CMS Bulletin

INFRASTRUCTURE

During the last winter technical stop, a number of corrective maintenance activities and infrastructure consolidation work-packages were completed. On the surface, the site cooling facility has passed the annual maintenance process that includes the cleaning of the two evaporative cooling towers, the maintenance of the chiller units and the safety checks on the software controls. In parallel, CMS teams, reinforced by PH-DT group personnel, have worked to shield the cooling gauges for TOTEM and CASTOR against the magnetic stray field in the CMS Forward region, to add labels to almost all the valves underground and to clean all the filters in UXC55, USC55 and SCX5. Following the insertion of TOTEM T1 detector, the cooling circuit has been branched off and commissioned. The demineraliser cartridges have been replaced as well, as they were shown to be almost saturated. New instrumentation has been installed in the SCX5 PC farm cooling and ventilation network, in order to monitor the performance of the HVAC system and measure the actual power extracted by the cooling water. The two pumps of this circuit have been changed with more powerful ones, allowing the extension of the PC farm during the 2011 run.

The hardware of the low-voltage harmonic filters of the powering infrastructure has been reinforced with the addition of new modules for a total of additional 180 A. This would reduce the overheating of the low-voltage cabinets in USC55. A site general safety test, supervised by EN-EL personnel, has been completed as usual after the winter shutdown.

The winter shutdown was very busy for the CMS Infrastructure team, as all the major interventions had to be squeezed into a very short time, when the detector is off. Completing all the maintenance operations on the CMS Infrastructures has been a great achievement and the detector is now ready again for a long data-taking run.