Welcome to I20-Scanning

The high flux and high spectral purity are the key design parameters of this beamline. The beamline is equipped with an in-house designed four-bounce monochromator which consists of two pairs of counter-rotating crystals. The advantages are: a) high stability and reproducibility, b) fixed exit by geometry, c) energy resolution of transmitted photons not determined by the incident beam divergence and, d) reduction of the tails in the reflectivity curves.

The determination of the local structure around a photoabsorbing atomic site present at low concentration (about 1.0 mM) and/or in X-ray unfavourable heavy matrix is one of the particular strengths of I20-scanning when operating in the conventional scanning XAS mode. 

X-ray emission spectroscopy (XES) provides sensitivity to the valence state and the nature of the bound ligands.

The monochromator in the Precision Metrology Lab (PML) for commissioning and alignment 

The new monochromator is scheduled to be installed in the summer of 2026 after AP39. The installation phase is expected to last a couple of months and will be followed by X-ray commissioning. The beamline is anticipated to be operational starting in February 2027, with the new monochromator extending the energy range to the original specification of 34 keV. The Si(111) crystals will cover the range of 4 to 20 keV, while the Si(311) crystals will cover the range of 7 to 34 keV. 

A 'Conti' side-loading cryostat will be available from AP37. This cryostat can be used with both LN2 and LHe and is compatible with the XES end station.

A Micro-tomo furnace is currently under commissioning and will be available from AP38. 

The new fourteen analyser spectrometer is now in regular use.  It can be used with 14 crystals of the same type or two sets of seven depending on the experimental requirements, however  because of the time it takes to change and align crystals, the analyser crystals cannot be changed during a visit. Often an extra day will be scheduled to set up the analyser.before your visit, which is shown as scheduled beamtime but used by the beamline team to prepare the analyser for your experiment and so you are not expected to attend on this day.

Status Update April 2023

After delays caused by the pandemic and then the priority changing to install the new XES Spectrometer, the new 4 bounce monochromator project has kicked off. It is hoped a new monochromator that will reach ca 30 keV will be installed on the beamline in late 2024 or early 2025.

Status Update March 2019

The previous incarnation of the four bounce monchromator has been in regular user use for the last two years. The Si(III) set of crystals work well with some minor issues. The monochromator takes some time to thermally equilabrate when changing edge thus the beamline was normally only used for one edge per experimental user session apart from adjacent edges.  The monochromator is very vibration sensitive and hence the area around the I20 optics hutch is barriered off to prevent external stimuli to activate these modes.

A new first axis is being installed, after extensive testing, in March 2019 with an enlarged second crystal ,. This should reach thermal equilibrium much faster and so make edge changing faster if not routine. It will not be a user -enabled process like B18, but it may be possible to look at more than one edge in an experimental visit. The new axis will be commissioned in April 2019, so more will be known then.

The new axis does not have room for a 311 crystal set and thus routine high energy use will not be available for some time. It is possible that the Si(333) will provide high energy X-rays but this remained to be proven. Hence the beamline energy range is likely to stay at 5-20 keV until a new monochromator is installed. 

The 64 element has had Xspress4 electronics fitted this year which has improved its performance radically making it simpler to collect data on samples with high scattter or other elements in high concentrations.