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The Biomedical Imaging and Therapy facility of the Canadian Light Source comprises two beamlines, which together cover a wide X‐ray energy range from 13 keV up to 140 keV. The beamlines were designed with a focus on synchrotron applications in preclinical imaging and veterinary science as well as microbeam radiation therapy. While these remain a major part of the activities of both beamlines, a number of recent upgrades have enhanced the versatility and performance of the beamlines, particularly for high‐resolution microtomography experiments. As a result, the user community has been quickly expanding to include researchers in advanced materials, batteries, fuel cells, agriculture, and environmental studies. This article summarizes the beam properties, describes the endstations together with the detector pool, and presents several application cases of the various X‐ray imaging techniques available to users. The current state of the Biomedical Imaging and Therapy beamlines of the Canadian Light Source is described and new capabilities are presented.

Unravelling the interaction of biological macromolecules with ligands and substrates at high spatial and temporal resolution remains a major challenge in structural biology. The development of serial crystallography methods at X-ray free-electron lasers and subsequently at synchrotron light sources allows new approaches to tackle this challenge. Here, a new polyimide tape drive designed for mix-and-diffuse serial crystallography experiments is reported. The structure of lysozyme bound by the competitive inhibitor chitotriose was determined using this device in combination with microfluidic mixers. The electron densities obtained from mixing times of 2 and 50 s show clear binding of chitotriose to the enzyme at a high level of detail. The success of this approach shows the potential for high-throughput drug screening and even structural enzymology on short timescales at bright synchrotron light sources.

Detecting microsecond structural perturbations in biomolecules has wide relevance in biology, chemistry and medicine. Here we show how MHz repetition rates at X-ray free-electron lasers can be used to produce microsecond time-series of protein scattering with exceptionally low noise levels of 0.001%. We demonstrate the approach by examining Jɑ helix unfolding of a light-oxygen-voltage photosensory domain. This time-resolved acquisition strategy is easy to implement and widely applicable for direct observation of structural dynamics of many biochemical processes. The MHz repetition rates available at second-generation X-ray free-electron lasers enable the collection of microsecond time-resolved X-ray scattering data with exceptionally low noise, providing insights into protein structural dynamics.

Microcrystals are transforming structural biology by enabling high-resolution structures and time-resolved insights from samples once deemed too small. This commentary highlights recent advances in microfocus X-ray and MicroED methods, emphasizing their growing role as powerful and complementary tools in modern macromolecular crystallography.

Crystallization is a fundamental non-equilibrium process in materials science, yet its early transient states remain difficult to probe experimentally. Möller et al. [(2025). IUCrJ 12, 462-471] use femtosecond X-ray scattering and X-ray cross-correlation analysis to reveal the structural evolution of defect-containing crystals forming in a supercooled noble-gas liquid.

High-quality total scattering data, a key tool for understanding atomic-scale structure in disordered materials, require stable instrumentation and access to high momentum transfers. This is now routine at dedicated synchrotron instrumentation using high-energy X-ray beams, but it is very challenging to measure a total scattering dataset in less than a few microseconds. This limits their effectiveness for capturing structural changes that occur at the much faster timescales of atomic motion. Current X-ray free-electron lasers (XFELs) provide femtosecond-pulsed X-ray beams with maximum energies of ∼24 keV, giving the potential to measure total scattering and the attendant pair distribution functions (PDFs) on femtosecond timescales. We demonstrate that this potential has been realized using the HED scientific instrument at the European XFEL and present normalized total scattering data for 0.35 Å −1 < Q < 16.6 Å −1 and their PDFs from a broad spectrum of materials, including crystalline, nanocrystalline and amorphous solids, liquids and clusters in solution. We analyzed the data using a variety of methods, including Rietveld refinement, small-box PDF refinement, joint reciprocal–real-space refinement, cluster refinement and Debye scattering analysis. The resolution function of the setup is also characterized. We conclusively show that high-quality data can be obtained from a single ∼30 fs XFEL pulse for multiple different sample types. Our efforts not only significantly increase the existing maximum reported Q range for an S ( Q ) measured at an XFEL but also mean that XFELs are now a viable X-ray source for the broad community of people using reciprocal-space total scattering and PDF methods in their research.

