Author Archives: Brian

Fancy background subtraction: a second look.

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 […]

Share

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 […]

Share

Introspection

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 […]

Share

Does it matter part 4.2: The actual flatfield

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 one?

Share

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

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 […]

Share

Fancy background subtraction: an initial look

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 […]

Share

Cutting-room clippings

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 Subtraction

Share

Data correction and reduction code functional

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 […]

Share

Speaking of errors: estimating uncertainties in integrated data (corrigendum to “Everything SAXS”)

I feel I need to make a public apology: it turns out that I have been inaccurate in some of my recent papers on the explanation of the estimation of the uncertainties on the intensities (the uncertainties themselves, however, are correct, so I calculated it right but described it wrong). Here’s what happened:

Share

Trouble in Paradise? Internal diffraction in PILATUS-like detectors

A great many of the data correction issues in small-angle scattering can be resolved by trading a kidney for a PILATUS detector [1] (or similar [2]). These are detectors using a single crystal sensor as detection surface, and have extremely low noise, low distortion, high dynamic range and single photon sensing capabilities. However, as investigated […]

Share