ORNL, Oak Ridge, Tennessee
The Spallation Neutron Source has been operational for over three years, characterized by a rapid power ramp-up over the first two years and operation at a beam power of about one MW for the past year. Equipment reliability is a major concern at a user facility like SNS, and beam power has been limited primarily by equipment robustness to date. Beam loss is also a major concern, and is the primary driver in beam tuning. Many beam loss reductions are found empirically, and are not well understood. SNS is operating at the MW level with uncontrolled beam loss below the 1 W/m level, as required for hands on maintenance, and has not limited the operational beam power to date.
KEK, Ibaraki
The J-PARC facility consists of linac, 3 GeV RCS (Rapid Cycling Synchrotron), 50 GeV MR (Main Ring synchrotron, 30 GeV at the present) and three experimental facilities, the MLF (Material and Life science experimental Facility), the hadron experimental facility and the neutrino beam line. The RCS has started 120 kW beam delivery to the MLF (Material and Life science experimental Facility) since November 2009. The MR delivers 50 kW beam to the neutrino beam line by fast extraction and a few kW beam to the hadron facility by slow extraction. In this paper, status of the high intensity operation of the J-PARC accelerators is presented. Beam dynamics studies and our practical experience at the high power beam are discussed. In addition, future plans and strategies to increase the beam intensity are also presented briefly.
CERN, Geneva
The unprecedented design intensities of the LHC require several important advances in beam collimation. With its more than 100 collimators, acting on various planes and beams, the LHC collimation system is the biggest and most performing such system ever designed and constructed. The solution for LHC collimation is explained, the technical components are introduced and the initial performance is presented. Residual beam leakage from the system is analyzed and compared to simulations. It is shown that the observed leakage is in agreement with prior predictions. Measurements are presented which show that collimation efficiencies of better than 99.98 % have been measured with the 3.5 TeV proton beams of the LHC.