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calculations and other design considerations in the construction of high-field superconductive magnets; improvements in the stability of niobium-tin by plating with a high-conductivity metal and the electromagnetic performance of niobiumtin-vapour deposited ribbon up to 200 kilograms. The Corporation's "Vapodep" niobium tin superconductive ribbon is now commercially availal~le. ISO metric screw threads and fasteners G K N Bolts and Nuts Ltd have announced their stock range of bolts which conform completely to the ISO recommendations not only dimensionally but including the 1SO material property grades. A 9-page booklet is available giving complete specifications and conversion tables for Grade 8.8 high tensile bolts, screws and suitable nuts. Much interest has been shown, throughout the UK, in aspects of changeover to the metric system but little practical action has resulted. It must be noted that it is not possible to metricate by ordering the exact metric equivalent of a commonly used size in the inch system. This is because metric countries use nominal sizes which are round figures in millimetres, just as simple fractions of an inch are nominal sizes in the inch system. This means that the entire engineering drawing must be checked for stress and clearance considerations before the changeover is effected. The stock range has been limited to Grade 8.8 high tensile bolts and screws because these are fully adequate for most purposes and can be used in place of the lower strength black bolts as well as substitutes for high tensile bolts with Whitworth BSF or unified threads. The company offer to manufacture any specific size required, provided sufficient quantity is demanded. Ultrahigh Vacuum Furnaces A recent 18-page brochure containing general specifications for ultrahigh vacuum furnaces is available from the Vacuum Division of Varian Associates. Specifications and operating principles are described. Various performance curves, schematic diagrams and illustrations of component parts are also provided. Infrared ratio pyrometer A leaflet issued by Atomic Power Constructions Ltd, Hounslow, Middlesex, describes the recently developed infrared ratio pyrometer incorporating a design of radiation analyzer for which a patent is pending. This instrument combines the facility for remote and accurate surface temperature measurement in the range 250--1000°C with an ability to focus down to a target area of one square millimeter. It consists of a separate sensing head and computer indicator unit both of which are portable and may be operated from ac mains or internal rechargeable batteries. The temperature of static or moving materials may be measured independent of aperture and of intervening gases (provided there is no absorption at the two operational wavebands). The sensing head operates in
any position and in ambient temperatures up to 45°C. The reflex focusing system ensures accurate sighting and linear change of target size with distance. Birvae News A recent issue of Bir-Vac News (vol 4 no 1, 1967) describes their Sales and Technical Conference which took place in January. This was the first of its kind and included discussions on the design of high vacuum equipment which may be used both in the laboratory and on a production scale process. Synopses of the following lectures are given: Optical thin films, by P Clapham (National Physical Laboratory); High vacuum equipment in relation to the production of thin film electronic circuits, by J Maddison (Plessey Company Ltd); High vacuum for metallurgical research, by J Hains (Rolls-Royce Ltd, Aero Engine Division); Applications of high vacuum techniques to modern industry, by P R Hazel (Roils Royce) and Research in the United Kingdom on vacuum deposited thin films, by J R Balmer (Royal Radar Establishment). Notice is also given of data sheets now available describing a new electron gun, high vacuum evaporation units, a high vacuum induction heated furnace and a capsule type vacuum switch.
Thin Solid Films During 1967, Elsevier Publishing Company are to commence publication of a new bimonthly journal entitled Thin Solid Films, covering all aspects of the science and technology of film structures from atomic dimensions up to single or multilayers several tens of microns thick. Papers will be published in English, French or German and it is hoped that English summaries will be available for all papers. It is intended that the journal will deal with the following main topics: substrates; deposition techniques; structural properties; physical properties; physico-chemical properties and applications. All contributed papers will be refereed by workers drawn from a panel of acknowledged international experts each specializing in one or more aspects of thin film science and technology. Subscription orders and details of manuscript preparation are available from Elsevier Publishing Company, PO Box 211, Amsterdam, The Netherlands.
