On tour

Dear reader,

In a few moments, I will be boarding the flight to Europe for the whirlwind SAXS tour and diamond experiments. I will post during and about the trip, so posts should appear with irregular timing on this site, so check frequently!

feel free to stop me for a coffee as well!

regular programming will resume in two weeks.


The making of… a SAXS presentation


Over the last few weeks, I have been working mostly on preparing presentations. It’s not just for the upcoming fun European Tour, but I also gave a 30-minute presentation for a selection committee. This is a part of the application procedure for a permanent position here (though the application process won’t be finished for a while yet), so it was kind of important to get it right.

To shed some light on how to go about preparing one of these presentations, I thought I would deviate this week from the normal SAXSy topics to explain the process I go through when setting the application talk. Read more »


Guest Post by Dr. Grégory Stoclet: Crazy deformation of polymers, studied with in-situ SAXS.

[ED: I've started asking around for guest contributions for the LookingAtNothing site, in order to provide a broader view of the SAS-related activities that I could ever hope to achieve by myself. Our first guest to talk about his work is Dr. Grégory Stoclet of UMET at the Université Lille 1.]

PLA is a new biodegradable polymer used for in many applications such as disposable packaging as medical implants. While it behaves like a brittle material at room temperature, it quickly becomes ductile by raising the temperature a few degrees. To understand why this happens, we are studying the plastic deformation mechanisms using SAXS. Read more »


12 corrections in a row

Close-up of the effect of data correction

Just a couple of housekeeping notes: I’m giving talks in Europe in a month at the following locations:

  1. Unité Matériaux et Transformations (UMET), Lille on May 16, hosted by Grégory Stoclet,
  2. Birmingham University, Birmingham on the 20th of May, hosted by Zoe Schnepp,
  3. Nottingham University, Nottingham, on the 23rd of May, hosted by Philip Moriarty,

Between these dates, I’ll also be joining Zoe and Martin for beamtime at the Diamond synchrotron (beamline I11) between May 21 and May 23. Please feel free to stop me at these locations and say hi!

For today, I’ve got another bit of data correction to show. I thought it might be interesting to put them all together and show you what difference it makes to an integrated scattering pattern. Many of the data corrections implemented are quite straightforward shifts and scalings, but some are more involved and have a greater effect on the scattering pattern. Read more »



Me before starting my Ph. D. project.

I’ve been working on a lot of things of late, but none are yet in a state to show here yet. However, when talking to a colleague last week, I found it hard to explain why I do what I do: why I am so focused on metrology. But maybe I can explain it a little here (warning: rambling ahead! I have been reading books and may come over as slightly lyrical). Read more »


Does it matter part 4: flatfield correction on a Bruker HiStar wire detector

Detector deviation from the azimuthal mean; a first approximation at obtaining a flatfield image. Color scale clipped to -0.5, 0.5 (-50% and 50% deviation, respectively).

See the previous posts in this series here: Part 1, Part 2 and Part 3

Very recently, Bruker upgraded their SAXS instrument in our building. This is a typical 3-pinhole 2D SAXS system that was largely designed by J. S. Pedersen in Aarhus a decade or so ago. This particular version was at NIMS in the Quantum Beam Unit / Neutron Scattering Group, and was using chromium radiation (a very low energy radiation). Now that its source has been upgraded to my favourite molybdenum type (a high energy radiation), it is time to check all of its corrections once more, starting with the flatfield. Read more »


Fancy background subtraction: an initial look

Schematic overview of the considerations of the fancy background subtraction.

As indicated last week, some spare time has been spent trying to re-derive a correction for separating sample container scattering from the sample itself. Normally, a simple background subtraction suffices, but for those who want to go the extra mile (and in particular for those working with strongly absorbing sample containers and samples), you need something a bit more fancy. Read more »