Why do we have to wear a national dosimeter in addition to a CERN dosimeter?

All European countries have transposed the EURATOM directives concerning workers occupationally exposed to ionising radiation into their national regulations. One of these directives is the obligation for the employer to ensure dosimetry and medical follow up of his exposed workers. This obligation is present for instance in the Swiss ordinance on radiation protection, or in the French labour regulations (code du travail). It is thus a legal obligation for the employer. In parallel CERN requires to control that the dose limits of its own radiation protection code are properly observed. For this purpose the Organisation uses its own dosimeters that are directly readable. The doses that are registered by CERN cannot be transmitted to all CERN member countries and beyond because the Dosimetry Service is not accredited in these countries.