The new European X-ray Free-Electron Laser is the first X-ray free-electron laser capable of delivering X-ray pulses with a megahertz inter-pulse spacing, more than four orders of magnitude higher than previously possible. However, to date, it has been unclear whether it would indeed be possible to measure high-quality diffraction data at megahertz pulse repetition rates. Here, we show that high-quality structures can indeed be obtained using currently available operating conditions at the European XFEL. We present two complete data sets, one from the well-known model system lysozyme and the other from a so far unknown complex of a β-lactamase from K. pneumoniae involved in antibiotic resistance. This result opens up megahertz serial femtosecond crystallography (SFX) as a tool for reliable structure determination, substrate screening and the efficient measurement of the evolution and dynamics of molecular structures using megahertz repetition rate pulses available at this new class of X-ray laser source.

A description of the 1 million pixel AGIPD system in use at the SPB beamline of the European XFEL is given.

The two-dimensional pixel detector JUNGFRAU is designed for high performance photon science applications at free electron lasers and synchrotron light sources. It is developed for the SwissFEL currently under construction at the Paul Scherrer Institut, Switzerland. The detector is a hybrid pixel detector with a charge integration readout ASIC characterized by single photon sensitivity and a low noise performance over a dynamic range of 10 4 12 keV photons.Geometrically, a JUNGFRAU readout chip consists of 256×256 pixels of 75×75 µm 2 . The chips are bump bonded to 320 µm thick silicon sensors. Arrays of 2×4 chips are tiled to form modules of 4×8 cm 2 area. Several multi-module systems with up to 16 Mpixels per system will be delivered to the two end stations at SwissFEL.The JUNGFRAU full scale readout ASIC and module design are presented along with characterization results of the first systems. Experiments from fluorescence X-ray, visible light illumination, and synchrotron irradiation are shown. The results include an electronic noise of ∼50 electrons r.m.s., which enables single photon detection energies below 2 keV and a noise well below the Poisson statistical limit over the entire dynamic range. First imaging experiments are also shown.

The SwissFEL, a free electron laser (FEL) based next generation X-ray source, is being built at PSI. An XFEL poses several challenges to the detector development: in particular the single photon counting readout, a successful scheme in case of synchrotron sources, can not be used. At the same time the data quality of photon counting systems, i.e. the low noise and the high dynamic range, is essential from an experimental point of view.Detectors with these features are under development for the EU-XFEL in Hamburg, with the PSI SLS Detector group being involved in one of these efforts (AGIPD). The pulse train time structure of the EU-XFEL machine forces the need of in pixel image storage, resulting in pixel pitches in the 200 µm range. Since the SwissFEL is a 100 Hz repetition rate machine, this constrain is relaxed. For this reason, PSI is developing a 75 µm pitch pixel detector that, thanks to its automatic gain switching technique, will achieve single photon resolution and a high dynamic range. The detector is modular, with each module consisting of a 4×8 cm 2 active sensor bump bonded to 8 readout ASICs (Application Specific Integrated Circuit), connected to a single printed circuit readout board with 10GbE link capabilities for data download.We have designed and tested a 48 × 48 pixel prototype produced in UMC110 nm technology. In this paper we present the general detector and ASIC design as well as the results of the prototype characterization measurements.

AGIPD -(Adaptive Gain Integrating Pixel Detector) is a hybrid pixel X-ray detector developed by a collaboration between Deutsches Elektronen-Synchrotron (DESY), Paul-ScherrerInstitut (PSI), University of Hamburg and the University of Bonn. The detector is designed to comply with the requirements of the European XFEL. The radiation tolerant Application Specific Integrated Circuit (ASIC) is designed with the following highlights: high dynamic range, spanning from single photon sensitivity up to 10 4 12.5keV photons, achieved by the use of the dynamic gain switching technique using 3 possible gains of the charge sensitive preamplifier. In order to store the image data, the ASIC incorporates 352 analog memory cells per pixel, allowing also to store 3 voltage levels corresponding to the selected gain. It is operated in random-access mode at 4.5MHz frame rate. The data acquisition is done during the 99.4ms between the bunch trains. The AGIPD has a pixel area of 200×200 µm 2 and a 500µm thick silicon sensor is used. The architecture 1 Corresponding author. 2015 JINST 10 C01023 principles were proven in different experiments and the ASIC characterization was done with a series of development prototypes. The mechanical concept was developed in the close contact with the XFEL beamline scientists and is now being manufactured. A first single module system was successfully tested at APS.