However, access is given to persons outside CERN upon request when there is justified interest. They have free access to documents and files of a purely scientific nature which have not been subject to restricted distribution and which do not contain any confidential information. In principle, they have to send a written request to the Archivist. There exist three levels of access according to the type of archived material. The level of access to a document or file is generally decided by the creator of the document or file and is indicated in the catalogue of the CERN Archives.
Free access applies to the majority of the scientific and technical material archived.
Restricted access applies to documents with restricted distribution, to files containing administrative documents, in particular correspondence, and to some declassified confidential material. Restricted access can be imposed by the originator or by CERN Management. Protected access applies to confidential material for a period of thirty years, which may be extended in exceptional cases to fifty years. The catalogued records describe the documents and files held in t he CERN Archives, indicating their access status. All users must contact the Archivist to gain access to the CERN Archives.