Articles by Brian

New theme

2015/04/19 // 1 Comment

Dear readers. I felt the old theme, “Redline”, had not seen an update in too long a time. After searching for a while I found this new theme. Let me know if you like it or not; changing back is always an option. The header image still needs to be changed, and I hope that with later posts the post images will be scaled better to the post. If anyone can recommend a better theme, please let me [...]

Fancy background subtraction: a second look.

2014/07/14 // 0 Comments

During last week’s visit to BAM in Berlin, I and Ingo played around with some equations. In particular, we were curious if we need to do something special to get the scattering from a sample in a capillary, i.e. a sample between an upstream and a downstream sample cell wall. Long story short: we arrive at a rather ordinary equation after a lengthy [...]

On tour

2014/05/12 // 0 Comments

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 [...]

Introspection

2014/03/31 // 0 Comments

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 [...]

Does it matter part 4.2: The actual flatfield

2014/03/24 // 0 Comments

Last week, I talked about how to determine whether a flatfield correction was necessary. Data from a Bruker Hi-Star detector was shown to have very large local sensitivity deviations in the 2D detector image (of +/- 50%), and would therefore need a flatfield correction. So how to get [...]

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

2014/03/17 // 2 Comments

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 [...]

Fancy background subtraction: an initial look

2014/03/10 // 1 Comment

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 [...]

Cutting-room clippings

2014/03/03 // 0 Comments

For today’s post, I had a few things planned, but haven’t been able to work anything out yet. So I’ll talk a little about these bits and pieces: Upcoming conferences and meetings, some future instrumentation plans, and a little about the Fancy Background [...]

Data correction and reduction code functional

2014/02/24 // 0 Comments

Before I get started, let me just highlight the new small-angle scattering issue of J. Appl. Cryst. which has come out a few days ago. My contribution was unfortunately not accepted (and I haven’t worked much on it since due to rejection depression), but the journal is still very much worth a read! Now for the main topic of today’s post. Regular readers will know that I have started implementing the “Everything SAXS”-set of data corrections in the Python language. Having worked on it in between other tasks (evident from the commits to the repository), it is now in such a state that it can do enough to do basic correction and reductions, with uncertainty propagation. At the moment, it is not very user-friendly (no GUI, for example), but it is modular and flexible, with an easy syntax. The correction modules are straightforward and easy to read and write, and Pythonistas will be able to dig right in and use it to do the necessary corrections. Here’s the [...]
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