Protection system for inductively coupled magnets [and experience in MRI magnet systems]

Author

Schwall, R.E.

Author_Institution

IBM Thomas J Watson Res. Center, Yorktown Heights, NY, USA

Volume

27

Issue

2

fYear

1991

fDate

3/1/1991 12:00:00 AM

Firstpage

1700

Lastpage

1703

Abstract

A completely passive protection system for complex assemblies of superconductive magnets is presented. Quench-back heaters are used to initiate normal zones in multiple coils. Silicon diodes operating at 4.5 K are utilized to permit rapid charging and discharging of the magnet system, to protect the persistent current switches, and to prevent the long-lived field disturbances associated with resistively shunted magnets. Protection modules employing a self-limiting heater are used to provide the rapid response necessary to protect inductively coupled shim coils while maintaining protection system integrity during a worst-case quench of the main coils. Operating experience with this protection technique on three Magnetic Resonance Imaging (MRI) magnet systems is reported

Keywords

biomedical NMR; biomedical equipment; protection; superconducting magnets; 4.5 K; MRI magnet systems; Si diodes; cold diodes; complex assemblies; inductively coupled magnets; passive protection system; quench-back heaters; resistively shunted magnets; self-limiting heater; shim coil-protection; superconductive magnets; Assembly systems; Couplings; Diodes; Magnetic resonance imaging; Magnets; Persistent currents; Protection; Silicon; Superconducting coils; Superconductivity;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.133516

Filename

133516