Field enhancement in superconducting solenoids by holmium flux concentrators

Schauer, W.; Arendt, F.

doi:10.1016/0011-2275(83)90198-4

Cited by 14 publications

(6 citation statements)

References 1 publication

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“…Holmium is a rare-earth metal which undergoes an anti-ferromagnetic to ferromagnetic phase transition with decreasing temperature at around approximately 20 K. In the ferromagnetic state, and at 4.2 K, holmium has the highest saturation magnetisation of any element: µ 0 M s = 3.9 T. A 1958 paper by Rhodes, Spedding, and Levgold characterised the magnetic dependence of holmium on temperature (down to 4.2 K) and on applied magnetic field (up to µ 0 H = 1.6 T) [29]; these magnetic measurements were performed on a torus of rectangular cross-section around which a normal conductor was wound and a current applied [30]. A 1983 paper by Schauer and Arendt then characterised the B-H curve of holmium at 4.2 K in a much stronger applied magnetic field (up to µ 0 H = 12.5 T) [31]; in this case, two holmium cylinders were placed as flux concentrators within a Nb 3 Sn superconducting solenoid. A gap between the cylinders of 5.5 mm allowed field measure-ments to be taken using a Hall probe.…”

Section: Rare-earth Superconducting Magnetsmentioning

confidence: 99%

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Compact Rare-Earth Superconducting Cyclotron

Kelly,

Owen,

Antaya

et al. 2019

Preprint

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The use of superconductivity is well-known as a method to increase the average field of a cyclotron and thereby to allow a substantial reduction of its size and mass. We present a compact high-field design for the first superconducting cyclotron with rare-earth (holmium) poles. Our design supports stable acceleration of protons to E k = 70 MeV with no significant limit in beam current, suitable for wide applications in ocular therapy, isotope production, radiobiological studies and nuclear physics.

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Section: Rare-earth Superconducting Magnetsmentioning

confidence: 99%

“…2. Holmium B-H curve at 4.2 K; data taken from Schauer and Arendt [31] and Rhodes et al [29], fit from Norsworthy [32]. The onset of saturation at 3.9 T may be seen.…”

Section: Rare-earth Superconducting Magnetsmentioning

confidence: 99%

Compact Rare-Earth Superconducting Cyclotron

Kelly,

Owen,

Antaya

et al. 2019

Preprint

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“…Magnetoresistive heat switches as suggested in [2] are used instead of mechanical or gas-gap switches to address size and reliability issues. Also, miniature magnets (not pictured) with flux-concentrating rare earth metals holmium and vanadium permendur are used to provide the necessary magnetic fields [3,4]. Simulations using data from [5] for the material-based heat switch and the known performance of the paramagnetic salt ferric ammonium alum (F AA) have shown that the MADR will be able to cool an experimental stage to below 0.1 K from thermal reservoirs of less than 5 K. Unlike conventional ADRs, which use a single salt pill to cool a cold stage in one shot, the MADR is designed to alternately operate 2 salt pills rapidly.…”

Section: A Novel Approachmentioning

confidence: 99%

A miniature adiabatic demagnetization refrigerator with a magnetoresistive heat switch

Supanich

Timbie

2002

AIP Conference Proceedings

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We present the design of a novel, miniature ADR with no moving parts, which could be used to cool detectors for astrophysics research, semiconductor analysis, and mass spectrometry. The miniature ADR relies on the development of a magnetoresistive heat switch. We present measurements of the thermal conductivity of a single-crystal tungsten heat switch at temperatures below 4 K and magnetic fields below 0.9 Tesla.

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“…Holmium has one of the highest known magnetic moments. It has been used to create the strongest artificially generated magnetic fields when placed within high-strength magnets as a magnetic pole piece or magnetic flux concentrator [99,100]. It can also be used as a neutron absorber in nuclear reactors.…”

Section: Holmium-erbium-thulium-ytterbiummentioning

confidence: 99%

Rare Earths and the Balance Problem: How to Deal with Changing Markets?

Binnemans

Jones

Müller

et al. 2018

J. Sustain. Metall.

232

136

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The balance between the market demand and the natural abundance of the rare-earth elements (REEs) in ores, often referred to as the Balance Problem (or the Balancing Problem), is a major issue for REE suppliers. The ideal situation is a perfect match between the market demand for and the production of REEs, so that there are no surpluses of any of the REEs. This means that the rare-earth industry must find new uses for REEs that are available in excess and search for substitutes for REEs that have either limited availability or are high in demand. We present an overview of the trends in the applications for the different REEs and show that the demand for REEs for use in magnets, catalysts, and alloys is still increasing, while the application of REEs in polishing agents, glass, and ceramics are stable. On the other hand, the use of REEs in nickel-metal-hydride (NiMH) batteries and lamp phosphors is decreasing. These changes in the REE market have an influence on the Balance Problem, because the REEs that can be recycled from fluorescent lamps, cathode-ray tubes (CRTs), and NiMH batteries have to be at least partly reused in other applications. Magnesium and aluminum alloys offer an opportunity to mitigate the Balance Problem caused by these changes in the REE market. This is illustrated for REEs that can be recycled from fluorescent-lamp phosphor waste, CRT phosphors, and NiMH batteries. At present, five REEs (Nd, Eu, Tb, Dy, and Y) are being considered as very critical by Europe, the United States, and Japan, but we forecast that in the medium term, only neodymium will remain a critical REE. This paper discusses the relationship between criticality and the Balance Problem and shows how this relationship influences the market for specific REEs.

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Field enhancement in superconducting solenoids by holmium flux concentrators

Cited by 14 publications

References 1 publication

Compact Rare-Earth Superconducting Cyclotron

Compact Rare-Earth Superconducting Cyclotron

A miniature adiabatic demagnetization refrigerator with a magnetoresistive heat switch

Rare Earths and the Balance Problem: How to Deal with Changing Markets?

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