The latest from the LHC

The LHC will run with an energy of 3.5 TeV per beam when it starts up in November this year. The 80 K resistance measurements on the copper stabilizer of the superconducting busbars were completed in the remaining sectors, Sectors 8-1 and 2-3. No abnormally high resistance measurements were found, indicating that no further repairs are necessary for safe running.

Detailed analysis of the resistance data from the entire ring determined a safe initial energy of 3.5 TeV per beam. Once a significant data sample has been collected and the operations team has gained experience in running the machine, the energy will be taken towards 5 TeV per beam. More information is available in the recent press release

Following the helium leaks into the insulation vacuum in Sectors 2-3 and 8-1 (see previous update) the cause of the leak in Sector 2-3 has been confirmed as the flexible hose. This has now been replaced by a solid tube, with an expansion loop to mitigate the effect of contraction due to cooling. In preparation for re-cooling the sector, both the insulation and beam vacuum are currently being tested. The final subsector in 8-1 is also now warm, and work will start to remove the flexible hose once the temperature has stabilized.

The Vacuum group have also leak-tested the final subsector in Sector 6-7, completing vacuum validation for the entire ring outside Sectors 2-3 and 8-1. Work is also currently ongoing to install the ‘pressure release springs’ in the sectors without new pressure release ports (see previous update).

A short-circuit to ground occurred in the dipoles circuit of Sector 6-7 on 20 August. The cooling of the sector had to be stopped. The repairs will be carried out in the coming week.

With the present planning Sector 6-7 was due to be ready 2 weeks before the last Sector 8-1, so there will be minimal or no effect on the overall date for first injections.