We received news of the passing of Paul Kuijer with great sorrow. Paul was a senior experimental physicist at Nikhef and played an important role in the ALICE experiment at CERN. During the last years of his career, Paul had turned his attention mostly towards the ET Pathfinder project within the Gravitational Waves group at Nikhef and the University of Maastricht. While he officially retired in 2024, he still came to Nikhef weekly and continued to contribute to several projects.

Paul worked on his PhD at the University of Amsterdam with the MARK-J experiment at the PETRA accelerator in DESY, Hamburg, where he performed a search for the top quark and measured the strong coupling constant using electron–positron collisions. In 1987, he joined Utrecht University as an assistant professor and worked on various experiments at the Institute for Nuclear Physics. In 1994, he became a member of the ALICE experiment at CERN and worked on the proposal and technical design report for the Silicon Strip Detectors (SSD), a joint project realised with laboratories in Finland, France, Italy, The Netherlands, Russia and Ukraine. In 2008, he became the first ALICE run-coordinator and, in 2009, he was selected as deputy spokesperson of the ALICE collaboration.

When his role as deputy spokesperson came to an end, he again worked on silicon detectors at Nikhef, overseeing the maintenance of the SSD, and, until 2019, was the project leader for the upgrade of the new ALICE Inner Tracking System.

In addition to working on hardware, Paul had a strong passion for physics, supervising many PhD students throughout his career. Everyone who worked with him remembers him fondly and with respect. He was an excellent scientist and a gentle, reliable person who would always make time to discuss physics and help with the daily practical problems encountered by technicians, PhD students or staff members. Paul was known for his hands-on approach; he often had a small project on the go, and he never shied away from new challenges. He was very approachable and always made time to discuss physics or simply chat with students and staff alike.

We will greatly miss his friendly and warm personality. Paul leaves a great void in our community. Our thoughts are with the family, friends and close colleagues that Paul leaves behind.

His friends in the ALICE collaboration