Conference Agenda

A proposal for a high brilliance upgrade to the SOLEIL synchrotron radiation source is expected to increase the beam brightness by > 50 times on beamlines used for life sciences. The combined expertise of the life sciences beamline teams at SOLEIL form the HelioBiology section, which has been, for the last 4 years, developing a post-upgrade approach to structural biology. This approach will be presented, paying particular attention to facilities that are novel to SOLEIL including in-vivo crystallisation [1] , microfluidic devices and their synchrotron applications [2], and concrete efforts towards an integrated approach to structural problems. Initial proposals for structural biology facilities (including an on- and off- beamline portfolio of instruments) will be presented, drawing on recent examples to illustrate the approach.

This work is presented on behalf of the members of the HelioBio scientific section at SOLEIL (https://www.synchrotron-soleil.fr/en/research/house-research/biology-health-heliobio).

References

[1]. Banerjee, S., Montaville, P., Chavas, L.M.G., Ramaswamy, S. "The New Era of Microcrystallography" Journal of the Indian Institute of Science., 98(3): 273–281. (2018).

[2]. Chaussavoine, I., Beauvois, A., Mateo, T., Vasireddi, R., Douri, N., Priam, J., Liatimi, Y., Lefrançois, S., Tabuteau, H., Davranche, M., Vantelon, D., Bizien, T., Chavas, L.M.G., Lassalle-Kaiser, B. "The microfluidic laboratory at Synchrotron SOLEIL" Journal of Synchrotron Radiation., 27(1): 230-237. (2020).

The global need to collect diffraction data from micro-crystals has been reflected by the development of dedicated microfocus beamlines for macromolecular crystallography worldwide. The increased intensity and brightness of these beamlines imposes a fundamental limitation however which precludes successful structure determination from a single microcrystal: radiation induced damage. X-ray induced radiation damage means that data must often be merged from many crystals to yield a complete dataset for structure solution [1, 2]. This is frequently the case for challenging projects when only crystals of limited size are available. Increasing the X-ray energy beyond the typical 10-15 keV range promises to provide a solution to this problem via an increase in the amount of information that can be obtained per unit absorbed dose or ‘diffraction efficiency’ [3-5].

To date however hardware limitations have negated any possible high energy gains. Typically the sensor material of detectors used in macromolecular crystallography is silicon. With its low atomic number, silicon becomes transparent as the X-ray energy is increased and the detector quantum efficiency falls rapidly as a function of energy. Recently, detectors using cadmium telluride as a sensor material have been developed; resulting in a quantum efficiency of 90% below the cadmium absorption edge (26.7 keV) and nearly 80% up to energies of 80 keV [6].

Through use of a new cryogenic permanent magnet undulator and a Cadmium Telluride Eiger2 detector high photon fluxes at high energies (>20 keV) can be generated and resulting microcrystal diffraction efficiently detected. Our results show that at higher energies fewer crystals will be required to obtain complete data, as the diffracted intensity per unit dose increases significantly between 12.4 and 25 keV. In an additional gain for the crystallographer, we observe that data collected at higher energies typically extend to higher resolution. Taken together our results illustrate that the use of high energies allows the best possible data to be collected from small protein crystals pointing to a high energy future for synchrotron-based macromolecular crystallography.

During the last decades, structural biology had a major impact in understanding the structure-functional aspects of some of the most important biological machineries. The new ESRF Extremely Brilliant Source opened a new age in microcrystallography and permitted to extend further the capabilities of the macromolecular crystallography beamlines and will open new pathways in the study of time-dependent structural changes. This is the scope of the upgrade of the ID29 beamline.

The new beamline combined cutting edge instrumentations to fully exploit serial crystallography experiments at room temperature. This presentaition will present the the beamline design with particular relevance to the new instrumentations and present the new scientifc opportunities that it will offer to the structural biology user community.

To study the effect of high pressure on any sample property, suitable pressure devices are a fundamental requirement. Their design has to be tailored to the experimental demands regarding the intended pressure, the employed instrumentation and the expected scientific results. Our work presents the development of high pressure cells for neutron scattering on polycrystalline and single-crystalline samples at low temperatures and with applied magnetic fields.

