The European XFEL is a hard X-ray free-electron laser (FEL) based on a high-electron-energy superconducting linear accelerator. The superconducting technology allows for the acceleration of many electron bunches within one radio-frequency pulse of the accelerating voltage and, in turn, for the generation of a large number of hard X-ray pulses. We report on the performance of the European XFEL accelerator with up to 5,000 electron bunches per second and demonstrating a full energy of 17.5 GeV. Feedback mechanisms enable stabilization of the electron beam delivery at the FEL undulator in space and time. The measured FEL gain curve at 9.3 keV is in good agreement with predictions for saturated FEL radiation. Hard X-ray lasing was achieved between 7 keV and 14 keV with pulse energies of up to 2.0 mJ. Using the high repetition rate, an FEL beam with 6 W average power was created. The first operation of the European X-ray free-electron laser facility accelerator based on superconducting technology is reported. The maximum electron energy is 17.5 GeV. A laser average power of 6 W is achieved at a photon energy of 9.3 keV.

The Photo Injector Test facility at DESY, Zeuthen site (PITZ), develops, optimizes and characterizes high brightness electron sources for free electron lasers like FLASH and the European XFEL. In the last year, the PITZ facility was significantly upgraded by the installation of a new normal conducting radio-frequency (RF) gun cavity with its new waveguide system for the RF feed, which should allow stable and reliable gun operation, as required for the European XFEL. Other relevant additions include beamline modifications for improving the electron beam transport through the PITZ accelerator and preparing the installation of a plasma cell. Furthermore, the laser hutch was re-arranged in order to house an additional, new photo cathode drive laser system which will produce 3D ellipsoidal laser pulses to further improve the electron beam quality. This paper describes the facility upgrades and reports on the first operation experience with the new gun setup.

For successful operation of X-ray Free Electron Lasers, one crucial parameter is the ultrashort electron bunch length yielding a high peak current and a short saturation length. In order to effectively compress the bunches during the acceleration process, a detailed understanding of the full longitudinal phase space distribution already in the injector is required. Transverse deflecting RF structures (TDS) can shear the bunch transversely, mapping the longitudinal coordinate to a transverse axis on an observation screen downstream. In addition to the bunch length, the slice emittance along the bunch as well as the full longitudinal phase space can be obtained. At the Photo Injector Test Facility at DESY, Zeuthen site (PITZ), an S-band traveling wave TDS is under commissioning since 2015. This cavity is a prototype for the TDS in the injector part of the European XFEL and has been designed and manufactured by the Institute for Nuclear Research (INR RAS, Moscow, Russia). In this paper, first commissioning results of the system at PITZ are presented and discussed.

The data collected by the L3+C muon spectrometer at the CERN Large ElectronPositron collider, LEP, have been used to search for short duration signals emitted by cosmic point sources. A sky survey performed from July to November 1999 and from April to November 2000 has revealed one single flux enhancement (chance probability = 2.6·10) between the 17th and 20th of August 2000 from a direction with a galactic longitude of (265.02 ± 0.42) and latitude of (55.58 ± 0.24). The energy of the detected muons was above 15 GeV. Reference: Astroparticle Physics, 33 (2010 )24 − 39

The Photo Injector Test facility at DESY, Zeuthen site (PITZ), is dedicated to develop and optimize high brightness electron sources for short wavelength FreeElectron Lasers (FELs) like FLASH and the European XFEL, both in Hamburg (Germany). Since October 2009 a major upgrade is ongoing with the goal to improve the accelerating components, the photocathode drive laser system and the beam diagnostics as well. The essential new feature in the running will be an in-vacuum 10 MW RF directional coupler to be used for the RF monitoring and control. In this context a significant improvement of the RF stability is expected. RF pulses of 800 microseconds with 10 Hz repetition rate will be used. The most important upgrade of the diagnostics system will be the implementation of a phase space tomography module (PST) consisting of three FODO cells each surrounded by two screen stations. The goal is an improved measurement of the transverse phase space at different charge levels. The upgraded facility will be described.

The data collected by the L3+C muon spectrometer at the CERN Large Electron-Positron collider, LEP, have been used to search for short duration signals emitted by cosmic point sources. A sky survey performed from July to November 1999 and from April to November 2000 has revealed one single flux enhancement (chance probability = 2.6 x 10(-3)) between the 17th and 20th of August 2000 from a direction with a galactic longitude of (265.02 +/- 0.42)degrees and latitude of (55.58 +/- 0.24)degrees. The energy of the detected muons was above 15 GeV. (C) 2009 Elsevier B.V. All rights reserved.

The DESY PITZ booster cavity, based on the Cut Disk Structure (CDS), is completed in construction. The L-band normal conducting cavity is intended to operate with accelerating gradient up to 14 MV m and RF pulse length up to 900μs to increase the electron bunch energy in the PITZ facility by ∼ 20 Me V. The cavity was vacuum conditioned to reduce the out-gassing rate for operation in the facility with photo cathodes. The cavity is mounted in the PITZ tunnel and RF conditioning has started. The results of RF tuning before and after cavity brazing together with first results of conditioning are presented.

