1. MQY-30 Test Result Report
H. Bajas, M. Bajko, V. Desbiolles, O. Dunkel, J. Feuvrier, L. Fiscarelli, C. Giloux, G. Kirby, F. Pincot, E. Ravaioli, F. Rougemont, P. Viret, G. Willering.

2. Main Goals of the Test
Magnet Memory test at 4.2 K to nominal current (3900 A)
Training at 1.9 K to target current (4950 A)
Unbalanced Magnetic Measurements
CLIQ protection study

4. Electrical scheme Facility/Magnet
Allows to separately power each aperture or both aperture in series.
Integration of two current leads at the middle of each apertures for CLIQ discharge.

5. All potentials respond Continuity assured
Electrical tests
All potentials respond
Continuity assured
Resistivity in accordance with OFH Copper (3%).
Estimate of the cable length per aperture:
=(2*((3.64*52)+(3.64*22)))*4 = 2155 mm

6. Hot Spot Temperature Estimate (adiabatic)
Miits (300 K) < 3 MA2.s

7. Current, voltage and dump resistor IMAX = 5 kA Rdump = 160 mW
UMAX = 800 V
LMag = 74 mH or 148 mH
tmag = Lmag / Rdump = 462 ms (or 925 ms)
HV passed at 1 kV
Cryostat Safe might not be safe pressure wise…
Pressure monitoring and provoked quenches
at intermediate current
Energy values
Estored = 0.5 * Lmag * IMAX 2 = 0.5*148*5^2 = 1.85 MJ
Eextracted = 0.20 * Estored = 370 kJ
Edeposited = 1480 kJ
Quench threshold, validation time & extraction switch inertia
vth= 10 mV
Dt = = 14.5 ms
Quench detection on:
-differential and direct signals
- connections
MIITs & Hot Spot Temperature
Miits = (Dt+0.5 tmag ). IMAX 2 = ( *925)*5^2=12 MA2.s
Magnet burnt
Should relies on the magnet resistance growth.
Careful check of the MIITs.

8. Quench Heater powering

9. Quench Heater powering
Need of re-wiring the circuit so assure redundancy on single coil test .
… powered in series, it yields:
R1 = 15.2 (15.8) W
R2 = 15.5 (14.9) W

10. Quench Heater signal survey
Voltage
Current
Resistance
Time constant
Joule Energy
Temperature
Quench Heater OK
Wrong reading (900V)
…Gain issue…

11. 1.9 K Endurance test performed for one hour
From April the 7th to the 17th
Three days of magnetic measurements
Shaft stop rotating during cooldown (Apt. 1) or powering (Apt. 2)
Cryogenics time: btw. 1 & 7 hours
CLIQ box issue: (stop test CLIQ)
Apt. 2
Apt. 1
Apt. 1 & 2
1.9 K
4.2 K

12. Example of quench (natural quench, 2 apertures)
Current and MIITs
Current and derivative

13. Example of quench (natural quench, 2 apertures)
Differential signal (protection)
Direction voltage

14. Computation of the inductive and resistive voltage and equivalent resistance.
Voltage derivation
Resistance derivation
Voltage to ground < 800 V
Resistance of the magnet (1.1 W) much higher than 160 mW dump resistor

15. 1.3 MJ dissipated in the bath during the magnet resistance growth (358 kJ dissipated by the dump).
Energetic approach
20% / 80%

16. How we came to it
Apt. 2
Apt. 1
Apt. 1 & 2

17. Energetic approach

18. Extrapolation of the dissipated energy as function of the current
HQ magnet

20. Pressure rise in the cryostat during the highest energy quenches.
Opening of the safety valve at 2.3 bar (to balloon).
No accumulation of the pressure in the cryostat thanks to large enough outlet and pressure valve gas release.

21. Inductance measurement

22. From resistance to resistivity to mean average temperature (copper as thermometer)…

23. Interesting resonant signal (direct) system
At QH firing (t ~ -20 ms)
At current extraction (t ~4 ms)

24. Quench Heater vs. CLIQ energy
CLIQ induces more heating of the coils than the quench heaters do.
Consequently Faster extraction

25. Conclusive remarks Magnet successfully tested.
Performance measured up to 4940 K K).
Energy, MIITS and Pressure controlled by provoked quenches at increasing current.
Quench Heater and CLIQ efficiencies compared up to 3 kA.
Unbalanced magnetic measurements limited to stuck shaft, need to improve assembly
Long Station Test facility qualified up to 1.3 MJ dissipated in the bath.

26. … Or adiabatic condition

27. Inductance fit

28. Energy: Quench Heater vs. CLIQ

29. Thermal cycle