The latest from the LHC

30-01-2009.

Dipole MB2334, which was found to have an internal splice resistance of 100 nano-ohms and was removed from Sector 1-2 last week has now been opened. It has been confirmed that there was a lack of solder on the splice joint.

Each sector has more than 2500 splices and a single defective splice can now be identified in situ when the sector is cold. Using this method another magnet showing a similar defect has been identified in sector 6-7. This sector will be warmed and the magnet removed. The warm up of this additional sector can be performed in the shadow of the repair to sector 3-4 and will therefore not add any additional delay to the restart schedule.

In parallel, three dipoles and the first replacement short straight section (SSS) have been installed in sector 3-4: this takes the total number of installed replacement magnets to nine. It has also been a good week for cryostating in SMI2, with three dipoles and two SSS completed.

The consolidation work to install additional pressure release nozzles on the dipoles is going ahead. These new, larger nozzles have been designed jointly by TE and EN departments. For the tunnel implementation extra resources are being organised, both from Industrial partners and from a Dubna team through a PH-ATLAS-TE collaboration. These nozzles will allowed greater rate of helium escape in the event of a sudden increase in temperature.

In sector 5-6 RF ball testing is finished, showing three “plug-in" modules (PIMs) with buckled RF fingers, which are being replaced (see previous breaking news).

Dipole MB2334, which was found to have an internal splice resistance of 100 nano-ohms and was removed from Sector 1-2 last week has now been opened. It has been confirmed that there was a lack of solder on the splice joint.

Each sector has more than 2500 splices and a single defective splice can now be identified in situ when the sector is cold. Using this method another magnet showing a similar defect has been identified in sector 6-7. This sector will be warmed and the magnet removed. The warm up of this additional sector can be performed in the shadow of the repair to sector 3-4 and will therefore not add any additional delay to the restart schedule.

In parallel, three dipoles and the first replacement short straight section (SSS) have been installed in sector 3-4: this takes the total number of installed replacement magnets to nine. It has also been a good week for cryostating in SMI2, with three dipoles and two SSS completed.

The consolidation work to install additional pressure release nozzles on the dipoles is going ahead. These new, larger nozzles have been designed jointly by TE and EN departments. For the tunnel implementation extra resources are being organised, both from Industrial partners and from a Dubna team through a PH-ATLAS-TE collaboration. These nozzles will allowed greater rate of helium escape in the event of a sudden increase in temperature.

In sector 5-6 RF ball testing is finished, showing three “plug-in" modules (PIMs) with buckled RF fingers, which are being replaced (see previous breaking news).

 

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