- Email: [email protected]
739. 4 GeV electron synchrotron for the north of England
290
Classified Abstracts 729--741
31.
Evacuation and S e a l i n g
31 : 56 729. Ultra-low-noise travelling-wave tube with simple electron gun. (Great Britain) B. G. Bosch and K. B. Niclas, Proc. Inst. Radio Engrs, 50, March 1962, 324. 31 : 56 730. Moisture exclusion from encapsulation of long-life transistors. Great Britain. The surfaces of the semiconductor wafers used in transistors are damaged by adsorbed water ; failure to appreciate this was responsible for the disappointingly short life of early transistors. In current practice, they are hermetically sealed and filled with dry gas, usually in a metal can with glass/metal terminals. Transistors may be stored for long periods at temperatures as low as --55°C, and then rapidly put into operation at 150°C, and this must not cause excessive desorption of water vapour sorbed whilst at low temperature. To achieve this, the units are vacuum-furnaced at 150°C (for germanium) or 300°C (for silicon), and then handled up to the sealing-in process in glove boxes in a stream of very dry air, " very dry " being said to mean having a dew point not above --40°C, and preferably as low as --60°C. The aim is to ensure that the dew point of the residual atmosphere in the sealed unit shall be lower than the lowest anticipated storage or operating temperature. This is estimated to leave a maximum of 2/~g of water adsorbed on the glass and metal parts, and about 0.01/zg in the gas, To deal with water vapour desorbed in operation, or leaking in through the can and seal, molecular sieve is recommended, 10 mg properly activated will hold 120 mg of water at 150°C and can easily be accommodated inside the unit, It will also keep the unit " dry " for 60 y if the rate of inleakage of water is not more than 2.5 × 107 molecules/see. Leaks of this size can he detected by filling with radioactive krypton. In practice, only 1 per cent or 2 per cent of cans have larger leaks. R. I. B. Cooper, Proc. Inst. Radio Engrs, 50, Feb. 1962, 141-147. 31 : 56 731. Recent developments in space-charge-control tubes. U.S.A. A n u m b e r of important technological developments have taken place in recent years in the field of " conventional " (i.e. triode, etc.) valves, although these tend to have been overshadowed by the spectacular progress of semiconductor devices. The developments reviewed in this article include a new type of oxide cathode with a smooth surface, capable of allowing close electrode spacings, and filamentary cathodes having very short warm-up times to save stand-by power consumption in mobile communications equipment. There is also a range of new valves which will work from a 12-V h.t. supply, making them compatible with transistors. Among constructional improvements are the " Nivistor ", constructed with an external copper anode, and robust internal assembly (like a small transmitting valve), and many metal/ceramic envelope types. There is also mentioned a distributed amplifier tube, with the delay lines inside the envelope, and an electron multiplier valve capable of giving 5A peak output, with a mutual conductance of 600 mA/V. K. R. Spangenberg, Proc. Inst. Radio Engrs, 50, May 1962, 967-969. 31:56 732. Beam deflexion and photo devices. U.S.A. This article reviews the history, and the present position of television camera tubes, cathode-ray tubes, storage tubes, photo-cells, electron multipliers and image tubes. (Authors, modified) K. Schlesinger and E. G. Ramberg, Proc. Inst. Radio Engrs, 50, May 1962, 991-1005. 31 : 56
733. The development of gas discharge tubes. U.S.A. This article reviews the history of gas discharge tubes,
under the following headings : Ionization Tubes, Cold-cathode Discharge Tubes, Hot-cathode Discharge Tubes, Liquid Metal Arc Tubes and Plasma Tubes (these are microwave devices). (Author, modified) J. D. Cobine, Proc. Inst. Radio Engrs, 50, May 1962, 970-978. 31 "56 734. A history of the microwave tube art. (Great Britain) J. R. Pierce, Proc. Inst. Radio Engrs, 50, May 1962, 978-984. 31 : 56 735. Cathode-ray tube with internal printed coils for magnetic deflexion. (Great Britain) Anon., Brit. Commun. & Electron., 10, March 1963, 217. 31 : 56 736. Current European developments in microwave tubes. (Great Britain) A. H. W. Beck, Proc. Inst, Radio Engrs, 50, May 1962, 985-991.
