Testing of the Superconducting Solenoid for the Fermilab Collider Detector

The 3 m Φ × 5 m long × 1.5 T superconducting solenoid for the Fermi- lab Collider Detector has been installed at Fermilab and was tested in early 1985 with a dedicated refrigeration system. The refrigerator and 5.6−Mg magnet cold mass were cooled to 5 K in 210 hours. After testing at low currents, the magnet was charged to the design current of 5 kA in 5−MJ steps. During a 390 A/min charge a spontaneous quench occurred at 4.5 kA due to insufficient liquid helium flow. Three other quenches occurred during “slow” discharges which were nevertheless fast enough to cause high eddy current heating in the outer support cylinder. Quench behavior is well understood and the magnet is now quite reliable.