A 2D photon-counting X-ray detector system with 1.4 kHz frame rate and 55 µm spatial resolution has been developed and commissionned on ESRF beamlines. The system called MAXIPIX (Multichip Area X-ray detector based on a photon-counting PIXel array) consists of a detector module implementing up to five MEDIPIX-2 or TIMEPIX photon-counting readout chips, a custom readout interface board and a Linux acquisition workstation. The detector module readout time is 290 microseconds, allowing the system to achieve sustained frame rates of 280 Hz to 1400 Hz depending on the number of connected chips. An effective time resolution of 60 ns was measured using the ESRF pulsed modes and a TIMEPIX module. The system architecture and characteristics are presented, as well as a summary of its applications on ESRF beamlines.

ID29 is an ESRF undulator beamline with a routinely accessible energy range of between 20.0 keV and 6.0 keV (= 0.62 Å to 2.07 Å) dedicated to the use of anomalous dispersion techniques in macromolecular crystallography. Since the beamline was first commissioned in 2001, ID29 has, in order to provide an improved service to both its academic and proprietary users, been the subject of almost continuous upgrade and refurbishment. It is now also the home to the ESRF Cryobench facility, ID29S. Here, the current status of the beamline is described and plans for its future are briefly outlined.

Crystals of biological macromolecules often exhibit considerable inter-crystal and intra-crystal variation in diffraction quality. This requires the evaluation of many samples prior to data collection, a practice that is already widespread in macromolecular crystallography. As structural biologists move towards tackling ever more ambitious projects, new automated methods of sample evaluation will become crucial to the success of many projects, as will the availability of synchrotron-based facilities optimized for high-throughput evaluation of the diffraction characteristics of samples. Here, two examples of the types of advanced sample evaluation that will be required are presented: searching within a sample-containing loop for microcrystals using an X-ray beam of 5 microm diameter and selecting the most ordered regions of relatively large crystals using X-ray beams of 5-50 microm in diameter. A graphical user interface developed to assist with these screening methods is also presented. For the case in which the diffraction quality of a relatively large crystal is probed using a microbeam, the usefulness and implications of mapping diffraction-quality heterogeneity (diffraction cartography) are discussed. The implementation of these techniques in the context of planned upgrades to the ESRF's structural biology beamlines is also presented.

For the first time, protein microcrystallography has been performed with a focused synchrotron‐radiation beam of 1 µm using a goniometer with a sub‐micrometre sphere of confusion. The crystal structure of xylanase II has been determined with a flux density of about 3 × 1010 photons s−1 µm−2 at the sample. Two sets of diffraction images collected from different sized crystals were shown to comprise data of good quality, which allowed a 1.5 Å resolution xylanase II structure to be obtained. The main conclusion of this experiment is that a high‐resolution diffraction pattern can be obtained from 20 µm3 crystal volume, corresponding to about 2 × 108 unit cells. Despite the high irradiation dose in this case, it was possible to obtain an excellent high‐resolution map and it could be concluded from the individual atomic B‐factor patterns that there was no evidence of significant radiation damage. The photoelectron escape from a narrow diffraction channel is a possible reason for reduced radiation damage as indicated by Monte Carlo simulations. These results open many new opportunities in scanning protein microcrystallography and make random data collection from microcrystals a real possibility, therefore enabling structures to be solved from much smaller crystals than previously anticipated as long as the crystallites are well ordered.

ID15A is a newly refurbished beamline at the ESRF devoted to operando and time‐resolved diffraction and imaging, total scattering and diffraction computed tomography. The beamline is optimized for rapid alternation between the different techniques during a single operando experiment in order to collect complementary data on working systems. The high available energy (up to 120 keV) means that even bulky and highly absorbing systems may be studied. The beamline is equipped with optimized focusing optics and a photon‐counting CdTe pixel detector, allowing for both unprecedented data quality at high energy and for very rapid triggered experiments. A large choice of imaging detectors and ancillary probes and sample environments is also available.