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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).

High brightness electron sources for linac based free-electron lasers (FELs) are being developed at the Photo Injector Test facility at DESY, Zeuthen site (PITZ). Production of electron bunches with extremely small transverse emittance is the focus of the PITZ scientific program. The photoinjector optimization in 2008–2009 for a bunch charge of 1, 0.5, 0.25, and 0.1 nC resulted in measured emittance values which are beyond the requirements of the European XFEL [S. Rimjaem et al., Nucl. Instrum. Methods Phys. Res., Sect. A 671, 62 (2012)NIMAER0168-900210.1016/j.nima.2011.12.101]. Several essential modifications were commissioned in 2010–2011 at PITZ, resulting in further improvement of the photoinjector performance. Significant improvement of the rf gun phase stability is a major contribution in the reduction of the measured transverse emittance. The old TESLA prototype booster was replaced by a new cut disk structure cavity. This allows acceleration of the electron beam to higher energies and supports much higher flexibility for stable booster operation as well as for longer rf pulses which is of vital importance especially for the emittance optimization of low charge bunches. The transverse phase space of the electron beam was optimized at PITZ for bunch charges in the range between 0.02 and 2 nC, where the quality of the beam measurements was preserved by utilizing long pulse train operation. The experimental optimization yielded worldwide unprecedented low normalized emittance beams in the whole charge range studied.

High brightness electron sources for linac based short-wavelength free-electron lasers are developed and optimized for small transverse projected emittance at the photo-injector test facility at DESY, location Zeuthen (PITZ). A major part of the measurement program at PITZ is dedicated to transverse phase space optimization in order to fulfill the requirements of the European X-ray free-electron laser (European XFEL). A laser-driven RF-gun, treated with a dry-ice sublimation-impulse cleaning technique, a new photocathode laser system allowing short rise and fall times of the flat-top temporal distribution as well as several new diagnostic components have been installed at PITZ in 2008. The electrons generated via the photo-effect at a cesium telluride (Cs2Te) cathode are accelerated by a 1.6 cell L-band RF-gun cavity with a maximum accelerating gradient at the cathode of about 60 MV/m. The transverse projected emittance is measured using a single slit scan technique. In the 2008–2009 run period, a detailed characterization of the projected transverse emittance was performed at different operating conditions. Optimizations and measurement results as well as simulation predictions of the transverse projected emittance for bunch charges of 1, 0.5, 0.25 and 0.1 nC are presented and discussed in this paper. The geometric mean of the normalized projected rms emittance in both transverse directions for an electron bunch charge of 1 nC was measured to be

Recent work has shown the possibility of generating self-shaped ellipsoidal beams with properties commensurate with the requirements of future light sources such as free-electron lasers and inverse Compton sources. In this so-termed ``blowout'' regime, short laser bunches are transformed via photoemission into short electron bunches which then self-consistently evolve into nearly uniform-density ellipsoids under space-charge forces. We report here on the first blowout studies conducted in collaboration between the UCLA Particle Beam Physics Lab and the Photo Injector Test Facility, Zeuthen (PITZ). The measurements conducted at the PITZ photoinjector facility examine the evolution of 750 pC, 2.7 ps FWHM electron bunches born in an L-band photoinjector and subsequently accelerated through a nine-cell L-band booster for a resulting energy of 12 MeV. These measurements represent the first observations of self-shaped ellipsoid evolution under postinjector acceleration, a key step in demonstrating the utility of such self-shaped beams at higher energy, where the advantages in both transverse and longitudinal and transverse phase space may be exploited in creating very high brightness beams.

