The Latest from the LHC: Towards the big chill
With 6 sectors out of 8 at nominal cryogenic temperature (1.9 K= about -271 °C), the commissioning at the LHC is progressing well. According to the present schedule, the whole machine will be cold in about two weeks.

Final operations to fill the nitrogen tanks for cooling the last sector to 80K.
Only Sectors 3-4 and 6-7 are still in the cooling phase (currently between 60 and 20 K). As already mentioned in the previous update, as soon as a sector reaches the nominal cryogenic temperature, teams can start powering the magnets. At present, the current is flowing in the magnets of three sectors, while the remaining three will be powered in the coming two weeks.

The new layer of the Quench Detection System (QDS), installed in four sectors, is functioning well. In particular, the new software and hardware QDS components allowed teams to measure, with unprecedented accuracy and very quickly, the resistance of all the splices in Sector 1-2. The lower the resistance, the better the quality of the splice. All the measured resistances showed small values, and most are significantly below the original specifications. In addition, in the same sector, teams were able to test the new energy extraction system that dumps – twice as quickly as last year – the stored magnetic energy, thus better protecting the whole machine. Tests showed that both quadrupoles and dipoles are performing as expected.

During the weekend of 25-29 September, particles were extracted from the Super Proton Synchrotron (SPS) injector and injected into the transfer lines that link it to the LHC. Although the proton beams were dumped before entering the LHC, these crucial tests showed that the whole injection chain is ready and performs well. For the first time also, lead ions have arrived at the doorstep of the LHC.

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