Speaker
Description
The East Area renovation project aimed at completing by the end of Long Shutdown-2 the consolidation and renovation of the CERN East Area, served by the Proton Synchrotron accelerator since more than 55 years. In particular, the Primary Area and the secondary beam lines of the East Area have been completely redesigned, highlighting some singular safety challenges.
The East Area receives a primary proton beam extracted from the Proton Synchrotron with a beam momentum of 24 GeV/c and an average beam intensity of 6.6e10 protons per seconds. Then, the primary beam impacts on dedicated targets located in the Primary Area, producing secondary beams from 15 GeV/c down to low beam momenta for the test beam lines T9, T10 and T11. The primary beam can also be directly transported through the T8 beam line in the East Area to the IRRAD and CHARM facilities.
The study details the challenges of the radiological assessment of the East Area renovation, starting by the dismantling of the old installation. Then, the focus is brought on the shielding calculations performed for the new design, the drivers of the radiological assessment, and the resulting compromises made to achieve prompt ambient dose equivalent rate levels compatible with the CERN radiological area classification. In addition, the layout has also been optimized with respect to residual radiation levels and air activation, to reduce the dose received during interventions. Finally, the study analyses the measurements made with the new radiation monitor network, both during the commissioning phase and the first year of operation.
The measurement data from the radiation monitors coupled with the shielding calculations performed with FLUKA for the different scenarios considered for the study has proven to provide useful feedback during the commissioning and beam optimization periods.