CMS Bulletin

MAGNET

The magnet is fully stopped and at room temperature. The maintenance works and consolidation activities on the magnet sub-systems are progressing.

To consolidate the cryogenic installation, two redundant helium compressors will be installed as ‘hot spares’, to avoid the risk of a magnet downtime in case of a major failure of a compressor unit during operation. The screw compressors, their motors, the mechanical couplings and the concrete blocks are already available and stored at P5. The metallic structure used to access the existing compressors in SH5 will be modified to allow the installation of the two redundant ones. The plan is to finish the installation and commissioning of the hot spare compressors before the summer 2014.

In the meantime, a bypass on the high-pressure helium piping will be installed for the connection of a helium drier unit later during the Long Shutdown 1, keeping this installation out of the schedule critical path.

A proposal is now being prepared for the consolidation of the compressor lubricant separator unit, against the risk of polluting the downstream helium piping with the lubricant in case of a degradation of the filtering units.

The overhaul of the two existing compressors and their motors is planned for the end of 2013, and the re-installation will take place in mid-March 2013.

The low-voltage electrical distribution for the cryogenic process control has been consolidated. The consolidation works for the redundant compressors on the 3.3 kV distribution network at Point 5 will take place in the second half of 2013 and extend until the beginning of 2014, before the redundant compressors will be commissioned.

For the other magnet sub-systems, namely the vacuum pumping groups, the magnet control and safety systems and the powering circuit, minor consolidations are planned. A thorough maintenance will be made well ahead of the scheduled magnet restart.

A refurbishment of the data acquisition system for the magnet coil instrumentation is now discussed together with CEA/Saclay.

The instrumentation on the yoke will be completed with about 60 new Hall probes, part of them are ready to be installed on the barrels.