32,
Nucleonics
32 737. Assembly and operation of a 300 KeV electrostatic neutron source. Italy. A 300 keV electrostatic ion accelerator for the production of fast neutrons is described. A special target assembly permits the a-particles from the T(d; n)4He reaction to be utilized for coincidence work and for monitoring. For the latter purpose a silicon junction detector is used. The results of different measurements of the neutron flux are given. (in English) (Authors) G. Bonazzola, et al., Nuovo Cimento, 23 Suppl. No. 1, (1962), 67. 32 738. Light chamber or gas-amplified scintillation chamber. Italy. A gas detector has been realized and developed using principles of the works of Charpak, Fukul and Miyamoto, Colli and others. The detector can furnish a luminous image of the track of an ionized particle, with isotropic properties within the chamber volume, in such a way as to retain the information on the direction, range and ionization density. Operation is based on the decay of excited states caused by secondary electrons obtained by Townsend local multiplication of the primary electrons along the track. The multiplicator is obtained through the application of a damped radio-frequency oscillation of electric field, which is given by a pulse generator triggered by a multiplier phototube that is sensitive to the primary scintillation. A typical photograph is shown of the tracks of a-particles obtained with such an instrument. The light intensity obtained up to now restricts the use of the observation of particles characterized by high ionization density. (in English) (Authors) C. Cavalleri, et al., Nuovo Cimento, 25, (1962), 1282. 32 739. 4 GeV electron synchrotron for the north of England. (Great Britain) Anon., Engineer, 214, 3 Aug. 1962, 203. 32 740. 50 MeV cyclotron for Harwell. (Great Britain) Anon., Engineer, 214, 24 Aug. 1962, 322.
Latest steps towards fusion power. 33.
32 : 58 : 18 See Abstr. No. 694.
General Physics and Electronics
33 741. Compatibility of metals and cryogenic liquids. (U.S.A.) J. L. Christian, et al., Metal Prog., 33 (4), April 1963, 100-103
Classified Abstracts 729--741
31.
Evacuation and S e a l i n g
31 : 56 729. Ultra-low-noise travelling-wave tube with simple electron gun. (Great Britain) B. G. Bosch and K. B. Niclas, Proc. Inst. Radio Engrs, 50, March 1962, 324. 31 : 56 730. Moisture exclusion from encapsulation of long-life transistors. Great Britain. The surfaces of the semiconductor wafers used in transistors are damaged by adsorbed water ; failure to appreciate this was responsible for the disappointingly short life of early transistors. In current practice, they are hermetically sealed and filled with dry gas, usually in a metal can with glass/metal terminals. Transistors may be stored for long periods at temperatures as low as --55°C, and then rapidly put into operation at 150°C, and this must not cause excessive desorption of water vapour sorbed whilst at low temperature. To achieve this, the units are vacuum-furnaced at 150°C (for germanium) or 300°C (for silicon), and then handled up to the sealing-in process in glove boxes in a stream of very dry air, " very dry " being said to mean having a dew point not above --40°C, and preferably as low as --60°C. The aim is to ensure that the dew point of the residual atmosphere in the sealed unit shall be lower than the lowest anticipated storage or operating temperature. This is estimated to leave a maximum of 2/~g of water adsorbed on the glass and metal parts, and about 0.01/zg in the gas, To deal with water vapour desorbed in operation, or leaking in through the can and seal, molecular sieve is recommended, 10 mg properly activated will hold 120 mg of water at 150°C and can easily be accommodated inside the unit, It will also keep the unit " dry " for 60 y if the rate of inleakage of water is not more than 2.5 × 107 molecules/see. Leaks of this size can he detected by filling with radioactive krypton. In practice, only 1 per cent or 2 per cent of cans have larger leaks. R. I. B. Cooper, Proc. Inst. Radio Engrs, 50, Feb. 1962, 141-147. 