Transverse Deflecting Systems are designated for longitudinal beam diagnostics of ultra-short electron bunches in modern FEL projects. At the European XFEL, Transverse Deflecting Systems are foreseen at three locations. A prototype of the TDS in the injector of the European XFEL will be installed at PITZ, which is identical in terms of deflecting structure, low-level RF system and powerful RF hardware. This PITZ TDS has the aim to prove the required performance for all TDS subsystems as well as serve as a diagnostics tool for PITZ. Results of the test cells measurements of a S-band traveling wave structure are presented, showing very good agreement with calculated parameters. RF power supply system, including a 3 MW klystron and other RF hardware, is described. Solid state 130 kV Marx modulator has been developed for the klystron feeding. 10 kV module of the modulator has been built and tested. The modulator allows for high voltage shutdown within pulse.

The main task of the interlock system is to prevent any damage of the costly components of the RF station. The implementation of the interlock must also guarantee a maximum uninterrupted time of operation which implies the implementation of self diagnostics and repair strategies on a modular basis. Additional tasks include collection and temporary storage of status information of individual channels; transfer of this information to the higher level control system, and also the implementation of slow control functions. The interlock system incorporates a controller with several slave modules for I/O processing. It implements the interlock function as hardwired logic (within a FPGA) and contains a softcore processor for higher level tasks. The software performs a system-test on power-up to check the hardware functionality and the crate configuration. On success, the interlock hardware is configured for continuous operation. The architecture of the interlock system provides the fast processing of the incoming data and reaction in real time required for machine- and component-protection. Special fast front-end I/O and slave modules have been developed to achieve the timing requirements. In addition slow input signals without fast timing requirements are also processed by the central node of the interlock. For the processing of these signals there exist products on the market which are less expensive, already developed, easier to maintain, and have a long market history in comparison to our in-house solution. The integration of industrial products is possible by using a standard fieldbus protocol. For example, a possible solution based on a real time Ethernet fieldbus will be discussed. It is implemented with an "EtherCAT" master providing the I/O extension to the interlock system for industrial components.

Context. Primary cosmic rays experience multiple deflections in the non-uniform galactic and heliospheric magnetic fields which may generate anisotropies.Aims. A study of anisotropies in the energy range between 100 and 500 GeV is performed. This energy range is not yet well explored.Methods. The L3 detector at the CERN electron-positron collider, LEP, is used for a study of the angular distribution of atmospheric muons with energies above 20 GeV. This distribution is used to investigate the isotropy of the time-dependent intensity of the primary cosmic-ray flux with a Fourier analysis.Results. A small deviation from isotropy at energies around 200 GeV is observed for the second harmonics at the solar frequency. No sidereal anisotropy is found at a level above 10(-4). The measurements were performed in the years 1999 and 2000.

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 main task of the interlock system is to prevent any damage to the cost expensive components of the RF station. The implementation of the interlock should guarantee a maximum of uninterrupted time of operation which includes the implementation of self diagnostic and repair strategies on module basis. Additional tasks include collection and temporary storage of status information of individual channels; transfer of this information to a higher level control system, but also the enactment of slow control functions. The interlock implementation is based on a 4U 19"-Crate which houses a controller and different slave modules which implement the interface to the components of the RF station. A dedicated, user defined backplane connects the controller to all slave modules. The Controller incorporates a 32-bit RISC NIOS-II processor inside a Cyclone-II FPGA device from ALTERA. The program running on this processor performs all necessary control and monitoring functions to all slave modules in the crate, but not the interlock function itself. The interlock function is implemented as hardwired logic and keeps working, even if the processor stops or the program hangs up. The software performs a system-test on power-up, to test the hardware functionality and the crate configuration. On success, the interlock hardware gets configured for operation and the crate is put into the working state. After initialization higher level applications get loaded. This covers the communication interface to the control system and a diagnostic interface, which is used during installation and trouble shooting. For this purpose, LabVIEW tools are used to present information. In addition, a HTTP server on the interlock controller provides the possibility to change configuration and view actual status information. It also implements tools which allow to reconfigure the whole FPGA design or to upload a new software version via Ethernet.

Aims. Several experiments have reported observations on possible correlations between the flux of high energy muons and intense solar flares. If confirmed, these observations would have significant implications for acceleration processes in the heliosphere able to accelerate protons and other ions to energies of at least tens of GeV.Methods. The solar flare of the 14 of July 2000 offered a unique opportunity for the L3+C experiment to search for a correlated enhancement in the flux of muons using the L3 precision muon spectrometer. Its capabilities for observing a directional excess in the flux of muons above 15 GeV (corresponding to primary proton energies above 40 GeV) are presented along with observations made on the 14th of July 2000.Results. We report an excess which appeared at a time coincident with the peak increase of solar protons observed at lower energies. The probability that the excess is a background fluctuation is estimated to be 1%. No similar excess of the muon flux was observed up to 1.5 h after the solar flare time.