New multiGauss distribution
In the cathode at the Argonne Wakefield Accelerator they have the ability to produce microbunched electron bunches, thanks to a laser beam which has a train of Gaussian pulses. Temporal Laser Pulse Shaping for RF Photocathode Guns
At the moment there is no OPAL distribution to reproduce this.
Here is an example with 4 Gaussian microbunches separated (peak-to-peak) by 1.26 mm:
Dist: DISTRIBUTION, TYPE = MULTIGAUSS, SIGMAPX = 1e-2, SIGMAPY = 1e-2, SIGMAPZ = 1e-2, // In units of betaGamma CUTOFFPX = 4.0, CUTOFFPY = 4.0, CUTOFFPZ = 4.0, // In units of SIGMAP SIGMAR = 340e-6, SIGMAZ = .9e-3 / 2.355, // FWHM = 2.355 * sigma CUTOFFLONG = 4.0, // In units of SIGZ SEPPEAKS = 1.26e-3, NPEAKS = 4, EMITTED = FALSE;
In the case where the bunch is emitted, SIGMAPX/Y/Z and CUTOFFPX/Y/Z are omitted, and SIGMAZ and SEPPEAKS are to be given in seconds.