Title :
Quench detection and protection of the wide bore 900 MHz NMR magnet at the National High Magnetic Field Laboratory
Author :
Dixon, I.R. ; Markiewicz, W.D. ; Murphy, P. ; Painter, T.A. ; Powell, A.
Author_Institution :
National High Magnetic Field Lab., Tallahassee, FL, USA
fDate :
6/1/2004 12:00:00 AM
Abstract :
A wide bore, high resolution NMR magnet with a proton resonance frequency of 900 MHz, field of 21.1 T, and stored energy of 40 MJ has been designed and fabricated at the NHMFL. The magnet has five Nb3Sn and five NbTi coils, each of which contains stainless steel strip heaters. An active protection system with analog quench detection circuitry is employed to determine the onset of a quench and to subsequently open a superconducting protection switch and energize a portion of the strip heater network. A passive protection system with diode sets and shunting resistors exist for redundancy. Details of the protection system are presented and its performance during the magnet´s bucket test is discussed.
Keywords :
niobium alloys; nuclear magnetic resonance; protection; quenching (thermal); superconducting coils; superconducting magnets; superconducting switches; tin alloys; titanium alloys; 21.1 T; 40 MJ; 900 MHz; National High Magnetic Field Laboratory; Nb3Sn; NbTi; active protection system; analog quench detection circuitry; bucket test; diode sets; high resolution NMR magnet; magnet bucket test; passive protection system; proton resonance frequency; quench detection; quench protection; shunting resistors; stainless steel strip heaters; strip heater network; superconducting magnets; superconducting protection switch; wide bore NMR magnet; Boring; Laboratories; Magnetic fields; Magnetic resonance; Nuclear magnetic resonance; Protection; Strips; Superconducting coils; Superconducting magnets; Switches; Magnet; protection; quench; superconductivity;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2004.830547
