The latest from the LHC


Sector 6-7 has now been warmed up to room temperature and work is starting to open the interconnections between the faulty magnet and its neighbours. The magnet, which was found to have high internal splice resistance, will be removed and investigated.

The first prototype for the new anchoring system for some of the short straight sections (SSS) has been installed on a magnet in the tunnel. The new supports will be fitted to the arc SSS that have vacuum barriers in order to provide extra strength.

During the incident in sector 3-4 last September, the pressure of released helium on the vacuum barriers caused some of the SSS to be moved from their anchoring, which caused collateral damage some distance from the original fault. Together with the new pressure relief system, the extra anchoring is part of the consolidation program for the machine.

Once the green light is given production will start immediately. The new system will be installed in all relevant magnets in the tunnel, 104 in total.

A review of the Quench Protection system

Last week the Enhanced Quench Protection system had a full review from a panel made up of experts from other HEP labs from around the world, including the American laboratories FNAL and BNL, the German laboratory DESY and the ITER organization.

The Enhanced Quench Protection system has two separate parts: firstly to detect and protect against abnormally high resistance “splices” and secondly the detection of a symmetric quench. The planning schedule was reviewed in order to define priorities between these two parts, both of which need to be complete before the restart at the end of September this year.

The review also covered areas such as the technical details of the implementation of the new system, how well it will perform during operation and how ‘robust’ it will be after years of service.

In the preliminary report the panel found that: “The Machine Protection staff have demonstrated a deep understanding of the issues involved in the design of the High Resistance Splice Detection System.” It has “full confidence that the new system will have the ability to give early warnings for suspicious splices measured at the level of 1 nano-ohm.” And that “The Symmetric Quench Protection System, once its design is complete, will be able to detect quenches at twice the normal detection level.”

There will be more details on the Report, and the Enhanced Quench Protection system in the next issue of the Bulletin.


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