LHC latest schedule LMC no 24 LHC schedule

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LHC – latest schedule LMC no. 24

LHC – latest schedule LMC no. 24

LHC schedule 22 nd July – Katy Foraz Moved to 26/27 September by popular

LHC schedule 22 nd July – Katy Foraz Moved to 26/27 September by popular request LMC no. 24

v 3. 5 LMC no. 24

v 3. 5 LMC no. 24

Last LMC n n Results of TI 8 & TI 2 beam tests –

Last LMC n n Results of TI 8 & TI 2 beam tests – Brennan DFBA – flexibles – Laurent Tavian In conclusion, a high flow rate seemed to be the most plausible cause of the degradation; there would be no additional degradation for zero or reduced flow rate. ¨ The recommendation therefore was to stop or reduce the flow rate, and to repair the leaky DFBAs. A consolidation plan for the next long shut down (LSD) needed to be prepared (noting that the hoses on the QRL side were also considered vulnerable). ¨ n Update on bus segment resistance measurements in the three sectors 2 -3, 7 -8 and 8 -1 – Andre Siemko ¨ A second measurement of the RB in Arc 7 -8 had removed the outlier of the first measurement campaign - measurement error. LMC no. 24

LMC 24 n n The highest excess resistance was 12 micro. Ohm, and the

LMC 24 n n The highest excess resistance was 12 micro. Ohm, and the rms spread 5 micro. Ohm (“pretty high”). The RQ data for Arc 8 -1 had been very noisy, with an rms spread of 12 micro. Ohm, and a highest excess resistance of 28 micro. Ohm. This measurement had been repeated. Nonetheless the correlation of the two RQ A 81 measurements was close to zero, demonstrating that this measurement had been dominated by noise. An additional measurement had been conducted by the team of Nuria Catalan Lasheras using “Keithleys”. The reproducibility had been unsatisfactory here as well. LMC no. 24

LMC 24 n n Correspondingly, the RB measurements resolution at 80 K exhibited a

LMC 24 n n Correspondingly, the RB measurements resolution at 80 K exhibited a wide distribution for S 7 -8 and 2 -3 (the final RB results for S 8 -1 were not yet available). The measurement resolution was completely different from the one of the earlier campaign in S 4 -5. In summary, the reproducibility of the “biddle” bus segment resistance in 7 -8 and 8 -1 was much worse than in other sectors. No exceptionally high outliers had been detected, although S 7 -8 accommodated many early production magnets and early interconnections. LMC no. 24

LMC 24 n Andrzej Siemko elaborated that some magnets with long discontinuities between copper

LMC 24 n Andrzej Siemko elaborated that some magnets with long discontinuities between copper and busbar were located in this area, but had not shown up in the resistance measurements. The measured values of RQ segments in 7 -8 and 8 -1 were dominated by noise. LMC no. 24

LMC 24 n FLUKA model for bus bar simulations: ¨ Jörg Wenninger reported the

LMC 24 n FLUKA model for bus bar simulations: ¨ Jörg Wenninger reported the status of the FLUKA model for busbar simulations n A FLUKA model of the most critical busbar had been developed by Juan Blanco, Markus Brugger and Elias Lebbos. It modeled the cryostat next to Q 11. Noteworthy were the complicated lyras in the center and the Pb radiation shield. n Steve Myers stressed that the question of the possibility of a simultaneous magnet-busbar quench was the biggest factor for determining the beam energy before anything else. LMC no. 24

LMC 24 n Steve Myers sketched the draft agenda for the next, important meeting,

LMC 24 n Steve Myers sketched the draft agenda for the next, important meeting, which would summarize all factors relevant to the maximum LHC energy, such as energy extraction times, and the pertinent ECR. n Following the next meeting a decision would be taken by a restricted group of people. LMC no. 24