José Maria Los Arcos obtained his Master of Science in Physics in 1973 at the University of Zaragoza. The following year he joined the Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT) to which he devoted a major part of his career. In 1992, he became the Head of the CIEMAT Ionizing Radiation Metrology Laboratory.

He joined the BIPM in July 2012 and succeeded Penelope Allisy Roberts as the third Director of the BIPM Ionizing Radiation Department and as Executive Secretary of the Consultative Committee for Ionizing Radiation (CCRI). He was very familiar with the activities of the CCRI, having started to contribute to the work of the Committee in 1999 as CIEMAT representative for CCRI Section II: Measurement of radionuclides (CCRI(II)).

He spent five years at BIPM before going back to Spain, where he continued to work at CIEMAT as Scientist Emeritus and was involved in the International Fusion Materials Irradiation Facility DEMO Oriented Neutron Source (IFMIF-DONES) project.

We extend our condolences to his family, friends and colleagues during this difficult time. José Maria Los Arcos made great contributions to the metrology of ionizing radiation and will be remembered by his colleagues at the BIPM and the CCRI Community.