This year, CERN will be closed from Wednesday, 22 December 2021 to Tuesday, 4 January 2022 inclusive. The first working day of the new year will be Wednesday, 5 January 2022.

As is the case every year, the only persons who will be entitled to enter the CERN site during the end-of-year closure are those who have been authorised to do so for strictly professional reasons (stand-by service or indispensable maintenance work). The COVID-19-related restrictions remain applicable.

A specific e-group records all such authorised personnel. Managers (department heads, group leaders, contract supervisors, etc.) and experiments’ technical coordinators are responsible for submitting the names of the persons concerned to their department’s designated person for updating the e-group by Tuesday, 21 December 2021. The procedure is documented on the service portal.

Unlike in previous years, it is no longer necessary to include members of the personnel of outside companies in these departmental/experiment lists. Any members of the personnel of outside companies who are required to work on the CERN site during the closure must have a valid notice of work to be done outside normal working hours (AET). Please note that AETs must be limited to the time needed to perform the work in question or, in the case of annual AETs, must not extend beyond 21/12/2022. As a reminder, all 2021 AETs will end on 17/12/2021 at the latest.

During the period when the Laboratory is closed, from 22 December onwards, any members of the CERN personnel who need to enter the CERN site for an urgent reason and without prior authorisation from their department or their experiment’s technical coordinator will be obliged to submit an access request ("CERNXMAS" permission request), which may be signed by the Security service or the CCC (TI) after its legitimacy has been assessed. The “CERNXMAS” permission option will not be available in the ADAMS system until 22 December. This provision does not apply to members of the personnel of outside companies, since they must have a valid AET.

We would also like to remind you that all CERN services, including the restaurants and the library, will be closed during the end-of-year closure.

We thank you for your cooperation and wish you all a very happy holiday.