Commercial
news
West German order for Ferranti A £250,000 order for ceramic magnet chambers has been received by Ferranti Ltd from Deutsches Elektronen Synchrotron (DESY), the High Energy Physics Laboratory utilised by German Universities and founded by the German Federal Government and the Hamburg State Authority. The order was obtained in the face of strong American competition. The magnet chambers are for use on the 6 GeV electron synchrotron operated by DESY, one of the two such machines at
present in use in the Western world, the other being in the USA at Cambridge Massachusetts. A third has reached an advanced stage of construction at Daresbury, Cheshire, in England, and a fourth is contemplated at Cornell University in the USA. In the electron synchrotron a beam of electrons having an initial energy of 40 MeV is injected into a hollow ring in the horizontal plane. The ring has a diameter of 91 metres (100 yds) and a cross-sectional diameter of 15.2 cm (6 inches). Forty eight external magnets positioned around the circumference of the ring produce a field which causes the beam to follow a circular path through accelerating cavities. The electrons are speeded up in these cavities until, after a considerable number of orbits, the required energy level of 4 to 6 GeV is reached. In order to prevent the electron beam from scattering, the ring is constructed as a complete vacuum system. Each magnet is approximately 4.3 metres (14 It) long and, between the jaws, the ring is compressed into an elliptic cross-section--the magnet chambers. These chambers must be constructed of a non-metallic material since the magnetic field varies and arrangements must also be made to avoid any accumulated electrical charge. Organic resins have proved unsatisfactory and after extensive research a 97 per cent alumina ceramic, type UL300 was selected for the project. The ceramic is manufactured by Wade (Ireland) Ltd, in Ulster, Northern Ireland. Since single-piece construction in ceramic is not possible, a number of short sections are connected by robust vacuum tight joints. Each chamber is checked after installation with a helium mass-spectrometer leak detector. In the production of the magnet chambers over 305 metres (1000 ft) of elliptic alumina ceramic tube will be used, to which will be attached 2,000 cupro-nickei rings. The assembly of the individual sections will involve over 2,000 brazed ceramic-to-metal joints, and 1,000 welded joints. The total length of vacuum-tight ceramic-to-metal or metal-to-metal joint is over 1.6 kilometres (1 mile), and for electrical discharge purposes over 125 square metres (150 square yards) of metallizing will be deposited on the inner surfaces of the ceramic tube. The chambers must also fit very accurately between the magnet jaws. This necessitates the angular dimensions being measured in minutes and seconds of arc to maintain the required accuracy over the 4.8 metres (16 ft) length of the chamber. The magnet chambers are being manufactured at the Wythenshawe, Manchester, factory of Ferranti Ltd. The first prototype has already been delivered and production models are in an advanced state of construction. The chambers will enable DESY to increase the synchrotron beam current above the level at present possible and to reach the final design energy of 7.5 GeV. Large vacuum-insulated cryogenic vessel The photograph shows one of the two
287
calculations and other design considerations in the construction of high-field superconductive magnets; improvements in the stability of niobium-tin by plating with a high-conductivity metal and the electromagnetic performance of niobiumtin-vapour deposited ribbon up to 200 kilograms. The Corporation's "Vapodep" niobium tin superconductive ribbon is now commercially availal~le. ISO metric screw threads and fasteners G K N Bolts and Nuts Ltd have announced their stock range of bolts which conform completely to the ISO recommendations not only dimensionally but including the 1SO material property grades. A 9-page booklet is available giving complete specifications and conversion tables for Grade 8.8 high tensile bolts, screws and suitable nuts. Much interest has been shown, throughout the UK, in aspects of changeover to the metric system but little practical action has resulted. It must be noted that it is not possible to metricate by ordering the exact metric equivalent of a commonly used size in the inch system. This is because metric countries use nominal sizes which are round figures in millimetres, just as simple fractions of an inch are nominal sizes in the inch system. This means that the entire engineering drawing must be checked for stress and clearance considerations before the changeover is effected. The stock range has been limited to Grade 8.8 high tensile bolts and screws because these are fully adequate for most purposes and can be used in place of the lower strength black bolts as well as substitutes for high tensile bolts with Whitworth BSF or unified threads. The company offer to manufacture any specific size required, provided sufficient quantity is demanded. Ultrahigh Vacuum Furnaces A recent 18-page brochure containing general specifications for ultrahigh vacuum furnaces is available from the Vacuum Division of Varian Associates. Specifications and operating principles are described. Various performance curves, schematic diagrams and illustrations of component parts are also provided. Infrared ratio pyrometer A leaflet issued by Atomic Power Constructions Ltd, Hounslow, Middlesex, describes the recently developed infrared ratio pyrometer incorporating a design of radiation analyzer for which a patent is pending. This instrument combines the facility for remote and accurate surface temperature measurement in the range 250--1000°C with an ability to focus down to a target area of one square millimeter. It consists of a separate sensing head and computer indicator unit both of which are portable and may be operated from ac mains or internal rechargeable batteries. The temperature of static or moving materials may be measured independent of aperture and of intervening gases (provided there is no absorption at the two operational wavebands). The sensing head operates in
any position and in ambient temperatures up to 45°C. The reflex focusing system ensures accurate sighting and linear change of target size with distance. Birvae News A recent issue of Bir-Vac News (vol 4 no 1, 1967) describes their Sales and Technical Conference which took place in January. This was the first of its kind and included discussions on the design of high vacuum equipment which may be used both in the laboratory and on a production scale process. Synopses of the following lectures are given: Optical thin films, by P Clapham (National Physical Laboratory); High vacuum equipment in relation to the production of thin film electronic circuits, by J Maddison (Plessey Company Ltd); High vacuum for metallurgical research, by J Hains (Rolls-Royce Ltd, Aero Engine Division); Applications of high vacuum techniques to modern industry, by P R Hazel (Roils Royce) and Research in the United Kingdom on vacuum deposited thin films, by J R Balmer (Royal Radar Establishment). Notice is also given of data sheets now available describing a new electron gun, high vacuum evaporation units, a high vacuum induction heated furnace and a capsule type vacuum switch.
