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Title: Magnetic field decay in model SSC dipoles

We have observed that some of our model SSC dipoles have long time constant decays of the magnetic field harmonics with amplitudes large enough to result in significant beam loss, if they are not corrected. The magnets were run at constant current at the SSC injection field level of 0.3 tesla for one to three hours and changes in the magnetic field were observed. One explanation for the observed field decay is time dependent superconductor magnetization. Another explanation involves flux creep or flux flow. Data are presented on how the decay changes with previous flux history. Similar magnets with different Nb-Ti filament spacings and matrix materials have different long time field decay. A theoretical model using proximity coupling and flux creep for the observed field decay is discussed. 10 refs., 5 figs., 2 tabs.
Authors:
; ; ; ; ; ;
Publication Date:
OSTI Identifier:
6611913
Report Number(s):
LBL-25139; CONF-880812-32
ON: DE89004791
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: Applied superconductivity conference, San Francisco, CA, USA, 21 Aug 1988; Other Information: Portions of this document are illegible in microfiche products
Research Org:
Lawrence Berkeley Lab., CA (USA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; MAGNETIC FIELDS; INSTABILITY; SUPERCONDUCTING MAGNETS; SUPERCONDUCTING SUPER COLLIDER; TIME DEPENDENCE; ELECTRICAL EQUIPMENT; ELECTROMAGNETS; EQUIPMENT; MAGNETS; STORAGE RINGS; SUPERCONDUCTING DEVICES 430300* -- Particle Accelerators-- Auxiliaries & Components; 420201 -- Engineering-- Cryogenic Equipment & Devices