26 November 2014
I20-1 is now I20-scanning
I20-2 is now I20-EDE
Please reference the beamline and the branchlines with these new names in your publications.
The determination of the local structure around a photoabsorbing atomic site present at low concentration 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. 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 main advantages are: a) high stability and reproducibility, b) fixed exit by geometry, and c) angle and energy resolution of transmitted photons are not determined by the incident beam divergence.
|Energy range|| |
Si(111): 4 - 20 keV
Si (311)+: 7 - 34 keV
|Energy resolution|| |
Si (311)+: ΔE/E=2.8x10-5
|Flux at 10 keV (ph/s)||> 1012|
|Beam size at sample (µm)|| |
HxV = 400 x 300
+not available at current time
Status Update April 2016
Towards the end of last year we assessed the performance of the beamline after the implementation of the changes in the control system of the four bounce monochromator. The success of these tests allowed us to take the decision to retain the four bounce configuration on the beamline and restart a user programme, albeit with a limited energy range: from 6keV to 20keV. Since then we have been working through the backlog of proposals that were already awarded beamtime.
To date several experiments using the emission spectrometer have been performed in the beamline and others are scheduled to take place before the end of the current run. The following run will be devoted to performing outstanding experiments that require use of the multi-element fluorescence detector. From October the backlog of experiments on the beamline should have been cleared and we will be performing the experiments received in the last call, April 2016.
Whilst these experimental activities have been underway we have continued to work on improving the cooling of the first crystal of the monochromator. To avoid any risk of jeopardizing the current performance of the beamline, all potential modifications are being extensively tested on the test beamline (B16) under conditions that are as close as possible to I20. We are planning to test the latest design in June and if the results are satisfactory, we should then be able to install this improved system in the four bounce monochromator during the August shutdown.
Performing experiments both in XAS and XES end-stations.
I20-scanning operational in the energy range from 6keV to 20keV.
On-going commissioning of the upgraded monochromator with X-rays.
Implementing changes to the control system of the second axis of the monochromator.
Tests have shown a significant improvement in the overall performance of the system.
New encoders & drive controller implemented in the first axis of the monochromator.
New drive controller and amplifier tested successfully in the prototype axis.
New encoder technology tested in the prototype axis.
Good progress has been made with the control system of the monochromator.
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