Application of 3D ellipsoidal cathode laser
Deutsches Elektronen-Synchrotron DESY
Partner in Russland:
Institute of Applied Physics and
Joint Instiute for Nuclear Research
The Photo Injector test facility at DESY, Zeuthen site (PITZ), wants to further extend its leading position in the development of high brightness electron sources for free electron lasers (FELs) by further advancing in the photo cathode laser development. The major application of these efforts is the European XFEL which is under construction at DESY in Hamburg now. More than one decade of continuous development and experience at PITZ shows that the cathode laser pulse shaping is one of the key issues for the photo injector performance. A cathode laser system capable of producing pulses with a flat-top temporal profile of ~20ps FWHM is right now in operation. A very
high electron beam quality was experimentally demonstrated at PITZ applying this cathode laser. However, beam dynamics simulations applying a 3D ellipsoidal cathode laser pulses predict further significant improvements of the photo electron beam quality, namely more than 30% projected emittance reduction, smaller electron beam halo and less nonlinear longitudinal phase space. The BMBF project “Developing a laser system for experimentally investigating the possibility to achieve quasi 3D ellipsoidal laser pulses” was started in 2009 and aims for a joint research project on theoretical and experimental investigations of a photo injector laser system with a pulse shaper for achieving quasi 3D ellipsoidal laser pulses. The project is on-going, several important milestones were reached and new crucial issues were revealed. This new proposal aims to study these revealed features as well as new applications of the cathode laser system under development. The most
important aspects are:
-Optimizing the 4th harmonics generation of the 3D shaped pulses including thermal effects in the
conversion crystals due to the European XFEL pulse train structure: up to 650 pulses in a pulse train of 1…4.5MHz pulse spacing and 10Hz train repetition rate.
-Further improvement of 3D shaped laser pulses, especially in the transverse plane. Besides various experimental tests this item also includes simulation studies of shape imperfection impact onto the expected electron bunches properties like laser pulse border sharpness and rotational asymmetry.
-Study a possibility of applying 3D laser pulses for producing very short electron bunches (~ 10fs) and their further application to advanced acceleration techniques, like wakefield acceleration with external injection.
-More detailed photo emission studies on generating self-consistent 3D electron ellipsoidal bunches by taking into account space charge effects in the cathode vicinity, including cathode laser pulse pre-deformation.
-Design and development of a transport beamline for 3D shaped laser pulses with a typical distance
-Extension of the PITZ experimental diagnostics for 3D electron bunches with time resolution of the
temporal electron bunch shape towards 0.2…0.3ps
-Efforts for parallel operation of two photo cathode laser systems at PITZ, including synchronization
In a common effort young German and Russian researches will develop and use new innovative techniques. Under the guidance of experienced researchers in the field, promising young scientists will advance these new technologies and will apply them for the first time in the environment of a world leading existing facility.
Coordination at DESY:
Dr. Mikhail Krasilnikov
Tel.: +49 337627-7213