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.

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 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 development and first results are described of a silicon strip detector telescope for the HERA experiment H1 designed to measure the polar angle of deep inelastic scattered electrons at small Bjorken x and low momentum transfers Q(2).

Technical aspects of the three major components of the H1 detector at the electron-proton storage ring HERA are described. This paper covers the detector status up to the end of 1994 when a major upgrading of some of its elements was undertaken. A description of the other elements of the detector and some performance figures from luminosity runs at HERA during 1993 and 1994 are given in a paper previously published in this journal.

The H1 detector at HERA at DESY presently undergoes a major upgrade. In this context silicon strip detectors have been installed at the beginning of 1995. The high bunch crossing frequency of HERA (10.4 MHz) demands a novel readout architecture which includes pipelining, signal processing and data reduction at a very early stage. The front end readout is hierarchically organized. The detector elements are read out by the APC chip which contains an analog pipeline and performs first background subtraction. Up to five readout chips are controlled by a Decoder Chip. The readout processor module (OnSiRoC) operates the detectors, controls the Decoder Chips and performs a first level data reduction. The paper describes the readout architecture of the H1 silicon detectors and performance data of the complete readout chain.

The H1 detector at the electron proton collider HERA at DESY undergoes at present a major upgrade program. In this context a Silicon Tracking Detector System is under construction. This system consist of a cylindrical vertex type detector around the interaction point (CST) and disk-shaped silicon detectors of different types in the backward (i.e. electron) direction (BST). The readout for the strip detectors is based on a novel front-end readout chip (APC) and a new readout processor (onSiRoC). The readout is pipelined in order to cope with the bunch crossing frequency of 10.6 MHz of HERA. The readout has many features to compress data at the earliest stage. The implementation into the H1 data acquisition is organized using the VMEbus standards and exploiting existing H1 software packages as much as possible.

Summary form only. The authors discuss a study to upgrade the existing H1 tracking detector by a semiconductor backward tracking telescope consisting of eight beam concentric discs to measure the gluon and quark distribution functions at very low Bjorken x. Each disc comprises three planes of strip and pad silicon detectors made of 4-in wafers in order to measure the polar angle and the transverse momentum, and to trigger on deep inelastically scattered electrons. The technical and electronics design of the trigger has to cope with very high beam background rates and the HERA bunch crossing rate of 10.4 MHz.<>

A method is proposed to recognize and resolve double-hit structures in 100 MHz FADC pulses using data taken with prototypes of the cylindrical outer z chamber of the HERA detector H1. With 90% efficiency double hits can be resolved down to distances of about 2.5 mm. The peak position of the second pulse can be reconstructed by subtracting a reference pulse from the signal which is derived from the data themselves. The resolution for perpendicular track crossing is about 250 μm. The method is fast and can be extended to multiple hits (n > 2).

Test measurements were performed with prototypes (full-scale radius and single cells) of the outer z-drift chamber (COZ) of the central tracker of the HERA experiment H1. The COZ consists of a 2.20 m long cylindrical arrangement of rectangular drift cells made of 24 identical rings of 47 cm radius with sense wires strung in a 24-fold polygon around the beam axis. The signals are transmitted via flexible twin lines to the preamplifiers located outside the gas volume at the end flanges. The tests were performed at a DESY test beam using Ar/CH4 and Ar/C3H8 and a 100 MHz FADC readout. Detailed results on the geometric efficiency, resolution and charge division are reported.