New PITZ Results - Important progress for the European XFEL
End of August, a successful period of operation at PITZ (Photo Injector Test facility in Zeuthen) has been concluded.
An important goal of this year’s operation period were measurements of electron beam parameters at increased accelerating gradients of approx. 60 MV/m at the cathode. Beam dynamics simulations promise an improved electron beam quality for this case. The experimental optimization of the so called emittance, a measure of the bundling and parallelism of the electrons, was carried out at PITZ this summer and effectively resulted in an improved beam quality. In both transversal planes, a normalized projected emittance of approx. 1.26 ± 0.19 mm mrad was measured. Discarding a part of the electrons that presumably will not contribute to the lasing of the XFEL yields an emittance as low as approx. 0.8 mm mrad.
So far, these results constitute the smallest measured emittance at a charge of one nanocoulomb (equivalent to 6.3 billion electrons). They are an important step on the way to fulfil the specifications for the European XFEL.
During the current PITZ shutdown, additional measures will be carried out for the improvement of the electron source, e.g. an upgrade of the cathode laser and an extension of the electron beam diagnostics.