LS1 Report: all according to schedule
Last week, six magnets were replaced in LHC Sector 1-2. At Point 2, however, the maintenance work on the cooling towers combined with the very hot weather complicated the transport of the magnets as the increased humidity caused pools of water to form on the ground.
Picture 1: X-rays of the cryogenic distribution lines help identify the causes of leaks.
The interconnection train is advancing at an excellent pace. In Sector 5-6 the interconnection team has already begun re-soldering the sleeves of the M lines, but the team responsible for the consolidation of the electrical feedboxes (DFBAs) has had to overcome a problem associated with the tooling used to prepare the surfaces of the busbars in the DFBAs, which was not quite up to the job. The tools and procedures were modified and, happily, the problem was quickly resolved. The new tooling has just been validated, and the teams will be able to resume work on the DFBAs next week.
Two leaks had already been identified in the cryogenic distribution lines (QRL) of Sectors 4-5 and 7-8. Recent leak tests performed by the vacuum team have revealed a further five leaks in Sectors 3-4, 4-5, 6-7, 7-8 and 8-1. The X-rays (see picture 1) show that they all involve the same component, for which we have spares, and the faulty components are being analysed.
Picture 2: Drilling operations underway at UJ56 of the LHC.
The R2E work is also progressing at a good pace. All the power converters at Point 1 have been removed, and installation of the new electrical equipment is about to get under way. At Point 5, drilling is in progress between two LHC structures to allow the passage of four 14-metre sleeves measuring 40 cm in diameter (see picture 2). Although the risk of encountering a pocket of water seems to be excluded, the limited space in which the work has to be performed makes this a technically difficult operation.
On the injector side, the ventilation teams have removed the last two ventilation units from the PS this week. At the SPS, 15 of the 16 magnets have already been replaced while, for radioprotection reasons, the final one will not be replaced until the end of October. The work to replace the 18 kV transformers has also begun. Their transport during the nights of 24, 26, 27 and 28 June required the overhead tram lines to be disconnected under the supervision of the TPG and the Geneva police.
The cabling campaign, involving a total of no fewer than 700 km of cables (!), is also progressing quite quickly, in spite of repeated cable thefts in recent weeks.
