CMS Bulletin

INFRASTRUCTURE

The CMS Infrastructures teams are preparing for the LS1 activities. A long list of maintenance, consolidation and upgrade projects for CMS Infrastructures is on the table and is being discussed among Technical Coordination and sub-detector representatives. Apart from the activities concerning the cooling infrastructures (see below), two main projects have started: the refurbishment of the SX5 building, from storage area to RP storage and Muon stations laboratory; and the procurement of a new dry-gas (nitrogen and dry air) plant for inner detector flushing. We briefly present here the work done on the first item, leaving the second one for the next CMS Bulletin issue.

The SX5 building is entering its third era, from main assembly building for CMS from 2000 to 2007, to storage building from 2008 to 2012, to RP storage and Muon laboratory during LS1 and beyond. A wall of concrete blocks has been erected to limit the RP zone, while the rest of the surface has been split between the ME1/1 and the CSC/DT laboratories. Access doors and floor surface have been prepared, installation of basic infrastructure such as power sockets, lighting spots, extraction units, washing facilities etc. is under way. A specific water-cooling and gas-distribution network will also be put in place. The area will be fully equipped with infrastructures before LS1 starts and will receive the first components from CMS at the very beginning of the shutdown.

Regarding cooling infrastructures, a few cooling incidents disturbed the data acquisition during summer, most of them due to failure of acquisitions sensors. A deep investigation by the EN/CV teams has followed and systems have been modified or prepared for modifications to be implemented during LS1.

Components for the consolidation activities foreseen on the Yoke and Rack circuits have been purchased, and the projects involving major reworks of EN/CV circuits have been agreed (in particular the study for the decoupling of the magnet Busbar circuit from any other system).

For the C₆F₁₄ cooling circuits, a review held on 4 October within the Tracker community has endorsed the design for modification proposed by EN/CV/DC. Most components have been procured and the 3D models to integrate the mechanical modifications are ready.

In addition to consolidation and maintenance activities, the construction of a brand new system has started: the CO₂ cooling plant for the upgrade of the pixel detector. For this system, a lot of work is going on for the integration of the necessary ancillary services for the installation of the final system at P5.

Image 1: Layout of the SX5 building at P5 (courtesy G. Duthion).