Thin Solid Films During 1967, Elsevier Publishing Company are to commence publication of a new bimonthly journal entitled Thin Solid Films, covering all aspects of the science and technology of film structures from atomic dimensions up to single or multilayers several tens of microns thick. Papers will be published in English, French or German and it is hoped that English summaries will be available for all papers. It is intended that the journal will deal with the following main topics: substrates; deposition techniques; structural properties; physical properties; physico-chemical properties and applications. All contributed papers will be refereed by workers drawn from a panel of acknowledged international experts each specializing in one or more aspects of thin film science and technology. Subscription orders and details of manuscript preparation are available from Elsevier Publishing Company, PO Box 211, Amsterdam, The Netherlands.
Commercial
news
West German order for Ferranti A £250,000 order for ceramic magnet chambers has been received by Ferranti Ltd from Deutsches Elektronen Synchrotron (DESY), the High Energy Physics Laboratory utilised by German Universities and founded by the German Federal Government and the Hamburg State Authority. The order was obtained in the face of strong American competition. The magnet chambers are for use on the 6 GeV electron synchrotron operated by DESY, one of the two such machines at
present in use in the Western world, the other being in the USA at Cambridge Massachusetts. A third has reached an advanced stage of construction at Daresbury, Cheshire, in England, and a fourth is contemplated at Cornell University in the USA. In the electron synchrotron a beam of electrons having an initial energy of 40 MeV is injected into a hollow ring in the horizontal plane. The ring has a diameter of 91 metres (100 yds) and a cross-sectional diameter of 15.2 cm (6 inches). Forty eight external magnets positioned around the circumference of the ring produce a field which causes the beam to follow a circular path through accelerating cavities. The electrons are speeded up in these cavities until, after a considerable number of orbits, the required energy level of 4 to 6 GeV is reached. In order to prevent the electron beam from scattering, the ring is constructed as a complete vacuum system. Each magnet is approximately 4.3 metres (14 It) long and, between the jaws, the ring is compressed into an elliptic cross-section--the magnet chambers. These chambers must be constructed of a non-metallic material since the magnetic field varies and arrangements must also be made to avoid any accumulated electrical charge. Organic resins have proved unsatisfactory and after extensive research a 97 per cent alumina ceramic, type UL300 was selected for the project. The ceramic is manufactured by Wade (Ireland) Ltd, in Ulster, Northern Ireland. Since single-piece construction in ceramic is not possible, a number of short sections are connected by robust vacuum tight joints. Each chamber is checked after installation with a helium mass-spectrometer leak detector. In the production of the magnet chambers over 305 metres (1000 ft) of elliptic alumina ceramic tube will be used, to which will be attached 2,000 cupro-nickei rings. The assembly of the individual sections will involve over 2,000 brazed ceramic-to-metal joints, and 1,000 welded joints. The total length of vacuum-tight ceramic-to-metal or metal-to-metal joint is over 1.6 kilometres (1 mile), and for electrical discharge purposes over 125 square metres (150 square yards) of metallizing will be deposited on the inner surfaces of the ceramic tube. The chambers must also fit very accurately between the magnet jaws. This necessitates the angular dimensions being measured in minutes and seconds of arc to maintain the required accuracy over the 4.8 metres (16 ft) length of the chamber. The magnet chambers are being manufactured at the Wythenshawe, Manchester, factory of Ferranti Ltd. The first prototype has already been delivered and production models are in an advanced state of construction. The chambers will enable DESY to increase the synchrotron beam current above the level at present possible and to reach the final design energy of 7.5 GeV. Large vacuum-insulated cryogenic vessel The photograph shows one of the two
287