Fundamental Research

Neutrons unravel 50-year-old physics mystery

More than 50 years ago, researchers discovered a pronounced phase transition in strontium iron oxide at room temperature. However, what exactly happens in this process at the atomic level has been unclear ever since. Using high-resolution neutron measurements, a research team from the Max Planck Institute for Solid State Research at the Heinz Maier-Leibnitz Center (MLZ) has now been able to solve this old mystery.

Monte-Carlo calculated detector response functions to unfold radiative neutron capture spectra

A complete set of detector response functions, i.e. the gamma spectra corresponding to incremental gamma-ray energies up to 12 MeV, were obtained for the Budapest PGAA facility by geant4 Monte-Carlo simulations and were used to unfold the experimental prompt-gamma spectra, for use in nuclear physics.

The unfolding successfully removed the continuous Compton-background and the escape peaks related to a full-energy peak but preserved the shape and area of the full-energy peak itself.

Structuring of nanoparticle suspension probed by neutron reflectivity

The behaviour of colloidal particles at water-solid interfaces is relevant in material science, food processing, medicine and environmental engineering. A team from the University of Geneva with researchers from the Budapest Neutron Centre used neutron reflectivity to study colloidal silica nanoparticle suspensions near the (negatively) like-charged native-oxide-covered surface of Si. Intriguingly, the nanospheres develop a self-organised damped, oscillatory concentration profile normal to the interface, as demonstrated in the figure.