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    Status of models, tools and experiments

    → Europe/Zurich
    6/R-012 - conference room (CERN)

    6/R-012 - conference room

    CERN

    40
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    Last week of Saskia, shall we have lunch on Friday?

     

    Saskia, DA with AC dipole and 40cm model

    Amplitude detuning measurements at 40cm are compared to model. Model has more non-linearities.

    Our usual AC dipole excitation is bad, it excites resonances. New Ac dipole tunes should be used.

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    Tobias,  90m

    with or without corrections did not make a difference.

    Local errors can be investigated (Lukas, Ana).

    No problem with dispersion measurement.

     

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    Jaime, Automatic local coupling correction

    (1 IR) Local matching on coupling reduces DQmin from 0.1 to 0.004, and global to 0.0004.

     In IR1 40cm we need to use different strs in the skew correctors -> Ion run!

     

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    Piotr, dispersion issue

    22nd of July, MD block 1,Beam 1. 

    On-momentum orbti measurement disagrees with offmomentum. By interpolate the off-momentum to zero one can

    compute the discrepancy along the accelerator. The plot shows that the discrepancy oscillates around the ring.

    This was almost the last time we saw this effect. More accurate plot to come.

     

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    Ana, Beta from amplitude

    Rejecting BPMs based on difference beta from amp - beta from phase. This is biasing the analysis.

     

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    Lukas, ESRF preparation and dispersion issue

    Dispersion measurement has 10% error bar for a dp/p=2e-4. A larger dp/p is clearly recommended.

    Dispersion errors were not considered for cuts. This has been now implemented, to be checked and committed.

     

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    Ewen, Considerations on non-linearity

    From IR measurements it is unclear that model octupolar errors can be reduced to improved agreement with

    measurements (Saskia analysis was suggesting so).

     

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