Engineering and Environment Village

Major developmental highlights at the Engineering and Environment village this year relate to the opening of the Long Duration Experimental (LDE) facility at I11 and the optimisation of the new X-ray Pair Distribution-Function (XPDF) beamline I15-1. The village also continues to improve and add to its offering of sample environments and this work will carry on into the next year. While the common software analysis suite deployed throughout the village is currently at a high level of maturity and used by most users, it is also being continually improved in order to provide a better and more versatile user experience.

The LDE facility in the second experimental hutch on the Powder Diffraction beamline (I11) is the world’s first synchrotron long duration experiment instrument. It is currently hosting six experiments. In 2015 significant effort has been put into developing a range of sample environments for the facility, giving users the chance to run a wide array of experiments that simulate long term behaviour as it occurs in natural states or processing conditions.

An automated environmental cold cell at the facility now lets users cool the sample environment by 1 °C a day down to a minimum of -30 °C. This environment is currently employed to mimic the effect of Arctic winter in order to study mineral formation in sea ice. An electric battery charger is also available and can be used to simulate the life cycle of new generation batteries over time. The sample environment is able to hold up to six batteries, which can each be charged and discharged in an hour. More in operando experiments are planned for next year. Humidity chambers – including a dry cell of around 15% humidity and a wet cell of up to 65% humidity for pharmaceutical research – are currently available. The coming year will see the commissioning of the LDE facility as it is fine-tuned, as well as the development of more sample environments, e.g. large volume cells (up to 50 bar and 400 °C).

 
Figure 1: Support Scientist, Claire Murray, with I11’s long duration experimental facility.

Plans are in place to install a Dynaflow He cryostat and a low pressure gas spinner in the first experimental hutch at I11 within the next six months. With the low temperature device available, users will be able to change the temperature at the beamline down to 4K. It is hoped that this will be particularly useful for users wishing to study phase transitions, especially magnetic solids whose properties can change at very low temperatures. The new gas spinner will enhance the existing gas cells by improving the data quality from in situ adsorption experiments.

The main development at the Extreme Conditions beamline (I15) has been the integration of the control and vacuum infrastructure of the new beamline I15-1 into the existing controls architecture. I15-1 will take on all the XPDF studies currently taking place at I15. The new beamline shares the same source as I15 but all X-ray components are separate and can be operated completely independently from a separate control cabin. The end station for I15-1 is now complete. First light and first users were achieved in April 2016. I15-1 also has its own team, including two staff scientists, technician and post-doctoral research assistant.

Having a beamline dedicated to XPDF studies will allow it to be optimised for pair distribution function measurements, ultimately providing data collection and analysis software to allow non-expert users to use this technique. Day one sample environments consist of a flexible sample stage for capillaryand plate-geometry samples to be measured at temperatures from about 100 K to 1000 °C.

Figure 2: The I15-1 beamline team.

At the main I15 beamline, progress has been made with the diamond anvil cell (DAC) laser heating system. DAC laser heating is an important experimental technique in extreme conditions science as it is the only way to study samples under extreme pressure (100s of GPa) and temperature (1000s of K). Combining DAC laser heating with in situ synchrotron X-ray diffraction allows samples to be characterised structurally while being subjected to these extreme conditions.

Throughout 2015 off- and on-line DAC laser heating systems have been developed and commissioned. In early 2015 the off-line laser heating system was used for the first time by users. These experiments investigated the formation of alkali metal hydrides under combined conditions of high pressure and temperature. The installation of the online laser heating setup was successfully commissioned in December 2015, immediately followed by the first user experiment. Here mineral samples were compressed to high pressure and then laser heated while in situ diffraction patterns were recorded. In this setup the laser paths are integrated into the micro-focussing station (X-ray beam size about 10 μm) for in situ powder diffraction measurements. The temperature is extracted from the thermal emission spectra from the sample recorded during the diffraction experiment. These temperature data are automatically saved together with the 2D-diffraction pattern. The laser heating system is now available for the user community. 

Figure 3: JEEP’s (I12) internal experimental hutch.

The open architecture of I12 and its provision of high-energy X-rays allow users to develop and apply new methods of in situ processing experiments. The I12 team has worked with a research team from the Institute of Shock Physics at Imperial College, London, on high-speed imaging with nanosecond time resolution. This has been made possible by synchronising the bunch pattern of the electrons in the storage ring. Following this, the beamline successfully carried out studies in ultra-fast deformation and propagation of shock waves through material¹.

Tomography users benefit from the adaptability of the I12 instrument in that they can insert custom-made apparatus to perform complex sample manipulation during the tomography scan. Fast high-resolution tomography leads to new insights into the convoluted processes during material processing close to industrial application, such as the liquation induced cracking of grains during deformation². The biomedical community can benefit from the large, high-energy beam on I12. It enables body parts to be studied in their completeness avoiding destructive sectioning, for example in the investigation of the biomechanics in the eye under increased intraocular pressure³. The tomography instrument is therefore continuously undergoing upgrades to enable an efficient integration between the fast I12 X-ray camera and data acquisition system and users’ own sample environments that are brought onto the beamline. An important role is the technical advancement of hardware for fast and reliable synchronisation of user-equipment and detectors⁴. At the same time the improvement in optical designs for robust and efficient recording of high-resolution X-ray images go hand in hand with improved artefact corrections provided by the beamline staff, for instance the removal of often overlooked occurrence of optical distortions⁵. Detection of systematic disturbances in the recoding of images such as local non-linear sensor response or micro-heterogeneities in scintillators dramatically improve the visibility of very low contrast objects with strong attenuation, which are typical in a paleontologist’s research for the non-destructive rendering of fossils included in minerals⁶.