Fixed targets are a popular form of sample-delivery system used in serial crystallography at synchrotron and X-ray free-electron laser sources. They offer a wide range of sample-preparation options and are generally easy to use. The supports are typically made from silicon, quartz or polymer. Of these, currently, only silicon offers the ability to perform an aperture-aligned data collection where crystals are loaded into cavities in precise locations and sequentially rastered through, in step with the X-ray pulses. The polymer-based fixed targets have lacked the precision fabrication to enable this data-collection strategy and have been limited to directed-raster scans with crystals randomly distributed across the polymer surface. Here, the fabrication and first results from a new polymer-based fixed target, the micro-structured polymer fixed targets (MISP chips), are presented. MISP chips, like those made from silicon, have a precise array of cavities and fiducial markers. They consist of a structured polymer membrane and a stabilization frame. Crystals can be loaded into the cavities and the excess crystallization solution removed through apertures at their base. The fiducial markers allow for a rapid calculation of the aperture locations. The chips have a low X-ray background and, since they are optically transparent, also allow for an a priori analysis of crystal locations. This location mapping could, ultimately, optimize hit rates towards 100%. A black version of the MISP chip was produced to reduce light contamination for optical-pump/X-ray probe experiments. A study of the loading properties of the chips reveals that these types of fixed targets are best optimized for crystals of the order of 25 µm, but quality data can be collected from crystals as small as 5 µm. With the development of these chips, it has been proved that polymer-based fixed targets can be made with the precision required for aperture-alignment-based data-collection strategies. Further work can now be directed towards more cost-effective mass fabrication to make their use more sustainable for serial crystallography facilities and users.

Many soft-matter systems are composed of macromolecules or nanoparticles suspended in water. The characteristic times at intrinsic length scales of a few nanometres fall therefore in the microsecond and sub-microsecond time regimes. With the development of free-electron lasers (FELs) and fourth-generation synchrotron light-sources, time-resolved experiments in such time and length ranges will become routinely accessible in the near future. In the present work we report our findings on prototypical soft-matter systems, composed of charge-stabilized silica nanoparticles dispersed in water, with radii between 12 and 15 nm and volume fractions between 0.005 and 0.2. The sample dynamics were probed by means of X-ray photon correlation spectroscopy, employing the megahertz pulse repetition rate of the European XFEL and the Adaptive Gain Integrating Pixel Detector. We show that it is possible to correctly identify the dynamical properties that determine the diffusion constant, both for stationary samples and for systems driven by XFEL pulses. Remarkably, despite the high photon density the only observable induced effect is the heating of the scattering volume, meaning that all other X-ray induced effects do not influence the structure and the dynamics on the probed timescales. This work also illustrates the potential to control such induced heating and it can be predicted with thermodynamic models.

We demonstrate an advanced scattering method for accessing the 3D reciprocal space of crystalline structures forming in a rapidly supercooled noble-gas liquid using a combination of femtosecond X-ray diffraction and X-ray cross-correlation analysis. The preservation of angular information from the scattering signal allows probing the structure factor along selected directions in reciprocal space and identifying signatures undetectable in azimuthally integrated scattering curves. Therefore, more information from serial diffraction experiments on stochastic crystallization processes can be retrieved despite the inherent variation of the crystal orientation and morphology for each single probe. We also demonstrate how different features in the correlation maps can be associated with certain forms of stacking faults, which enables studying such defects in situ and disentangling them from simultaneous changes in crystal size and temperature.

Advancements in macromolecular crystallography, driven by improved sources and cryocooling techniques, have enabled the use of increasingly smaller crystals for structure determination, with microfocus beamlines now widely accessible. Initially developed for challenging samples, these techniques have culminated in advanced beamlines such as VMXm. Here, an in vacuo sample environment improves the signal-to-noise ratio in X-ray diffraction experiments, and thus enables the use of submicrometre crystals. The advancement of techniques such as microcrystal electron diffraction (MicroED) for atomic-level insights into charged states and hydrogen positions, along with room-temperature crystallography to observe physiological states via serial crystallography, has driven a resurgence in the use of microcrystals. Reproducibly preparing small crystals, especially from samples that typically yield larger crystals, requires considerable effort, as no one singular approach guarantees optimal crystals for every technique. This review discusses methods for generating such small crystals, including mechanical crushing and batch crystallization with seeding, and evaluates their compatibility with microcrystal data-collection modalities. Additionally, we examine sample-delivery methods, which are crucial for selecting appropriate crystallization strategies. Establishing reliable protocols for sample preparation and delivery opens new avenues for macromolecular crystallography, particularly in the rapidly progressing field of time-resolved crystallography.