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    16th Quench Behavior Team meeting

    → Europe/Zurich
    30/7-018 - Kjell Johnsen Auditorium (CERN)

    30/7-018 - Kjell Johnsen Auditorium

    CERN

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    Date: 2017-01-17, 09.00-10.00

    Place: 30-7-018

    Presents: G. Willering, A. Verweij, A. Siemko, P. Hagen, R. Schmidt, D. Tommasini, M. Bajko, E. Todesco, R. V. Weelderen, D. Mapelli

    Shape of quench distributions [D. Mapelli]

    Dario has been working on the shape of the quench probability distributions of the production (SM18 data). He proposes a Gaussian distribution multiplied by a parabolic term (x-m)2 , showing that in most cases this fits well the data, accounting for the observed asymmetry and removing the non-physical feature of the Gaussian of having finite probability (even though very small) at very large values. The fit is now used by Ezio to propose the extrapolations at 7 TeV.

    Update on analysis of training towards 7 TeV [E. Todesco]

    Ezio presents the comparison between the expected training of sectors 34 and 45 at 11.45 kA and 11.55 kA respectively, and the data gathered during the training campaign of end 2016. One observes 21 first quenches against 34 expected. This lower number is just below the two sigma level of the forecast. Therefore, the 2016 data show a slightly faster training than expected. Based on the new set of data, and on the new distribution fit proposed by Dario, the new estimate of first quenches is between 400 and 500 quenches (against a previous value of 520 to 580).

    The 1000 series is still out of the radar, since we had only 1 quench above 11.08 kA. So it is hard to guess if the 1000 series will be negligible in the LHC training (as assumed in January 2016 estimate: 5%, i.e. 20 quenches), or if it will contribute with the same rate of the second virgin quench, or of the first quench after thermal cycle (18%, i.e. 70 quenches).

    The second quench is clearly visible, and 10 out of the 32 quenches above 11.08 kA are second quenches. They are all from 3000 series. According to the fraction of production affected by this phenomenon, one can expect between 70 and 90 second quenches of the 3000 series to reach 12 kA.

    Summarizing, the new estimate is between 500 and 600 quenches, including second quenches.

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