The photoinjector test facility at DESY, Zeuthen site (PITZ), was built to develop and optimize photoelectron sources for superconducting linacs for high-brilliance, short-wavelength free-electron laser (FEL) applications like the free-electron laser in Hamburg (FLASH) and the European x-ray free-electron laser (XFEL). In this paper, the detailed characterization of two laser-driven rf guns with different operating conditions is described. One experimental optimization of the beam parameters was performed at an accelerating gradient of about 43 MV/m at the photocathode and the other at about 60 MV/m. In both cases, electron beams with very high phase-space density have been demonstrated at a bunch charge of 1 nC and are compared with corresponding simulations. The rf gun optimized for the lower gradient has surpassed all the FLASH requirements on beam quality and rf parameters (gradient, rf pulse length, repetition rate) and serves as a spare gun for this facility. The rf gun studied with increased accelerating gradient at the cathode produced beams with even higher brightness, yielding the first demonstration of the beam quality required for driving the European XFEL: The geometric mean of the normalized projected rms emittance in the two transverse directions was measured to be 1.26±0.13 mm mrad for a 1-nC electron bunch. When a 10% charge cut is applied excluding electrons from those phase-space regions where the measured phase-space density is below a certain level and which are not expected to contribute to the lasing process, the normalized projected rms emittance is about 0.9 mm mrad.

A new L-band photoelectron gun (prototype 3.2) has been installed for use with a 10 MW klystron at the Photo- Injector Test facility in Zeuthen (PITZ). This gun has been conditioned starting in April 2007 up to a maximum gradient of about 60 MV/m. The gun was tuned for resonance at 1.3 GHz, and stable operation has been achieved with 100 mus RF pulses with a repetition rate of 10 Hz. Over certain periods the gun has been conditioned at high gradient with RF pulses of 400 mus, and conditioning has to be continued at longer pulse lengths up to 700 mus. Maximum power in the gun has been achieved with a new RF waveguide phase shifter with a 2pi range. Dark current measurements have been performed with several cathodes, including uncoated molybdenum, electropolished uncoated molybdenum, and cesium telluride. Also, the first photoelectrons have been accelerated with the new gun cavity.

Free electron LASer in Hamburg (FLASH) at DESY is a user facility with laser-like radiation source in the VUV and soft X-ray range. It is also a pilot facility for the future XFEL. A fast data acquisition system (DAQ) to support the accelerator operation and the user experiments was developed. The system collects data from hundreds of ADC channels in the range of 1 M up to 2 G samples per second. In addition it allows collecting images from digital video cameras. All the data is collected in a shared memory of a central multiprocessor computer. Several processes are used to calculate e.g., the orbit, energy or photon flux, or are used as feedback loops to improve the stability of the linac. A long time archiving of the collected data from the accelerator and from the FEL experiments on a 24 TB disk and finally on a tape is provided. The whole system is integrated in the DOOCS control system of FLASH. It is a novel approach to combine a fast DAQ system with a accelerator control system.

The Photo-Injector Test Facility at DESY in Zeuthen (PITZ) is an electron accelerator which was built to develop and optimize high brightness electron sources suitable for SASE FEL operation. Currently, in parallel to the operation of the existing setup, a large extension of the facility and its research program is ongoing. The beam line which has a present length of about 13 meters will be extended up to about 21 meters within the next year. Many additional diagnostics components will be added to the present layout. Two high-energy dispersive arms, an RF deflecting cavity and a phase space tomography module will extend the existing diagnostic system of the photo injector and will contribute to the full characterization of new electron sources. We report on the latest developments of the beam diagnostics at PITZ.

The ability to produce high brightness electron beams as required for modern Free Electron Lasers (FELs) has been demonstrated during the first stage of the Photo Injector Test Facility at DESY Zeuthen (PITZ1). The electron source optimization at PITZ1 was successfully completed, resulting in the installation of the PITZ rf gun at the VUV-FEL (DESY, Hamburg). One of the main goals of the second stage of PITZ (PITZ2) is to apply higher gradients in the rf gun cavity in order to obtain smaller beam emittance by faster acceleration of the space charge dominated beams. In order to reach the required gradients a 10 MW klystron has to be installed and the gun cavity has to be conditioned for higher peak power. Another important goal of PITZ2 is a detailed study of the emittance conservation principle by using proper electron beam acceleration with a booster. Further photo injector optimization, including update of the photocathode laser and diagnostic tools, is foreseen as well. Recent progress on the PITZ developments will be reported.