[en] Methods for the spatio-temporal shaping of photocathode laser pulses for generating high brightness electron beams in modern linear accelerators are discussed. The possibility of forming triangular laser pulses and quasi-ellipsoidal structures is analyzed. The proposed setup for generating shaped laser pulses was realised at the Institute of Applied Physics (IAP) of the Russian Academy of Sciences (RAS). Currently, a prototype of the pulse-shaping laser system is installed at the Photo Injector Test facility at DESY, Zeuthen site (PITZ). Preliminary experiments on electron beam generation using ultraviolet laser pulses from this system were carried out at PITZ, in which electron bunches with a 0.5-nC charge and a transverse normalized emittance of 1.1 mm mrad were obtained. A new scheme for the three-dimensional shaping of laser beams using a volume Bragg profiled grating is proposed at IAP RAS and is currently being tested for further electron beam generation experiments at the PITZ photoinjector. (conferences and symposia)

[en] The use of high brightness electron beams in Free Electron Laser (FEL) applications is of increasing importance. One of the most promising methods to generate such beams is the usage of shaped photocathode laser pulses. It has already demonstrated that temporal and transverse flat-top laser pulses can produce very low emittance beams [1]. Nevertheless, based on beam simulations further improvements can be achieved using quasi-ellipsoidal laser pulses, e.g. 30% reduction in transverse projected emittance at 1 nC bunch charge. In a collaboration between DESY, the Institute of Applied Physics of the Russian Academy of Science (IAP RAS) in Nizhny Novgorod and the Joint Institute of Nuclear Research (JINR) in Dubna such a laser system capable of producing trains of laser pulses with a quasi-ellipsoidal distribution, has been developed. The prototype of the system was installed at the Photo Injector Test facility at DESY in Zeuthen (PITZ) and is currently in the commissioning phase. In the following, the laser system will be introduced, the procedure of pulse shaping will be described and the last experimental results will be shown.

[en] The matching of a particle beam to specific transverse parameters, imposed by various operational, functional and diagnostic reasons, is an essential procedure in most types of accelerators. While well-established methods can easily match beams of negligible self fields, their accuracy is significantly reduced in the presence of strong space-charge forces. In a pursuit of time-efficient matching solutions for space-charge influenced beams, two approaches are demonstrated in this paper: a faster and more approximative one for symmetric beam transport along periodic and dense lattices, and a more analytic one for broader beam and lattice conditions. Beam dynamics simulations and experimental measurements are used to validate the performance of the suggested methods for the matching requirements of the transverse phase–space tomography at the Photo Injector Test Facility at DESY, Zeuthen site (PITZ). - Highlights: • Two techniques are proposed for the transverse beam matching with linear space charge. • Instant results are obtained for periodic and dense lattices using conventional codes. • Quick results can be obtained for irregular lattices using a home-developed code. • Simulations and measurements demonstrate accuracy and time-efficiency.