1. QPS Signal Analysis Case studies from MPP and QPS 04.09.2008 Bob Flora

2. 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.

3. 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)

4. Dump Voltage +1V Diode Drop -1.2 Volts Entrance Voltage Exit Voltage Quench Signal (∑) x10 Heaters & Dump Fire! Diode Switches ON at -6 Volts

5. 50˚K 433˚K 1.8˚K 77˚K 98˚K 147˚K 245˚K 18KW Peak Power

6. Quench Signal Test Ramp

7. Quench During Ramp Down

10. Hot Gas Quench

11. Imbalance During Quench Quench During Ramp Up

17. Tug of War

18. Vacillating Quench Signal

20. Typical Quench Behavior

24. Primary Quench Secondary Quenches

26. Symmetric Quench

27. Symmetric Quench Detail

28. Eddy Current Imbalance

29. Unquench Quench

30. Common Mode Error Switch Opens 30 Hz

31. First Beam Quench! Heater Quench Almost Collapses

32. Balance Detector (Digital) Two (almost) Equal Elements Individually Powered Magnets U_QSO = U1+U2

35. Quench While Ramping Up

36. Dipole Quench But Why Did the Heaters Fire???

37. Balance Error

41. Balance Detector (Distributed Digital) String against Reference Magnets Main Magnet Circuit Superconducting Bus

42. Balance Error

43. Balance Trip

44. Absolute Detector (Digital) Voltage and Current are Measured 600 Amp Circuits

45. 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

46. Digianalog dI/dt Algorithm I (Hall Probe) I I dI/dt - - + + x 100

69. Superconducting Link Quenches

73. Main Circuit Energy Extraction

83. 600 Amp Energy Extraction

88. Quench Heater Discharge

91. Current Leads