9.2  A test instrument for the component V_sample

This is one of many test instruments written with the purpose of testing the individual components. We have picked this instrument both to present an example test instrument and because it despite its simplicity has produced quite non-trivial results.

The instrument, Tests_samples/Samples_vanadium, consists of a narrow source, a 60’ collimator, a V-sample shaped as a hollow cylinder with height 15 mm, inner diameter 16 mm, and outer diameter 24 mm at a distance of 1 m from the source. The sample is in turn surrounded by an unphysical \(4\pi \)-PSD monitor with \(50 \times 100\) pixels and a radius of \(10^{6}\) m. The set-up is shown in figure 9.1.

9.2.1  Scattering from the V-sample test instrument

In figure 9.2, we present the radial distribution of the scattering from an evenly illuminated V-sample, as seen by a spherical PSD. It is interesting to note that the variation in the scattering intensity is as large as 10%. This is an effect of anisotropic attenuation of the beam in the cylindrical sample.