It is with great sadness that the International Commission on Radiation Units and Measurements (ICRU) announces the passing of Dan Jones who was a member of ICRU for 12 years. He was elected †o the Commission in 2002. He was also a member of the Board of ICRU and served as Secretary of the Board from 2012  to 2014.

 During the period of his membership 25 ICRU reports were produced. Dan was actively involved in almost all of them and contributed scientific input in many of these reports. Being a medical physicist with extraordinarily broad knowledge in nuclear physics and nuclear technology as well as in medical radiology enabled him to make sound and critical contributions to reports with a physical and medical focus. His reviews of draft ICRU reports were detailed, critical, and constructive, which contributed towards scientific coherence within a given report and consistent with ICRU reports at large.

 Dan was born in 1943 in Cape Town, South Africa and received his M.Sc. in Physics, his M.Sc. in Medical Physics, and  also a Ph.D. in Nuclear Physics  from the University of Cape Town. His professional career was spent mainly at the iThemba Laboraties for Accelerator Based Science in Somerset West, South Africa where he was the Head of the Group on Medical Radiation. Dan had an impressive international career. Loyal to his colleagues and gifted with an encyclopedic knowledge of physics and nuclear techniques and their applications in medicine or engineering with experience in management made him a most sought after consultant and collaborator to international institutions and organizations such as the International Atomic Energy Agency and the World Health Organization, universities, and governments. His many awards included being nominated as Honorary Professor at the University of Cape Town.

Dan, big in physical stature, rigorous, serious, and demanding in his work habits may initially have appeared intimidating. He was a born leader, enterprising and imaginative, a master of organization who motivated his associates by his example and high expectations. Dan could be trusted in the punctual  performance of duties and assignments. Once the work was done, his playful side came to life. Spreading good humor to everyone, his famous burst of laughter will never be forgotten. Dan loved to get together with friends over a good meal in a restaurant or prepared by himself. He had many friends around the world from his extensive collaborations and consulting. He loved to travel and he and his wife Diana were wonderful hosts, guiding visitors to the tourist and gastronomic delights of South Africa.

 His contributions to ICRU reflected the breadth of his knowledge and experience around the world with his connections to so many of the most renowned scientists. Dan will be missed and remembered for his contributions to science and for his friendship and many enjoyable encounters.

 ICRU offers its condolences to his wife Diana and his family and friends.

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