The I12 diffraction instrument is used almost exclusively for time-resolved experiments. As in tomography, the integration and synchronisation of userequipment with the diffraction system is crucial to the experimental success. This is the case in chemical processing for the study of reaction kinetics⁷ as well as in material science, for instance, to look at electrically induced strains in functional ceramics⁸.

References:

1. Eakins D. and Chapman D. Review of Scientific Instruments 85, 123708 (2014).
2. Karagadde S., Lee P., Cai B. et al. Nature Communications 6, 8300 (2015).
3. Coudrillier B., Geraldes D., Vo N.T. et al. IEEE Transactions On Medical Imaging (2015).
4. Cobb T., Chernousko Y. and Uzun I. Proceedings of ICALEPCS2013 (2013).
5. Vo N.T., Atwood R.C. and Drakopoulos M. Optics Express 23 (25), 32859- 32868 (2015).
6. Garwood R. J., Dunlop J. A., Selden P.A. et al. Proc. R. Soc. B 20160125 (2016).
7. Wu Y., Breeze M., Clarkson G., et al. Angewandte Chemie 128 (2016).
8. Khansur N. H., Rojac T., Damjanovic D. et al. Journal of The American Ceramic Society (2015).

I11, the Powder Diffraction beamline, supports a wide range of science including material chemistry, environmental research and investigations into new materials used for energy storage and other applications. The beamline offers high resolution and time-resolved powder diffraction studies to its users through two end stations, allowing investigation into a sample’s structural properties and behaviour.

I11’s first end station runs studies that offer temporal resolution on a subsecond to minute timescale. Thanks to a range of temperatures covering 4 K to 1500 °C, the facility is suitable for users who want to study materials as they are used in situ. Other sample environments include humidity chambers as well as high and low pressure gas cells suitable for a range of gaseous environments (e.g. carbon dioxide, ammonia, methane, hydrogen). This year has seen the beamline support research into new lithium-ion battery materials as well as nanoporous molecular frameworks for greenhouse gas capture and catalysis.

The second end station at I11 is now fully open to users. This end station is designed for Long Duration Experiments (LDE) and has the capacity to host 20 experiments in tandem. Six experiments are currently running and up to a further four will be phased onto the beamline over the next nine months. Experiments, which last for a minimum of two weeks and up to a maximum of two years, are run continuously with data being collected on a weekly basis. Users can also have the opportunity to extend their experiment at the end of the proposed duration if necessary. A wide variety of sample environments allows the LDE facility at I11 to host a diverse range of science. Research supported during 2015 includes the degradation of lithiumion batteries, the effect of humidity on pharmaceuticals, and geochemical processing in cold aqueous environments.

I12, the Joint Engineering, Environmental and Processing (JEEP) beamline, offers environments that allow users to study scientific problems that are very close to real-world applications. It is the only beamline to use very high energy X-rays (between 50 keV to 150 keV), giving I12 the unique ability to penetrate through samples of significant thickness. Thanks to this, users do not need to prepare subsets of samples for the beamline but can investigate the sample in question without destruction. The beamline’s design also enables users to use their own sample environments, such as chemical or material processing environments, opening up the possibility for investigation without having to scale down processes.

I12 offers users several techniques on both the imaging and X-ray diffraction sides. 2D imaging and tomography are available, while diffraction studies include monochromatic X-ray diffraction, white light (also known as polychromatic) X-ray diffraction and Small-Angle Scattering (SAS), the latter of which gives users the ability to study structural clusters that range from from 10 to 100 nm in size. This year has again seen I12 host a diversity of studies across material science, engineering, chemical processing and to a lesser extent biomedical research and paleontology. Significant effort has been put into increasing the in situ processing speed. Last year upgraded mechanics and more efficient cameras allowed tomography sets to be acquired at a rate of at 20 Hz. This year a user group has used single bunch imaging on the beamline to take images in as short a time as 10 ns, allowing them to take snapshots of fast material deformation.

The Extreme Conditions beamline, I15, like I12 also uses high energy X-rays, in this case ranging from 20 to 80 keV. However, I15 is set up to support investigations carried out at extreme conditions, specifically at high pressure and/ or temperature. The beamline can support experiments at pressures of up to several megabars and thousands of degrees in temperature, simulating the conditions found deep inside the earth. Over the last year a diamond anvil cell laser heating system has been incorporated on the second experimental station at the beamline. A major development for I15 this year has been the construction of a second beamline, I15-1, which has been built without compromising the user operation on I15.

I15 supports powder and single crystal diffraction techniques alongside X-ray Pair Distribution-Function (XPDF) studies. To date all techniques have been hosted at the same end station but from April 2016 XPDF measurements were moved onto I15-1. This new beamline will share the same source as its parent beamline but has its own dedicated X-ray optics and beam conditioning components in a new experimental hutch to optimise the quality of the XPDF data. As with the other beamlines in the village, the user community at I15 is widespread, including researchers from solid state physics, solid state chemistry, materials science, engineering and the life sciences.