Olav Ullaland, a brilliant detector physicist who spent his career at CERN, passed away on 16 June 2024.
Olav obtained his degree in particle physics at the University of Bergen in 1971. After a short period at Rutherford Appleton Laboratory in the UK, he went to CERN as a fellow in 1973, following which he was awarded a staff contract. He worked as a detector physicist at CERN until he retired in 2009, remaining active for several years as an emeritus. One of his last scientific articles dates from 2020.
Alongside detector R&D, Olav participated in several key CERN experiments. For the Split Field Magnet Detector, located at CERN’s Intersecting Storage Rings, he was in charge of the multi-wire proportional chambers and worked on the prototype of a novel electromagnetic calorimeter that was later adopted by the DELPHI experiment.
After contributing to the UA1 upgrade, he was asked to take a leading role in the complex barrel ring-imaging Cherenkov (RICH) project of DELPHI, which was the first attempt to integrate an imaging Cherenkov detector into a cylindrical collider experiment. The challenges were immense, as it was necessary to operate a gas and liquid radiator, together with a photosensitive gas, at different temperatures in a confined space. Thanks to Olav’s perseverance and the loyalty he inspired in his team, he was able to bring the apparatus to a level where it could be used in physics analysis, for example in the tagging of strange jets from Z and W decays. This was a critical milestone in the history of RICH detectors.
Around 1997 Olav joined LHCb and became a leader in the international effort to make its two RICH detectors a reality. Thanks to his deep knowledge of the many facets of detector physics and techniques, and his ability to remain calm, he and his team managed to find solutions to potential showstoppers. It is testament to Olav’s efforts that the particle identification system of LHCb works so impressively in the study of CP violation and heavy-flavour rare decays. In addition, Olav was the LHCb resource coordinator for several years, taking impeccable control of delicate LHCb financial matters at the beginning of the experiment operations. His expertise in leading many project reviews and trouble-shooting several wide-ranging detector subsystems was also in high demand both within and outside LHCb.
Olav was a wonderful collaborator. He was passionate in his support of students and fellows, and encouraged young people to give presentations and international talks, always graciously stepping away from the limelight himself. His dedication to student training was highlighted by his running of the CERN summer student programme, with both lectures and laboratory courses.
For Olav, work did not finish at CERN, but would be continued in any possible meeting place. These unconventional settings provided a conducive atmosphere to explore, discuss and challenge new projects and ideas, with the goal of promoting cohesion in a critical, constructive and friendly fashion.
Olav Ullaland was not only an outstanding researcher, but also a unique human being who left a deep impression on all those with whom he came into contact. We will never forget him.
