CERN, Geneva
LAL, Orsay
INFN/LNF, Frascati (Roma)
Installation of the new photo-injector for the CTF3 drive beam (PHIN) has been completed on a stand-alone test bench. The photo-injector operates with a 2.5 cell RF gun at 3 GHz, using a Cs2Te photocathode illuminated by a UV laser beam. The test bench is equipped with different beam monitoring devices as well as a 90-degree spectrometer. A grid of 200 micrometer wide slits can be inserted for emittance measurements. The laser used to trigger the photo-emission process is a Nd:YLF system consisting of an oscillator and a preamplifier operating at 1.5 GHz and two powerful amplifier stages. The infrared radiation produced is frequency quadrupled in two stages to obtain the UV. A Pockels cell allows adjusting the length of the pulse train between 50 nanoseconds and 50 microseconds. The nominal train length for CTF3 is 1.272 microseconds (1908 bunches). The first electron beam in PHIN was produced in November 2008. In this paper, results concerning the operation of the laser system and measurements performed to characterize the electron beam are presented.
CERN, Geneva
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
IHEP Beijing, Beijing
LAL, Orsay
KEK, Ibaraki
UMAN, Manchester
SLAC, Menlo Park, California
The CLIC Final Focus System has considerably larger chromaticity than those of ILC and its scaled test machine ATF2. We propose to reduce the IP betas of ATF2 to reach a CLIC-like chromaticity. This would also allow to study the FFS tuning difficulty as function of the IP beam spot size. Both the ILC and CLIC projects will largely benefit from the ATF2 experience at these ultra-low IP betas.
SLAC, Menlo Park, California
CERN, Geneva
Funding: Work supported by the DOE under contract DE-AC02-76SF00515.
Plasma Wake-Field Acceleration (PWFA) has demonstrated acceleration gradients above 50 GeV/m. Simulations have shown drive/witness bunch configurations that yield small energy spreads in the accelerated witness bunch and high energy transfer efficiency from the drive bunch to the witness bunch, ranging from 30% for a Gaussian drive bunch to 95% for bunch with triangular shaped longitudinal profile. These results open the opportunity for a linear collider that could be compact, efficient and more cost effective than the present microwave technologies. A concept of a PWFA-based Linear Collider (PWFA-LC) has been developed by the PWFA collaboration. Here we will describe the conceptual design and optimization of the drive beam, which includes the drive beam linac and distribution system. We apply experience of the CLIC drive beam design and demonstration in the CLIC Test Facility (CTF3) to this study. We discuss parameter optimization of the drive beam linac structure and evaluate the drive linac efficiency in terms of the drive beam distribution scheme and the klystron / modulator requirements.
CERN, Geneva
NSC/KIPT, Kharkov
IN2P3 IPNL, Villeurbanne
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
LAL, Orsay
ANL, Argonne
KEK, Ibaraki
HU/AdSM, Higashi-Hiroshima
BNL, Upton, Long Island, New York
Hiroshima University, Graduate School of Science, Higashi-Hiroshima
The CLIC polarized positron source is based on a positron production scheme in which polarized photons are produced by Compton process. Compton backscattering happens in a so-called "Compton ring" where an electron beam of 1.06 GeV interacts with a powerful laser beam amplified in an optical resonator. The circularly-polarized gamma rays are sent on to a target, producing pairs of longitudinally polarized electrons and positrons. An Adiabatic Matching Device maximizes the capture of the positrons. A normal-conducting 2 GHz Linac accelerates the beam up to 2.424 GeV before injection into the Pre-Damping Ring (PDR). The nominal CLIC bunch population is 4.4x109 particles per bunch. Since the photon flux coming out from a "Compton ring" is not sufficient to obtain the requested charge, a stacking process is required in the PDR. Another option is to use a "Compton Energy Recovery Linac" where a quasi-continual stacking in the PDR could be achieved. A third option is to use a "Compton Linac" which would not require stacking. We describe the overall scheme as well as advantages and constraints of the three different options.
CERN, Geneva
N.U, Nigde
Cockcroft Institute, Warrington, Cheshire
Ankara University, Faculty of Sciences, Tandogan/Ankara
The University of Liverpool, Liverpool
KEK, Ibaraki
TOBB ETU, Ankara
BNL, Upton, Long Island, New York
Sub-atomic physics at the energy frontier probes the structure of the fundamental quanta of the Universe. The Large Hadron Collider (LHC) at CERN opens for the first time the “terascale” (TeV energy scale) to experimental scrutiny, exposing the physics of the Universe at the sub-attometric (~10-19 m, 10-10 as) scale. The LHC will also take the science of nuclear matter to hitherto unparalleled energy densities (low-x physics). The hadron beams, protons or ions, in the LHC underpin this horizon, and also offer new experimental possibilities at this energy scale. A Large Hadron electron Collider, LHeC, in which an electron (positron) beam of energy (70 to 140 GeV) is in collision with one of the LHC hadron beams, makes possible terascale lepton-hadron physics. The LHeC is presently being evaluated in the form of two options, “ring-ring” and “linac-ring”, either of which operate simultaneously with pp or ion-ion collisions in other LHC interaction regions. Each option takes advantage of recent advances in radio-frequency, in linear acceleration, and in other associated technologies, to achieve ep luminosity as large as 1033 cm-2s-1.
