Hard X-ray synchrotron biogeochemistry: piecing together the increasingly detailed puzzle

Abstract

Synchrotron techniques have increasingly been used to explore complex biogeochemical 11 processes over the last two decades [1]. In this relatively short period of time the advances in 12 optics, detector systems and ultimately beamline performance and capabilities have been 13 staggering. While a very large number of synchrotron methods are available and are 14 employed in biogeochemistry, this perspective article will mainly explore recent 15 developments and trajectories for ‘hard’ X-ray techniques. State-of-the-art beamlines, such as 16 the nano-imaging and nano-analysis (NINA) end-stations at the European Synchrotron 17 Radiation Facility [2], will increasingly provide users with unprecedented analytical 18 capabilities. For instance, the NINA end-stations will provide nanoscale resolution (10-20nm 19 for imaging and 50-100nm for XAS and XRD) together with high photon fluxes, a wide 20 energy range and sophisticated sample environments. It is pertinent to note that the scientific 21 case for the development of this project specifically mentions environmental and earth 22 science as one of the three main drivers [3]. To take full advantage of this increase in lateral 23 resolution two further areas also need to simultaneously develop: sample preparation / 24 preservation and detector technologies. The need for fast detection is dictated by both the 25 necessity to representatively explore the heterogeneity of environmental samples and to 26 minimise the risk of beam damage. In the last few years, the advent of a new generation of 27 fast fluorescence detectors has gone a long way toward meeting this need (e.g. [4]). Similarly, 28 an increasing number of beamlines are developing cryo-compatible platforms to reduce 29 radiation damage and allow hydrated samples to be investigated in a frozen state.