BNL, Upton, Long Island, New York
CEA, Gif-sur-Yvette
ESS-S, Lund
Fermilab, Batavia
CERN, Geneva
Funding: ESS-S Scandinavia Consortium
The conceptual design of the European Spallation Source-Scandinavia (ESS-S) is presented. The accelerator system baseline draws heavily on state-of-the-art mature technologies that are being employed in the CERN Linac4 and SPL projects, although advances with spoke resonator and sputtered superconducting cavities are also being evaluated for reliable performance. Irradiation damage due to proton beam losses is a key issue for linac and target components. Their optimized design is performed from an engineering perspective, using the last updated versions of mechanical design codes which were already qualified for irradiated components. Finally, future upgrades of power and intensity of the proton linac are considered, including the design optimization of the Target Station (proton/neutron convertor), with the possibility of increasing the average pulsed power deposition up to 7.5 MW. All possible upgrades will be taken into account for the final design review, in the frame of the costs and constraints given with the site decision.
BNL, Upton, Long Island, New York
CERN, Geneva
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In the article we review the nonlinear beam dynamics from nonlinear magnetic fields in the Relativistic Heavy Ion Collider. The nonlinear magnetic fields include the magnetic field errors in the interaction regions, chromatic sextupoles, and sextupole component from arc dipoles. Their effects on the beam dynamics and long-term dynamic apertures are evaluated. The online measurement and correction methods for the IR nonlinear errors, nonlinear chromaticity, and horizontal third order resonance are reviewed. The overall strategy for the nonlinear effect correction in the RHIC is discussed.
CERN, Geneva
INFN-Roma, Roma
BNL, Upton, Long Island, New York
The UA9 experiment will take place in 2009 at the CERN-SPS and will evaluate the feasibility of silicon crystals as primary collimators for a storage ring. A crystal placed at 6 σ from the beam core will deviate protons towards two roman pots and a tungsten absorber (TAL). In this paper the authors show simulations of the expected beam dynamics and of the capture efficiency into the secondary collimator. The result of these simulations will guide us in interpreting the experimental data expected in UA9.
CERN, Geneva
BNL, Upton, Long Island, New York
EPFL, Lausanne
The grazing function g is introduced – a synchrobetatron optical quantity that parametrizes the rate of change of total angle with respect to synchrotron amplitude for particles grazing a collimator or aperture. The grazing function is particularly important for crystal collimators, which have limited acceptance angles. The implications for RHIC, SPS, Tevatron and LHC crystal implementations are discussed. An analytic approximation is derived for the maximum value of g in a matched FODO cell, and is shown to be in good agreement with a realistic numerical example. The grazing function scales linearly with FODO cell bend angle, but to is independent of FODO cell length.
Fermilab, Batavia
CERN, Geneva
IHEP Protvino, Protvino, Moscow Region
INFN-Ferrara, Ferrara
PNPI, Gatchina, Leningrad District
BNL, Upton, Long Island, New York
Università dell'Insubria & INFN Milano Bicocca, Como
Enrico Fermi Institute, University of Chicago, Chicago, Illinois
Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
Bent-crystal channeling is a technique with a potential to increase the beam-halo collimation efficiency at high-energy colliders. First measurements at the Tevatron in 2005 have shown that using a 5-mm silicon crystal to deflect the proton beam halo onto a secondary collimator improves the system performance by reducing the machine impedance, beam losses in the collider detectors and irradiation of the superconducting magnets, all in agreement with simulations. Recent results, obtained with substantially improved goniometer and enhanced beam diagnostics, are reported showing channeling collimation of the ~1-TeV circulating proton beam halo at the Tevatron collider. Comprehensive results of computer modeling are presented which allow further developments of the T-980 experiment towards a robust system compatible with requirements to high-efficient collimation at the Tevatron and LHC hadron colliders.
CERN, Geneva
BNL, Upton, Long Island, New York
The effect of magnet misalignments in the beam orbit and linear optics functions are reviewed and correction schemes are applied to the negative momentum compaction lattices of PS2. Chromaticity correction schemes are also proposed and tested with respect to off-momentum optics properties. The impact of the correction schemes in the dynamic aperture of the different lattices is finally evaluated.
CERN, Geneva
BNL, Upton, Long Island, New York
In view of the CERN Proton Synchrotron proposed replacement with a new ring (PS2), a detailed optics design as been undertaken following the evaluation of several lattice options. The basic arc module consists of cells providing negative momentum compaction. The straight section is formed with a combination of FODO and quadrupole triplet cells, to accommodate the injection and extraction systems, in particular the H- injection elements. The arc is matched to the straight section with a dispersion suppressor and matching module. Different lattices are compared with respect to their linear optics functions, tuning flexibility and geometrical acceptance properties.