Master's Defense: Kristine Marie Løfgren Krighaar

A Digital Twin of the BIFROST Neutron Spectrometer at ESS

This thesis develops a digital twin of the BIFROST spectrometer at the European Spallation Source (ESS). This twin is created by McStas, aiming to predict energy resolution and simulate dispersion modes. Two models are constructed: the first predicts energy resolution for different analysers and at different h ̄ ω and chopper openings from 0.1 to 1 ms, showing a range of 15-60 μeV FWHM on the elastic line and a maximum of 1.6 meV at energy transfers as high as h ̄ ω 50 meV. The second, a more comprehensive model, which also is able to map the q-dependency, accurately simulates dispersion modes from a Pb phonon, validating with a sound velocity with a precision of 0.6%. These results demonstrate the utility of the digital twin in predicting instrument performance and simulating complex scattering phenomena, offering valuable insights for future development of the BIFROST spectrometer.


Passcode: 998184