The LHC’s first long shutdown, LS1, is a marathon that began on 16 February and will take us through to the beginning of 2015. Just as Olympic marathon runners have a motto, Citius, Altius, Fortius, so the athletes of LS1 work to the mantra of Safety, Quality, Schedule. Four months into LS1, they have settled into their rhythm, and things are going to plan.
The first task of LS1 was to bring the LHC up to room temperature - this was achieved in just 10 weeks. In parallel, preliminary tests for electrical quality assurance and leaks revealed essentially the level of wear and tear we’d expect after three years of running. One slightly anxious moment came when we looked at the RF fingers – the devices that ensure electrical contact in the beam pipes as they pass from one magnet to the next. Those of you with long memories will recall that before start-up, some of these got damaged at warm-up. The good news today is that with all eight sectors tested, only two RF finger devices have sustained damage.
Once each sector of the machine reached room temperature, the teams could start opening up the interconnections layer by layer to reach the splices of the superconducting cables where the bulk of the work is needed. The main job for LS1 is to repair any splices that have an electrical resistance that would prevent the LHC from reaching higher energies, and to add shunts and an improved insulation and restraint system at every single one of the 10,170 main splices around the ring.
That work is well under way. Thanks to collaborations with teams from Athens and Wroclaw, along with support from JINR Dubna, the outermost layers of interconnects equating to almost four sectors are open. This allows the next teams, from Pakistan and field support units, to cut the sleeves, giving access to the busbar lines themselves. This process is proceeding at the required rate of over 10 interconnections per day. A significant milestone was reached on 24 April when the first shunt was soldered into place. Today, some 10% of the shunt work is complete.
There are many other tasks to be performed in LS1, including the installation of more pressure relief devices in the four sectors that were not done in 2009, the exchange of a number of magnets and consolidation of the feedboxes that take electricity into the LHC. There’s also work on our electrical substations on the Meyrin and Prévessin sites, as well as the consolidation of the entire upstream injector chain. All of this work is on schedule. You can follow progress on these dashboards, which are updated weekly, or by looking at the screens around the site where LHC page one is displayed when the machine is running. Safety, Quality, Schedule: with these three things always in mind, and with the Council’s approval last week of the 2014 budget, we’re on target to cross the LS1 finish line by the end of 2014, ready for a 2015 LHC re-start.