Radiation-induced changes in magnetic properties of Nd-Fe-B permanent magnets

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · IEEE (Institute of Electrical and Electronics Engineers) Transactions on Magnetics; (USA)

DOI:https://doi.org/10.1109/20.34383· OSTI ID:5257645

Brown, R D; Cost, J R ^[1]

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1. Los Alamos National Lab., NM (USA)

The high remanence and intrinsic coercivity of Nd-Fe-B magnets make them desirable for use in accelerators. Use in the radiation environment of an accelerator requires that the sensitivity of these magnets to radiation be determined and the mechanisms responsible for degradation be understood. Small magnets were irradiated at the Omega West Reactor in a fast neutron flux of 4 X 10/sup 12/ n/cm/sup 2/ . s at a temperature of 350 {Kappa} (77{sup 0}C). At various time intervals during the irradiation, samples were removed from the reactor and the open-circuit remanence measured. The authors show that the rate of remanence decay decreases monotonically with increasing length-to-diameter (L/D) ratio for samples of the same material. Thus when comparing different materials, it is important that the samples have a fixed L/D ratio. Samples of different materials having an L/D ratio of 4.4 were neutronirradiated to study the decay of the remanence. Their results show that the sensitivity to radiation varies widely amount magnets from different vendors. Possible reasons for this variation are investigated and discussed.

• OSTI ID: 5257645
• Journal Information: IEEE (Institute of Electrical and Electronics Engineers) Transactions on Magnetics; (USA), Vol. 25:4; ISSN 0018-9464
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
36 MATERIALS SCIENCE
43 PARTICLE ACCELERATORS
ACCELERATORS
PERMANENT MAGNETS
BORON ALLOYS
MAGNETIC PROPERTIES
IRON ALLOYS
NEODYMIUM ALLOYS
PHYSICAL RADIATION EFFECTS
RADIOSENSITIVITY
FAST NEUTRONS
NEUTRON FLUX
OMEGA FACILITY
VARIATIONS
ALLOYS
BARYONS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
MAGNETS
NEUTRONS
NUCLEONS
PHYSICAL PROPERTIES
RADIATION EFFECTS
RADIATION FLUX
RARE EARTH ALLOYS
440200* - Radiation Effects on Instrument Components
Instruments
or Electronic Systems
360106 - Metals & Alloys- Radiation Effects
360104 - Metals & Alloys- Physical Properties
430300 - Particle Accelerators- Auxiliaries & Components