Correction to: Clinical recommendations for cardiovascular magnetic resonance mapping of T1, T2, T2* and extracellular volume: A consensus statement by the Society for Cardiovascular Magnetic Resonance (SCMR) endorsed by the European Association for Cardiovascular Imaging (EACVI).

CORRECTION TO: J CARDIOVASC MAGN RESON (2017) 19: 75. DOI: 10.1186/S12968-017-0389-8: In the original publication of this article [1] the "Competing interests" section was incorrect. The original publication stated the following competing interests

Versatile OPCPA Pump-Probe Laser System for the FLASH2 XUV FEL Beamline at DESY

FLASH is currently the worldwide only high repetition-rate XUV and soft X-ray free-electron laser (FEL)facility, consisting of two simultaneously operating undulator beamlines FLASH1 and FLASH2 [1]. Here wereport on the addition of a highly flexible, high repetition-rate femtosecond laser system for pump-probeexperiments at the FLASH2 beamline. The laser system is based on optical parametric chirped pulse amplification (OPCPA) technology. We use ahybrid Yb:fiber-laser – Yb:YAG-Innoslab laser system as OPCPA pump- and supercontinuum generation inYAG as OPCPA seed pulses. The seed-oscillator is synchronized to the FLASH master oscillator via fiberopticlinks to 500 μJ is obtained routinely before beam transport and compression using broad-band double chirpedmirror pairs (DCMs) applying -175 fs²/bounce. Further repetition rate capabilities up-to 1 MHz will be added ongradually during the next years in a modular design concept optimized to minimize tuning times. The laser pulses are currently transported to two FLASH2 experimental end-stations via a more than 40 mlong relay-imaging transport beamline featuring an excellent temporal and spatial stability. At each end-stationmodular optical delivery stations (MODs) are installed for pulse diagnostics, pulse compression, attenuation andfocusing to the experimental chamber. In future, those will host also nonlinear wavelength conversion set-ups forflexible laser – XUV / soft X-ray pump probe schemes.In a first preliminary experiment we delivered 0.8 ms bursts, 100 fs. The central wavelength of theoutput spectrum is remote controlled tunable over a spectral range from 700 nm to 900 nm. Fig. 1 (b) illustratesthe dynamics of those tuning capabilities: The system settles to above described highly wavelength stable outputwithin 10s of seconds after a tuning command.In conclusion we developed and installed a high-repetition rate pump-probe laser system at the FLASH2 –FEL facility delivering > 500μJ < 15fs pulses at 50 kHz repetition rate in 800μs bursts, repeating every 100ms

A MHz-repetition-rate hard X-ray free-electron laser driven by a superconducting linear accelerator

International audienceThe 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