Mechanical strain measurements on MQXFS1 Magnet using CERN system M.Guinchard and P.Grosclaude European Organization for Nuclear Research (CERN) 27 April, 2016 Thanks to Thomas Strauss and Fermilab Team for their help

Outline CERN DAQ System principle Measurements during assembly phases and cool down Behaviour during quenches Why instability on CERN strain gauge signal ? Investigations Conclusion 27/04/2016 M.Guinchard and P.Grosclaude2

CERN DAQ System principle 27/04/2016 M.Guinchard and P.Grosclaude3 Current Voltage

Measurements during assembly phases and cool down 27/04/2016 M.Guinchard and P.Grosclaude4

Behavior during quenches : Azimuthal strain on the Shell 27/04/2016 M.Guinchard and P.Grosclaude5

Behavior during quenches : Azimuthal strain on the coils during Q#3 27/04/2016 M.Guinchard and P.Grosclaude6

Why instability on CERN strain gauge signal? Strain gauges behaviour : – Low frequency effects (Confirmed by FFT analysis) – Reproducible during ramps if no quench – No reproducible after quench – Correlation between Azimuthal et Longitudinal direction – No plastic deformation (back to initial strain) Our feeling : – Issue with thermal compensator stability (fixation) – Interaction with the test bench – Issue with AC Power Supply (Issue with phase shift detection due to high current ?) In order to better understand the behavior, we decided to change the configuration : – Initial configuration : 4 Half bridges in azimuthal and longitudinal directions. – New configuration : 4 Quarter bridges in azimuthal direction and 4 Quarter bridges on the compensators in Z direction. 27/04/2016 M.Guinchard and P.Grosclaude7

Investigations Comparison AC / DC Voltage in quarter bridge 27/04/2016 M.Guinchard and P.Grosclaude8 Behavior modifications of the compensators

Conclusion 27/04/2016 M.Guinchard and P.Grosclaude9

Conclusion Good agreement between both systems on the shell ; Good agreement between both systems on the coils ; AC to DC changes solve the issue on the coils ; Possible explanations : – Issue in the phase detection closed loop of the DAQ with high current (Previously validated up to 10T); – Cable effects; – Strain gauges – wires connections. Next steps : – 4 coils of MQXFS2 instrumented in quarter bridge configuration; – Additional compensators will be placed to perform additional tests with cables; – Investigation for FOS using in progress, discussion with the DAQ supplier. 27/04/2016 M.Guinchard and P.Grosclaude10

Thank you for your attention 27/04/2016 M.Guinchard and P.Grosclaude11

Stability measurements over 3h 27/04/2016 M.Guinchard and P.Grosclaude12

DC component removing 27/04/2016 M.Guinchard and P.Grosclaude13

Behaviour during quenches : Correlation between Azimuthal and Longitudinal strain 27/04/2016 M.Guinchard and P.Grosclaude14

Behaviour during quenches : Azimuthal strain on Coil /04/2016 M.Guinchard and P.Grosclaude15

Behaviour during quenches : Correlation between Coil and Shell in azimuthal direction 27/04/2016 M.Guinchard and P.Grosclaude16