QPS Signal Analysis Case studies from MPP and QPS Bob Flora
How do we Detect Quenches? Pressure Sensors Microphones Temperature Sensors Second Sound Fiber Optic Co-wound Cable Interferometer Bragg Diffraction Grating Backscatter Broadband Pulse Monochrome Pulse Sequence Electrical (Ohmic) Relative Balance Two Equal Elements (Los Vegas) Many Assorted Elements Absolute Current Measurement Differentiation dI/dt Inductive Model L(I) Voltage Measurement Missed Quenches must be pushed to Zero! False Quenches must be minimized.
Balance Detector (Analog) Two Equal Elements Main Dipoles B1 is balanced against B2 Main Quadrupoles half of one aperture is balanced against the other half U_QSO = -(U1+U2)
Dump Voltage +1V Diode Drop -1.2 Volts Entrance Voltage Exit Voltage Quench Signal (∑) x10 Heaters & Dump Fire! Diode Switches ON at -6 Volts
50˚K 433˚K 1.8˚K 77˚K 98˚K 147˚K 245˚K 18KW Peak Power
Quench Signal Test Ramp
Quench During Ramp Down
Hot Gas Quench
Imbalance During Quench Quench During Ramp Up
Tug of War
Vacillating Quench Signal
Typical Quench Behavior
Primary Quench Secondary Quenches
Symmetric Quench
Symmetric Quench Detail
Eddy Current Imbalance
Unquench Quench
Common Mode Error Switch Opens 30 Hz
First Beam Quench! Heater Quench Almost Collapses
Balance Detector (Digital) Two (almost) Equal Elements Individually Powered Magnets U_QSO = U1+U2
Quench While Ramping Up
Dipole Quench But Why Did the Heaters Fire???
Balance Error
Balance Detector (Distributed Digital) String against Reference Magnets Main Magnet Circuit Superconducting Bus
Balance Error
Balance Trip
Absolute Detector (Digital) Voltage and Current are Measured 600 Amp Circuits
QUENCH UQUQ U I R L R U L I+ R U dt d ( ) I+ R U U Q = U + L dt d ( ) I+ R U = U + L ( ) I+ R U Direct Quench Detection with Shunt Direct Quench Detection with Shunt SHUNT
Digianalog dI/dt Algorithm I (Hall Probe) I I dI/dt x 100
Superconducting Link Quenches
Main Circuit Energy Extraction
600 Amp Energy Extraction
Quench Heater Discharge
Current Leads