Simulation Project tripleaxis: Analyzer and detector

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The second axis in a triple axis spectrometer is the sample, from where the neutrons are scattered in an angle, we here denote TT. Use first a radius 10 mm / inner radius 6 mm hollow vanadium sample (V_sample) and focus the outgoing scattering (in the simulations) on the analyzer below.

To form the third axis in the RITA-2 spectrometer, a PG analyzer crystal is placed 1.26 m from the sample. The size of the analyzer crystal is 0.150 m high and 0.025 m wide. Use the monochromator_flat component with the same parameters as for the monochromator.

The neutrons are scattered from the analyzer into the detector, which is a PSD detector, 0.30 m wide and 0.50 m high, \(128 \times 128\) pixels, placed 0.350 m from the analyzer. Usually, only the middle 19 mm of the detector is used.

Position the analyzer-detector to perform Bragg scattering for 5.0 meV neutrons. The scattering angle at the analyzer is denoted TTA. Confirm that neutrons reach the detector and that it is reasonable to use only 19 mm detector width. Estimate the effective detector height and use this value from here on.

McStas hint

You may like to test the set-up by inserting a \(4\pi\) monitor, centered at the vanadium sample.

Experimental note:

At the RITA-2 instrument, several analyzer blades are used. We will, however, not go into details with that here.