Karl-Erik Larsson died on January 24, 2015 after a short period of illness. He initiated neutron scattering research in Sweden in late 1950's after having learned this experimental technique during a stay at Brookhaven National Laboratory. He was at this time employed by the Swedish Atomic Energy Company and became 1963 professor in Reactor Physics at the Royal Institute of Technology in Stockholm. During the sixties and the seventies he was several times assigned by the International Atomic Energy Agency to join conferences in the developing part of the world to promote the construction of small research reactors and the use of neutrons in fundamental and applied sciences.
This resulted in a flow of scientists coming to Stockholm for training in the neutron scattering together with the many young Swedish members of his department. By these activities he put the Swedish neutron scattering community on the international map. After being one of the first who at the same time as Brockhouse measured the dispersion curves in aluminium his interest turned to studies of atomic motions in liquids, both metallic and organic. His work on liquid helium during the late fifties in which he together with Palevsky and Otnes confirmed some predictions of Landau concerning excitations in liquid helium was quickly recognized internationally. Karl-Erik was furthermore a dedicated teacher and his courses attracted many students.
Besides his research he and his wife spent lots of their free time walking and paddling in the Swedish countryside. Being from his young years a very able cross-country ski-runner Karl-Erik finished the yearly Vasa race—a ski run over 90 kilometres—no less than forty times.