THOBS —  Accelerator Technology V   (31-Mar-11   10:00—12:00)
Chair: P. Schmor, TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
Paper Title Page
THOBS1 Developments in Superconducting Insertion Devices 2077
 
  • E.R. Moog, Y. Ivanyushenkov
    ANL, Argonne, USA
 
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A number of superconducting wigglers are installed and in operation worldwide. Superconducting undulators, with their shorter periods and more demanding field quality requirements, present additional challenges and are still under development. Superconducting technology can produce a higher magnetic field strength on the beam axis than can a permanent-magnet-based undulator. This makes shorter period undulators feasible – they will still reach high enough field to have a reasonable photon energy tuning range. The shorter period device gives higher photon brightness at higher photon energies, opening up new opportunities for photon-hungry applications that require higher photon energies. Many light sources are interested in having a superconducting undulator; a few, including the Advanced Photon Source, have ongoing projects and are making significant progress. The status of these projects will be discussed.
 
slides icon Slides THOBS1 [3.427 MB]  
 
THOBS2 Optimization of Magnet Stability and Alignment for NSLS-II 2082
 
  • S.K. Sharma, L. Doom, A.K. Jain, P.N. Joshi, F. Lincoln, V. Ravindranath
    BNL, Upton, Long Island, New York, USA
 
  Funding: This work was supported by Department of Energy contract DE-AC02-98CH10886
The high-brightness design of NSLS-II requires uncorrelated vertical RMS motion of the multipole magnets on a girder to be less than 25 nm. Also, the highly nonlinear lattice requires alignment of the multipole magnets to 30 microns. The speaker will describe the stability of the girder-magnets assembly and the factors affecting it, such as ambient ground motion and temperature fluctuations in the storage ring. Technical solutions to achieve the desired stability will be presented as well.
 
slides icon Slides THOBS2 [4.431 MB]  
 
THOBS3 Magnetic Alignment of Pulsed Solenoids using the Pulsed Wire Method 2087
 
  • D. Arbelaez, J.W. Kwan, T.M. Lipton, A. Madur, W.L. Waldron
    LBNL, Berkeley, California, USA
 
  Funding: This work was supported by the Director, Office of Science, Office of Fusion Energy Sciences, of the U.S. Department of Energy prepared by LBNL under Contract No. DE-AC02-05CH11231.
A unique application of the pulsed-wire measurement method has been implemented for alignment of 2.5T pulsed solenoid magnets. The magnetic axis measurement has been shown to have a resolution of better than 25 μm. The accuracy of the technique allows for the identification of inherent field errors due to, for example, the winding layer transitions and the current leads. The alignment system is developed for the induction accelerator NDCX-II under construction at LBNL, an upgraded Neutralized Drift Compression eXperiment for research on warm dense matter and heavy ion fusion. Precise alignment is essential for NDCX-II, since the ion beam has a large energy spread associated with the rapid pulse compression such that misalignments lead to corkscrew deformation of the beam and reduced intensity at focus. The ability to align the magnetic axis of the pulsed solenoids to within 100 μm of the induction cell axis has been demonstrated.
 
slides icon Slides THOBS3 [3.246 MB]  
 
THOBS4 Current Status of Insertion Device Development at the NSLS-II and its Future Plans 2090
 
  • T. Tanabe, O.V. Chubar, T.M. Corwin, D.A. Harder, P. He, C.A. Kitegi, G. Rakowsky, J. Rank, C. Rhein, C.J. Spataro
    BNL, Upton, Long Island, New York, USA
 
  Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH1-886 with the U.S. Department of Energy.
National Synchrotron Light Source-II (NSLS-II) project is currently under construction. Procurement of various insertion devices (IDs) has begun. IDs in the project baseline scope include six 3.5m long damping wigglers (DWs) with 100mm period, two 2.0m Elliptically Polarizing Undulator (EPU) with 49mm period, two 3.0m-20mm period IVUs and one 1.5m-21mm IVU. Recently a special device for inelastic X-ray scattering beamline has been added to the collection of baseline devices. This is a special wide pole IVU with 22mm period for a long straight section. Three pole wigglers with 28mm gap and peak field over 1T will be utilized for NSLS bending magnet users. Examples of R&D work for future devices are: 1) Development of in-vacuum magnetic measurement system (IVMMS), 2) Use of new type of magnet such as PrFeB for improved performance on cryo-permanent magnet undulator (CPMU), 3) Development of closed loop He gas refrigerator with a linear motor actuator, 4) Adaptive gap undulator (AGU) 5) Various field measurement technique improvement. Design features of the baseline devices, ID-Magnetic Measurement Facility and the future plans for NSLS-II ID activities are described.
 
slides icon Slides THOBS4 [4.171 MB]  
 
THOBS5 Extruded Aluminum Vacuum Chambers for Insertion Devices 2093
 
  • E. Trakhtenberg, P.K. Den Hartog, G.E. Wiemerslage
    ANL, Argonne, USA
 
  Funding: Work is supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Science under Contract No. DE-AC02-06CH 11357.
Extruded aluminum vacuum chambers are commonly used in the storage rings of synchrotron facilities. For 18 years the APS has designed and fabricated vacuum chambers made from extruded aluminum for use with insertion devices at the APS and for use at other facilities including BESSY II, the Swiss Light Source (SLS), the Canadian Light Source (CLS), the TESLA Test Facility (TTF), and the European Synchrotron Radiation Facility (ESRF). Most recently extruded aluminum chambers were developed for LCLS with a 0.5-mm wall thickness along the entire 3.8-meter length. Surface roughness for the LCLS vacuum chamber interior was reduced, on average, to less than 300 nm through an abrasive flow polishing technique. Currently under development is an extruded aluminum chamber for the superconducting undulator at the APS. So far, 120 vacuum chambers have been produced with these methods. Results of the development, construction, and manufacturing of extruded aluminum vacuum chambers with small vertical apertures and thin walls are presented. The design, technological challenges, and positive and negative experiences are discussed.
 
slides icon Slides THOBS5 [7.855 MB]  
 
THOBS6 Thin Film Coatings for Suppressing Electron Multipacting in Particle Accelerators 2096
 
  • P. Costa Pinto, S. Calatroni, P. Chiggiato, H. Neupert, E.N. Shaposhnikova, M. Taborelli, W. Vollenberg, C. Yin Vallgren
    CERN, Geneva, Switzerland
 
  Thin film coatings are an effective way for suppressing electron multipacting in particle accelerators. For bakeable beam pipes, the TiZrV Non Evaporable Getter (NEG) developed at CERN can provide a Secondary Electron Yield (SEY) of 1.1 after activation at 180oC (24h). The coating process was implemented in large scale to coat the long straight sections and the experimental beam pipes for the Large Hadron Collider (LHC). For non bakeable beam pipes, as those of the Super Proton Synchrotron (SPS), CERN started a campaign to develop a coating having a low SEY without need of in situ heating. Magnetron sputtered carbon thin films have shown SEY of 1 with marginal deterioration when exposed in air for months. This material is now being tested in both laboratory and accelerator environment. At CERN’s SPS, tests with electron cloud monitors attached to carbon coated chambers show no degradation of the coating after two years of operation interleaved with a total of 3 months of air exposure during shutdown periods. This paper presents the SEY characteristics of both TiZrV and carbon films, the coating processes and the proposed route towards large scale production for the carbon coatings.  
slides icon Slides THOBS6 [4.620 MB]