BNL, Upton, Long Island, New York
LBNL, Berkeley, California
Optical stochastic cooling for the Relativistic Heavy Ion Collider (RHIC) based on optical parametric amplification was proposed by M. Babzien et al., Phys. Rev. ST Accel. Beams v.7, 012801, (2004). According to this proposal a CdGeAs2 nonlinear crystal is used as an active medium for the optical parametric amplifier because of extremely large nonlinear coefficient, wide transparency range, and possibility to be phase matched over the required spectral range. We discuss experimental results of the parametric amplifier gain and coherency for the conditions applicable to optical stochastic cooling for RHIC.
LBNL, Berkeley, California
PSI, Villigen
Nano-tips with high acceleration gradient around the emission surface have been proposed to generate high brightness beams. However, due to the small size of the tip, the charge density near the tip is very high even for a small number of electrons. The Coulomb scattering near the tip can significantly degrade the beam quality and cause extra emittance growth and energy spread. In the paper, we present a numerical study of these effects using a direct relativistic N-body model. We found that emittance growth and energy spread, due to Coulomb scattering, can be significantly enhanced with respect to mean-field space-charge calculations in different parameter regimes.
LBNL, Berkeley, California
INFN/LNF, Frascati (Roma)
SLAC, Menlo Park, California
By analysing the pulse to pulse intensity fluctuations of the radiation emitted by a charge particle in the incoherent part of the spectrum, it is possible to extract information about the spatial distribution of the beam. At the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory, we have developed and tested a simple scheme based on this principle that allows for the absolute measurement of the bunch length. A description of the method and the experimental results are presented.
SLAC, Menlo Park, California
DESY, Hamburg
LBNL, Berkeley, California
The Linac Coherent Light Source (LCLS) is a SASE x-ray free-electron laser project presently under construction at SLAC. The injector section from RF photocathode gun through the first bunch compressor chicane was installed during the Fall of 2006. The first bunch compressor chicane is located at 250 MeV and nominally compresses a 1-nC electron bunch from an rms length of about 1 mm to 0.2 mm. The degree of compression is highly adjustable using RF phasing and also chicane magnetic field variations. Transverse phase space and bunch length diagnostics are located immediately after the chicane. We present measurements and simulations of the longitudinal and transverse phase space after the chicane in various beam conditions, including extreme compression where coherent radiation effects are expected to be striking.