31 : 56 731. Recent developments in space-charge-control tubes. U.S.A. A n u m b e r of important technological developments have taken place in recent years in the field of " conventional " (i.e. triode, etc.) valves, although these tend to have been overshadowed by the spectacular progress of semiconductor devices. The developments reviewed in this article include a new type of oxide cathode with a smooth surface, capable of allowing close electrode spacings, and filamentary cathodes having very short warm-up times to save stand-by power consumption in mobile communications equipment. There is also a range of new valves which will work from a 12-V h.t. supply, making them compatible with transistors. Among constructional improvements are the " Nivistor ", constructed with an external copper anode, and robust internal assembly (like a small transmitting valve), and many metal/ceramic envelope types. There is also mentioned a distributed amplifier tube, with the delay lines inside the envelope, and an electron multiplier valve capable of giving 5A peak output, with a mutual conductance of 600 mA/V. K. R. Spangenberg, Proc. Inst. Radio Engrs, 50, May 1962, 967-969. 31:56 732. Beam deflexion and photo devices. U.S.A. This article reviews the history, and the present position of television camera tubes, cathode-ray tubes, storage tubes, photo-cells, electron multipliers and image tubes. (Authors, modified) K. Schlesinger and E. G. Ramberg, Proc. Inst. Radio Engrs, 50, May 1962, 991-1005. 31 : 56
733. The development of gas discharge tubes. U.S.A. This article reviews the history of gas discharge tubes,
under the following headings : Ionization Tubes, Cold-cathode Discharge Tubes, Hot-cathode Discharge Tubes, Liquid Metal Arc Tubes and Plasma Tubes (these are microwave devices). (Author, modified) J. D. Cobine, Proc. Inst. Radio Engrs, 50, May 1962, 970-978. 31 "56 734. A history of the microwave tube art. (Great Britain) J. R. Pierce, Proc. Inst. Radio Engrs, 50, May 1962, 978-984. 31 : 56 735. Cathode-ray tube with internal printed coils for magnetic deflexion. (Great Britain) Anon., Brit. Commun. & Electron., 10, March 1963, 217. 31 : 56 736. Current European developments in microwave tubes. (Great Britain) A. H. W. Beck, Proc. Inst, Radio Engrs, 50, May 1962, 985-991.
32,
Nucleonics
32 737. Assembly and operation of a 300 KeV electrostatic neutron source. Italy. A 300 keV electrostatic ion accelerator for the production of fast neutrons is described. A special target assembly permits the a-particles from the T(d; n)4He reaction to be utilized for coincidence work and for monitoring. For the latter purpose a silicon junction detector is used. The results of different measurements of the neutron flux are given. (in English) (Authors) G. Bonazzola, et al., Nuovo Cimento, 23 Suppl. No. 1, (1962), 67. 32 738. Light chamber or gas-amplified scintillation chamber. Italy. A gas detector has been realized and developed using principles of the works of Charpak, Fukul and Miyamoto, Colli and others. The detector can furnish a luminous image of the track of an ionized particle, with isotropic properties within the chamber volume, in such a way as to retain the information on the direction, range and ionization density. Operation is based on the decay of excited states caused by secondary electrons obtained by Townsend local multiplication of the primary electrons along the track. The multiplicator is obtained through the application of a damped radio-frequency oscillation of electric field, which is given by a pulse generator triggered by a multiplier phototube that is sensitive to the primary scintillation. A typical photograph is shown of the tracks of a-particles obtained with such an instrument. The light intensity obtained up to now restricts the use of the observation of particles characterized by high ionization density. (in English) (Authors) C. Cavalleri, et al., Nuovo Cimento, 25, (1962), 1282. 32 739. 4 GeV electron synchrotron for the north of England. (Great Britain) Anon., Engineer, 214, 3 Aug. 1962, 203. 32 740. 50 MeV cyclotron for Harwell. (Great Britain) Anon., Engineer, 214, 24 Aug. 1962, 322.
Latest steps towards fusion power. 33.
32 : 58 : 18 See Abstr. No. 694.
General Physics and Electronics
33 741. Compatibility of metals and cryogenic liquids. (U.S.A.) J. L. Christian, et al., Metal Prog., 33 (4), April 1963, 100-103