ERL) presently under construction at Brookhaven National Laboratory is being developed as research and development towards eRHIC, an Electron-Heavy Ion Collider. The experimental 5-cell 703.75 MHz (ECX) cavity was recently evaluated at continuous field levels greater than 10 MV/m. These tests indicated stored energy limits of the cavity on the order of 75 joules. During design of the cavity the cold flange on one side was moved closer to the cavity to allow the cavity to fit into the available chemical processing chamber at Jefferson Laboratory. RF and thermal analysis of the AlMg3 seal region of the closer side indicate this to be the prime candidate limiting the fields. This work presents the analysis results and compares these results to test data.  
 
TUOAN2 High Luminosity Electron-Hadron Collider eRHIC 693
 
  • V. Ptitsyn, E.C. Aschenauer, M. Bai, J. Beebe-Wang, S.A. Belomestnykh, I. Ben-Zvi, M. Blaskiewicz, R. Calaga, X. Chang, A.V. Fedotov, H. Hahn, L.R. Hammons, Y. Hao, P. He, W.A. Jackson, A.K. Jain, E.C. Johnson, D. Kayran, J. Kewisch, V. Litvinenko, G.J. Mahler, G.T. McIntyre, W. Meng, M.G. Minty, B. Parker, A.I. Pikin, T. Rao, T. Roser, B. Sheehy, J. Skaritka, S. Tepikian, R. Than, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, G. Wang, Q. Wu, W. Xu, A. Zelenski
    BNL, Upton, Long Island, New York, USA
  • E. Pozdeyev
    FRIB, East Lansing, Michigan, USA
  • E. Tsentalovich
    MIT, Middleton, Massachusetts, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
We present the design of future high-energy high-luminosity electron-hadron collider at RHIC called eRHIC. We plan on adding 20 (potentially 30) GeV energy recovery linacs to accelerate and to collide polarized and unpolarized electrons with hadrons in RHIC. The center-of-mass energy of eRHIC will range from 30 to 200 GeV. The luminosity exceeding 1034 cm-2 s-1 can be achieved in eRHIC using the low-beta interaction region with a 10 mrad crab crossing. We report on the progress of important eRHIC R&D such as the high-current polarized electron source, the coherent electron cooling and the compact magnets for recirculating passes. A natural staging scenario of step-by-step increases of the electron beam energy by builiding-up of eRHIC's SRF linacs and a potential of adding polarized positrons are also presented.
 
slides icon Slides TUOAN2 [4.244 MB]  
 
TUP056 BNL 703 MHz Superconducting RF Cavity Testing 913
 
  • B. Sheehy, Z. Altinbas, I. Ben-Zvi, D.M. Gassner, H. Hahn, L.R. Hammons, J.P. Jamilkowski, D. Kayran, J. Kewisch, N. Laloudakis, D.L. Lederle, V. Litvinenko, G.T. McIntyre, D. Pate, D. Phillips, C. Schultheiss, T. Seda, R. Than, W. Xu, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • A. Burrill
    JLAB, Newport News, Virginia, USA
  • T. Schultheiss
    AES, Medford, NY, USA
 
  Funding: This work received support from Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The Brookhaven National Laboratory (BNL) 5-cell, 703 MHz superconducting RF accelerating cavity has been installed in the high-current energy recovery linac (ERL) experiment. This experiment will function as a proving ground for the development of high-current machines in general and is particularly targeted at beam development for an electron-ion collider (eRHIC). The cavity performed well in vertical tests, demonstrating gradients of 20 MV/m and a Q0 of 1010. Here we will present its performance in the horizontal tests, and discuss technical issues involved in its implementation in the ERL.
 
 
TUP061 FPC Conditioning Cart at BNL 928
 
  • W. Xu, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, A. Burrill, S. Deonarine, D.M. Gassner, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, L. Masi, G.T. McIntyre, D. Pate, D. Phillips, T. Seda, A.N. Steszyn, T.N. Tallerico, R.J. Todd, D. Weiss, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • M.D. Cole, G.J. Whitbeck
    AES, Medford, NY, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The 703MHz superconducting gun will have 2 fundamental power couplers (FPCs). Each FPC will deliver up to 500kW of RF power. In order to prepare the couplers for high power RF service and process multipacting, the FPCs should be conditioned before they are installed in the gun. A conditioning cart based test stand, which includes a vacuum pumping system, controllable bake-out system, diagnostics, interlocks and data log system has been designed, constructed and commissioned by collaboration of BNL and AES. This paper presents FPC conditioning cart systems and summarizes the conditioning process and results.
 
 
THP006 Status of High Current R&D Energy Recovery Linac at Brookhaven National Laboratory 2148
 
  • D. Kayran, Z. Altinbas, D.R. Beavis, I. Ben-Zvi, R. Calaga, D.M. Gassner, H. Hahn, L.R. Hammons, A.K. Jain, J.P. Jamilkowski, N. Laloudakis, R.F. Lambiase, D.L. Lederle, V. Litvinenko, G.J. Mahler, G.T. McIntyre, W. Meng, B. Oerter, D. Pate, D. Phillips, J. Reich, T. Roser, C. Schultheiss, B. Sheehy, T. Srinivasan-Rao, R. Than, J.E. Tuozzolo, D. Weiss, W. Xu, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
 
  An ampere-class 20 MeV superconducting energy recovery linac (ERL) is under construction at Brookhaven National Laboratory (BNL) for testing of concepts relevant for high-energy coherent electron cooling and electron-ion colliders. One of the goals is to demonstrate an electron beam with high charge per bunch (~5 nC) and low normalized emittance (~5 mm-mrad) at an energy of 20 MeV. A flexible lattice for the ERL loop provides a test bed for investigating issues of transverse and longitudinal instabilities and diagnostics for CW beam. A superconducting 703 MHz RF photo-injector is considered as an electron source for such a facility. We will start with a straight pass (gun/cavity/beam stop) test for gun performance studies. Later, we will install and test a novel injection line concept for emittance preservation in a lower-energy merger. Here we present the status and our plans for construction and commissioning of this facility.