High-Magnetic-Field Research and Facilities [Final Report] (1979) / Chapter Skim
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HIGH-MAGNETIC-FIELD FACILITIES AND USERS
HIGH-MAGNETIC-FIELD FACILITIES AND USERS
Pages 72-93
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From page 72... ...
are being, or soon will be, produced by hybrid resistive-superconducting magnet systems, located necessarily at facilities with large power supplies for running the resistive magnets. For fields above 30 T, some type of transient operation, quasi-static or short72
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From page 73... ...
CONCLUSIONS The United States still leads the world in the number of large resistive magnet facilities, maximum field capability, number of magnet stations, and use of these facilities; but the development of facilities and their use in Europe have been increasing rapidly in the past few years. Recently, the increased demand for magnet time in both the United States and Europe has been for the highest available fields.
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From page 74... ...
be in place. CURRENT STATUS OF HIGH-MAGNETIC-FIELD FACILITIES Steady-State Field Facilities-Resistive Magnet Systems As we have mentioned, most of the high-magnetic-field facilities currently in operation in the world employ resistive magnets, and most of these are of the Bitter type and are water cooled.
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From page 75... ...
c cj 3 O J3 ^ "S £ «?
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From page 76... ...
der Technishen Universitat Braunschweig eg C.E.A., Saclay Clarendon Lab., Oxford International Laboratory for Magnetic Fields and Low Temperature, Wroclaw Kurchatov Atomic Energy Institute, Moscow 1 1 Installation h 2 "3 b o 4)
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From page 77... ...
. The cost of electrical power constitutes a relatively small fraction of the total cost at present, with salaries and overhead of support personnel making up the largest fraction.
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From page 78... ...
Recent developments in Europe are particularly interesting. Although the Clarendon Laboratory has had a resistive magnet facility for more than 30 years, the rest of the facilities are recent; for example, the joint French-German facility in Grenoble, the Braunschweig facility, and the Nijmegen facility have all been commissioned since 1971.
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From page 79... ...
provided to visitors. Steady-Field Facilities-Superconducting Magnet Systems Compared with that of resistive magnets, high-field superconducting magnet technology is relatively immature and has improved markedly in the past ten years.
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From page 81... ...
c "s OB « O o bJ rn Tokyo University Vac. Metallurgical Co" Japanese National Rei for Metal, Tsukuba Lebedev Physical Inst Electronics Institute, University of Wiirzbui Clarendon Laboratorj University of Sao Pau International Laborat Magnetic Fields and Kyushu University £ B Wroclaw o o pj 3 >> "o .| a c 60 o cd & H s5 \\ 13 « c "° "O i e S 0 B ^ o.
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From page 82... ...
A single superconducting magnet is not a facility and is not cost effective in this context. However, individual high-field superconducting magnets can be exceedingly effective and useful when dedicated to specific experiments if the capital and operating costs can be justified.
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From page 83... ...
Thus the capital costs of the resistive magnet facility are about a factor of 2 greater than for the superconducting facility. Operating costs are estimated for the resistive magnet facility from the actual total costs of the NRL facility, including salaries and overhead, maintenance, and the like, for 75 percent use of the total number of available 5-h experimental periods of $ 1500/period.
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From page 84... ...
In transient fields, on the other hand, particularly for the shorter time scales, measurement techniques are not so well developed; signal to noise is a much greater problem, and equilibrium conditions are not generally established. In addition, steady fields are easily used by inexperienced researchers, whereas the problems just cited for transient fields require a much more detailed knowledge of the technology and measurement techniques.
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From page 85... ...
Destruction of the coil and/or sample is a serious drawback to these approaches. However, in the past there has been significant effort devoted to production of ultrahigh magnetic fields by these techniques, and recently there has been renewed interest because of possible applications in controlled fusion research and compact, electrical power-source development.
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From page 86... ...
u 0 "J 0 0 2 1 u ration iif o o u o 3 i« CO
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From page 87... ...
FACILITY PLANS AND POSSIBILITIES Current Plans-Steady-State Fields As far as we can determine, no plans exist at present for extending the maximum fields produced by resistive magnets beyond those now obtainable at NML. However, construction of hybrid systems is planned or already in progress at all of the large resistive magnet facilities in the world that do not have such systems.
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From page 88... ...
These facilities can be developed most cost effectively at locations where resistive magnets and their power supplies already exist. In the near term, that is, from 2 to 5 years, 30 T will be available at the NML and, with a modest additional investment in a higherfield superconducting booster coil, this capability could be extended to 35 T with the present power supplies.
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From page 89... ...
Most of the increased scientific interest is in the highest available magnetic fields. The discussion that follows is based largely on information about and experience with the large resistive magnet facilities (most of which relates to NML)
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From page 90... ...
are located in the northeast part of the United States. It is useful to examine the geographic distribution of the outside visitors to the NML (including long-term visitors and some from abroad, though a small number of these visitors do not use the resistive magnets)
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From page 91... ...
Application and Screening Procedures Scientists who might be interested should be informed of the existence of high-magnetic-field facilities and of the details of fields provided and additional available facilities. Potential users can learn about high-field facilities in several ways: from journals that publish work conducted at an institution or that feature news stories (for example, Physics Today)
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From page 92... ...
Auxiliary Equipment and Facilities All the large resistive magnet facilities provide additional technical support, instrumentation, experimental equipment, and, in some cases, additional extensive facilities. We are concerned here with possible improvements in such facilities and the need for specific additional equipment and facilities.
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From page 93... ...
In addition to the routine equipment and consumable materials (cryogenic fluids, for example) that are generally provided by high-field facilities, the availability of certain specialized equipment that is either too sensitive or too large to be transported easily would make high-field facilities more generally useful and might attract scientists who, for reasons of logistics and equipment problems, have had to limit their use to the lower fields provided by superconducting magnets.
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