Category Archives: Looking into something

Intensity in density

A few weeks ago, a dataset landed on my desk from a very dense system: scattering from dry, packed SiO2 nanoparticle powder. Dense systems add a degree of complexity to small-angle scattering, so it was interesting to try (play) and find a solution to this.

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12 corrections in a row

Just a couple of housekeeping notes: I’m giving talks in Europe in a month at the following locations: Unité Matériaux et Transformations (UMET), Lille on May 16, hosted by Grégory Stoclet, Birmingham University, Birmingham on the 20th of May, hosted by Zoe Schnepp, Nottingham University, Nottingham, on the 23rd of May, hosted by Philip Moriarty, […]

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How to fit a scattering pattern part 1: the initial look.

By the way, my topical review paper on SAXS data collection and correction has been published and is available open access here!   Recently, some good colleagues (who are not familiar with scattering) have started asking questions on how to go about fitting a scattering pattern. This was a very good opportunity to think about […]

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Comment on the current state of internet surveillance

Unfortunately, not everything can be solved with small-angle scattering. Current affairs have led me to write this post, in which I try to highlight the magnitude of the surveillance situation in a few paragraphs. If you are not interested in political commentary, please be so kind as to skip this post and wait for the […]

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NIM-duino as ersatz counter-ratemeter (counts up to ~50000 counts per second)

The Bonse Hart USAXS instrument is coming along nicely, and the expectation is that we can start using X-rays pretty soon. One missing element in my detector electronics chain, however, is a counter and rate-meter. Normally, one would buy these as NIM modules, in which case they are very nice, reliable and expensive (for example […]

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Does it matter? part 3: Natural background radiation

[With thanks to dr. Masato Ohnuma for bringing this to my attention] It is all around us, and occasionally all through us, and every now and then, your small-angle scattering detector might see them: photons from nature. Do we need to consider these all-natural organic photons in the data corrections we do, or can we safely […]

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Ruler vs. Silver behenate: Trust but verify

One of the most important parameters you need when analyzing small-angle scattering patterns is the distance from the sample to the detector, as this defines the scattering wave vector q. This is often determined using the same approach as for wide-angle diffraction: measurement of a standard crystalline sample. Whereas in the past, stretched rat tail […]

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Movie: Monte-carlo fitting of anisotropic scattering

I have worked on monte-carlo procedures for a while now. Initially (while working for Aarhus University), I managed to make these work to extract the particle size distribution from isotropic scattering patterns, and it works fine and quick. Now though, I managed to get this trial-and-error procedure to work for whole 2D pattens as well! […]

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Nothing new here

So it seems science has beaten us to the punch once again. Remember last week’s optimistic story on how you can make better use of your (measurement) time? Turns out it has been done (at least once) before. The year was 1993, the authors were M. Steinhart and J. Pleštil, and they did the same […]

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Making better use of your time: optimizing measurement time

Often, especially when measuring on big facilities, you are given a limited amount of time. So when it comes to measuring the sample and the background, this limited time has to be divided between a measurement of the sample, and a measurement of the background. Normally, one would spend about 50% of the time on […]

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