THA2WD —  WG-D   (21-Jun-18   11:00—12:30)
Chair: Y. Papaphilippou, CERN, Geneva, Switzerland
Paper Title Page
THA2WD01 Operation Challenges and Performance of the LHC During Run II -1
  • R. Steerenberg, J. Wenninger
    CERN, Geneva, Switzerland
  The CERN Large Hadron Collider Run II saw an important increase in beam performance through both, improvements in the LHC and an increased beam brightness from the injectors, leading to a peak luminosity that exceeds the LHC design luminosity by more than a factor two. This contribution will give an overview of run 2, the main challenges encountered and it will address the measures applied to deal with and make use of the increased beam brightness. Finally potential areas where further performance improvement can be a realized will be identified.  
slides icon Slides THA2WD01 [6.709 MB]  
Low Energy RHIC electron Cooling (LEReC): Challenges and Commissioning Progress  
  • A.V. Fedotov
    BNL, Upton, Long Island, New York, USA
  Funding: Work supported by the U.S. Department of Energy.
The low-energy physics program at the Relativistic Heavy Ion Collider (RHIC), motivated by a search for the QCD phase transition critical point, requires operation at very low energies. At these energies, large nonlinear magnetic field errors and large beam sizes produce low beam lifetimes. A variety of beam dynamics effects such as IBS, space charge and beam-beam forces also contribute. An electron cooling technique is effective in counteracting luminosity degradation due to the IBS. To improve luminosities for the low energies of operation, the low energy RHIC electron cooler (LEReC) was constructed and is presently under commissioning. Required electron beam and its acceleration is provided by the photoemission electron gun followed by an RF accelerator. As a first step, one has to commission high-brightness high-current electron accelerator and achieve beam parameters suitable for cooling. This will be followed by commissioning of bunched electron beam cooling, and finally by producing high-brightness hadron beams via the cooling process. Here, we describe design aspects and challenges of such an approach, as well as summarize first commissioning results.
on behalf of the LEReC team.
slides icon Slides THA2WD02 [4.416 MB]  
THA2WD03 Real-Time Measurement of Fluctuations of Building Floor and Installed Devices of Large Scientific Equipment -1
  • H. J. Choi, J.H. Han, H.-S. Kang, S.H. Kim, H.-G. Lee, S.B. Lee
    PAL, Pohang, Kyungbuk, Republic of Korea
  Several parts that comprise the large scientific equipment should be installed and operated at precise three-dimensional location coordinates X, Y, and Z through survey and alignment to ensure their optimal performance. As time goes by, however, the ground goes through uplift and subsidence, which consequently changes the coordinates of installed components and leads to alignment errors ΔX, ΔY, and ΔZ. As a result, the system parameters change, and the performance of the large scientific equipment deteriorates accordingly. Measuring the change in locations of systems comprising the large scientific equipment in real time would make it possible to predict alignment errors, locate any region with greater changes, realign components in the region fast, and shorten the time of survey and realignment. For this purpose, a WPS's (wire position sensor) are installed in undulator section and a HLS's (hydrostatic leveling sensor) are installed in PAL-XFEL building. This paper is designed to introduce installation status of HLS and WPS, operation status.  
slides icon Slides THA2WD03 [21.186 MB]