SLAC, Menlo Park, California, USA
FACET is a new facility under construction at the SLAC National Accelerator Laboratory. The FACET beam line is designed to provide 23 GeV tightly focused and compressed electron and positron bunches for beam driven plasma wakefield acceleration research and other experiments. Achieving optimal beam parameters for various experimental conditions requires the optics capability for tuning in a sufficiently wide range. This will be achieved by using optics tuning systems (knobs). Design of such systems for FACET is discussed.
SLAC, Menlo Park, California, USA
FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The FACET beamline consists of a chicane and final focus system to compress the 23 GeV, 3 nC electron bunches to ~20μm long and ~10μm wide. Simulations of the FACET beamline indicate the short-duration and large, 1.5% rms energy spread beams may suffer a factor of four emittance growth from a combination of chromaticity, incoherent synchrotron radiation (ISR), and coherent synchrotron radiation (CSR). Emittance growth is directly correlated to head erosion in plasma wakefield acceleration and is a limiting factor in single stage performance. Studies of the geometric, CSR, and ISR components are presented. Numerical calculation of the rms emittance can be overwhelmed by long tails in the simulated phase space distributions; more useful definitions of emittance are given. A complete simulation of the beamline is presented as well, which agrees with design specifications.
SLAC, Menlo Park, California, USA
The SUPER-B detector solenoid has a strong 1.5 T field in the Interaction Region (IR) area, and its tails extend over the range of several meters. The main effect of the solenoid field is the coupling of the horizontal and vertical betatron motion which needs to be corrected in order to preserve the small design beam size at the Interaction Point. The additional complications are that: a) due to the crossing angle the solenoid is not parallel to either of the two beams, thus leading to orbit and dispersion perturbations; b) the solenoid overlaps the innermost IR permanent quadrupoles, which will cause additional coupling effects. The proposed correction system provides local compensation of the solenoid effects independently for each side of the IR. It includes “bucking” solenoids to remove the unwanted long solenoid field tails and a set of skew quadrupoles, dipole correctors and anti-solenoids to cancel all linear perturbations to the optics. The details of the correction system design are presented.
SLAC, Menlo Park, California, USA
The SLAC Beam Physics group and collaborators continue to study options for implementing a near diffraction-limited ring-based light source in the 2.2-km PEP-II tunnel that will serve the SSRL scientific program in the future. The study team has completed the baseline design for a 4.5-GeV storage ring having 160-pm-rad emittance with stored beam current of 1.5 A, providing >1022 brightness for multi-keV photon beams from 3.5-m undulator sources. The team is now investigating possible 5-GeV ERL configurations which, similar to the Cornell and KEK ERL plans, would have ~30 pm-rad emittance with 100 mA current, and ~10 pm-rad emittance with 25 mA or less. In the next year, a diffraction-limited storage ring using on-axis injection in order to reach 30 pm-rad or less emittance will be investigated. An overview of the PEP-X design study and SSRL’s plans for defining the performance parameters that will guide the choice of implementation options is presented.
SLAC, Menlo Park, California, USA
INFN/LNF, Frascati (Roma), Italy
SLAC, Menlo Park, California, USA
SLAC is investigating long-range options for building a high performance light source machine while reusing the existing linac and PEP-II tunnels. One previously studied option is the PEP-X low emittance storage ring. The alternative option is based on a superconducting Energy Recovery Linac (ERL) and the PEP-X design. The ERL advantages are the low beam emittance, short bunch length and small energy spread leading to better qualities of the X-ray beams. Two ERL configurations differed by the location of the linac have been studied. Details of the lattice design and the results of beam transport simulations with the coherent synchrotron radiation effects are presented
SLAC, Menlo Park, California, USA
LPSC, Grenoble, France
CERN, Geneva, Switzerland
INFN/LNF, Frascati (Roma), Italy
BINP SB RAS, Novosibirsk, Russia
IN2P3-LAPP, Annecy-le-Vieux, France
CEA, Gif-sur-Yvette, France
INFN Genova, Genova, Italy
University of Pisa and INFN, Pisa, Italy
BINP, Novosibirsk, Russia
LAL, Orsay, France
The SuperB international team continues to optimize the design of an electron-positron collider, which will allow the enhanced study of the origins of flavor physics. The project combines the best features of a linear collider (high single-collision luminosity) and a storage-ring collider (high repetition rate), bringing together all accelerator physics aspects to make a very high luminosity of 1036 cm-2 s-1. This asymmetric-energy collider with a polarized electron beam will produce hundreds of millions of B-mesons at the Y(4S) resonance. The present design is based on extremely low emittance beams colliding at a large Piwinski angle to allow very low ßy* without the need for ultra short bunches. Use of crab-waist sextupoles will enhance the luminosity, suppressing dangerous resonances and allowing for a higher beam-beam parameter. The project has flexible beam parameters, improved dynamic aperture, and spin-rotators in the Low Energy Ring for longitudinal polarization of the electron beam at the Interaction Point. Optimized for best colliding-beam performance, the facility may also provide high-brightness photon beams for synchrotron-radiation applications.
