The CERN convention was signed in 1953 by the 12 founding states Belgium, Denmark, France, the Federal Republic of Germany, Greece, Italy, the Netherlands, Norway, Sweden, Switzerland, the United Kingdom and Yugoslavia, and entered into force on 29 September 1954. The organization was subsequently joined by Austria (1959), Spain (1961-1969, re-joined 1983), Portugal (1985), Finland (1991), Poland (1991), Czechoslovak Republic (1992), Hungary (1992), Bulgaria (1999), Israel (2014) and Romania (2016). The Czech Republic and Slovak Republic re-joined CERN after their mutual independence in 1993. Yugoslavia left CERN in 1961.
Today CERN has 22 member states. Cyprus, Serbia and Slovenia are Associate Members States in the pre-stage to membership, and India, Lithuania, Pakistan, Turkey and Ukraine are Associate Members States.
Member states have special duties and privileges. They make a contribution to the capital and operating costs of CERN’s programmes, and are represented in the council, responsible for all important decisions about the organization and its activities.
Some states (or international organizations) for which membership is either not possible or not yet feasible are observers. 'Observer' status allows non-member states to attend council meetings and to receive council documents, without taking part in the decision-making procedures of the organization.
Over 600 institutes and universities around the world use CERN’s facilities. Funding agencies from both member and non-member states are responsible for the financing, construction and operation of the experiments on which they collaborate. CERN spends much of its budget on building machines such as the Large Hadron Collider and it only partially contributes to the cost of the experiments.
Observer States and organisations currently involved in CERN programmes include: Japan, the Russian Federation, the United States of America, the European Union, JINR, and UNESCO
Non-member states with co-operation agreements with CERN include Albania, Algeria, Argentina, Armenia, Australia, Azerbaijan, Bangladesh, Belarus, Bolivia, Brazil, Canada, Chile, China, Colombia, Costa Rica, Croatia, Ecuador, Egypt, Estonia, Former Yugoslav Republic of Macedonia (FYROM), Georgia, Iceland, Iran, Jordan, Korea, Malta, Mexico, Mongolia, Montenegro, Morocco, New Zealand, Peru, Saudi Arabia, South Africa, United Arab Emirates and Vietnam.
CERN also has scientific contacts with Cuba, Ghana, Ireland, Latvia, Lebanon, Madagascar, Malaysia, Mozambique, Palestinian Authority, Philippines, Qatar, Rwanda, Singapore, Sri Lanka, Taiwan, Thailand, Tunisia, Uzbekistan.
CERN employs just over 2500 people. The laboratory’s scientific and technical staff design and build the particle accelerators and ensure their smooth operation. They also help to prepare, run, analyse and interpret data from complex scientific experiments.
Some 12,000 visiting scientists from over 70 countries and with 105 different nationalities – half of the world’s particle physicists – come to CERN for their research.