One of the most common devices for high-pressure neutron experiments is the clamp cell [1], where the pressure is applied ex situ and which can be used independently in various setups. Our cell design [2] has been specifically developed for neutron scattering experiments at low temperatures in the closed-cycle cryostats on the instruments DNS (diffuse scattering neutron spectrometer), MIRA (cold three axes spectrometer), and POLI (polarized hot neutron diffractometer) at the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching, Germany. Two variants of the compact monobloc cell (Fig. 1) were produced, one from CuBe alloy and from NiCrAl “Russian Alloy”, working up to about 1.1 GPa and 1.5 GPa, respectively. The low paramagnetic moment of both alloys allows also measurements of magnetic properties.

First tests of the cell with neutron radiation were performed to calibrate the load/pressure-curve of the CuBe cell (up to 1.15 GPa) (at POLI), to estimate its neutron absorption and background (at MIRA), and to measure magnetic reflections (at MIRA). In addition, the thermal response in the cryostat of DNS was measured, and the experimental findings were complemented by simulations.

Ultimately, these cells are intended as standard cells for high pressure measurements on different instruments at MLZ suitable for all available magnets and cryostats down to 1.5 K. Further tests under various conditions (temperature, pressure, magnetic field) as well as simulations are planned for both cells in the near future. The results will help both to establish the present cells and to optimise the design of subsequent cells to achieve higher pressures, to fit into smaller cryostats and to enable neutron-independent pressure calibration.

Figure 1. Schematic drawing of the clamp cell.

[1] Klotz, S. (2013). Techniques in High Pressure Neutron Scattering. CRC Press.

[2] Eich, A., Hölzle, M., Su, Y., Hutanu, V., Georgii, R., Beddrich, L. & Grzechnik, A. (2020). High Press. Res. 41[1], 88–96.

High-end x-ray scattering techniques such as BIO-SAXS (e.g. SEC-SAXS), non-ambient SAXS and GISAXS rely heavily on the x-ray source brightness for resolution and exposure time. Traditional solid or rotating anode x-ray tubes are typically limited in brightness by when the e-beam power density melts the anode. The liquid-metal-jet technology has overcome this limitation by using an anode that is already in the molten state.

We have previously demonstrated prototype performance of a metal-jet anode x-ray source concept with unprecedented brightness in the range of one order of magnitude above current state-of-the art sources. Over the last years, the liquid-metal-jet technology has developed from prototypes into fully operational and stable X-ray tubes running in many labs over the world. Small angle scattering has been identified as a key application for this x-ray tube technology, since this application benefits greatly from high-brightness and small spot-sizes, to achieve a high flux x-ray beam with low divergence. Multiple users and system manufacturers have since installed the metal-jet anode x-ray source into their SAXS set-ups with successful results. With the high brightness from the liquid-metal-jet x-ray source, time resolved and in-situ SAXS studies can be performed – even in the home laboratory.

This presentation will review the current status of the metal-jet technology specifically in terms of flux and brightness and the impact of SAXS measurement. Such as the influence of the size of the x-ray source and its distance to the x-ray optics on the divergence will be discussed, and how to minimize the divergence and maximize the flux in SAXS experiments targeted to specific applications. It will furthermore refer to some recent SAXS and GISAXS data from users of metal-jet x-ray tubes.

For the first time, holistically optimized laboratory x-ray absorption spectroscopy (XAS) systems enable XAS measurements of most elements in the periodic table (Z>13) in minutes with energy resolution better than 0.7 eV, approaching capabilities of XAS facilities using bending magnet beamlines at second generation synchrotron light sources. The optimizations include:

• High brightness x-ray source with high thermal conductivity target incorporating diamond substrate, multiple target materials providing smooth spectrum free from characteristic x-ray lines, x-ray source size and shape optimized for using low miller index diffraction planes of cylindrically bent Johannsson crystal analyzers at low-medium Bragg angles, which provides optimal tradeoff between x-ray energy resolution and flux.
• Making use of dispersion of cylindrically bent Johannsson crystal analyzers in both tangential and sagittal directions for efficient use of source x-rays.
• 2D photon counting detector for recording x-rays dispersed by the crystal analyzer in tangential and sagittal directions and rejecting harmonics reflected by a crystal analyzer.

With those options, we have developed laboratory XAS systems operating from 1.7 keV to 25 keV, providing monochromatic x-ray flux over 2*10^7/s, and achieved energy resolution better than 0.7eV. The design and performances of the systems will be presented.