[en] A few open questions in the experimental QCD programme at the ep collider HERA are discussed warranting the extended studies planned at the upgraded accelerator. The large momentum transfers accessible will enable searches for Physics beyond the Standard Model and competitive electroweak consistency checks. The fate of remaining low statistics experimental puzzles from the existing data samples will be resolved. The status of the upgrade of the collider is presented

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[en] Laser-wakefield acceleration has experienced growing scientific interest and fast development during the last decade. Short and highly intense laser pulses focused into a gas target, ionise the gas and may excite large amplitude, co-propagating plasma waves that support extreme electric fields (>10 GV/m) for acceleration of charged particles. These fields are orders of magnitude larger than in conventional radio-frequency accelerators. The REGAE facility at DESY offers the unique possibility to study the external injection of pre-accelerated electron bunches from a stable and fully controlled conventional accelerator, and their subsequent acceleration in plasma wakefields. A set of 2- and 3-dimensional numerical simulations was performed with the particle-in-cell code OSIRIS, showing a wide variety of effects which will be possible to explore in the future with REGAE, which provides 2-5 MeV electron bunches of 10 femtosecond length. Topics of particular interest are: probing of the electric wakefields, emittance evolution, bunch compression, and controlled betatron radiation emission.

[en] Superconducting radio-frequency (SRF) cavities are the key components of particle accelerators such as the European X-ray Free Electron Laser (XFEL, under construction) and the planned future International Linear Collider (ILC). Steady progress in surface treatment techniques of SRF cavities in both the achievable quality factor Q and the accelerating electric field Eacc makes new accelerators and ambitious projects feasible. One of the alternative surface preparation techniques which is actually being explored is centrifugal barrel polishing (CBP) pioneered at KEK in Japan in mid-nineties by T. Hiuchi et al. CBP is a mechanical polishing of cavities and results in around 10 x smaller surface roughness and mirror-like surface as compared to chemistry alone. Q and E_acc are expected to be at least as high as for chemically treated cavities. CBP eliminates the bulk chemistry and has the potential to completely replace the chemistry. The University of Hamburg is installing a CBP machine to study it as a cavity preparation and repair technique for 9-cell 1.3 GHz SRF cavities at the Deutsche Elektronen-Synchrotron (DESY). The setup and first commissioning tests will be presented and discussed.

[en] Precise localization and understanding of local thermal breakdowns or 'quenches' in 9-cell 1.3 GHz superconducting RF cavities are important steps in improving the performance of cavities, such as for the production of cavities for the European XFEL or the planned International Linear Collider. The 2nd sound method is a threshold technique that utilizes the phase transition of superfluid Helium induced during a quench and detected in Oscillating Superleak Transducers (OST). With several OSTs employed typical resolutions of 1cm and better have been obtained. The number and position of sensors has to be optimized. The results are compared with a resistor-based temperature mapping system. Identified quench locations can be inspected for defects using the optical inspection system (OBACHT). Test results of several cavities will be shown.