Classified abstracts
1863-1874
the metal layer at the point of breakdown with a current surge. (Author) Union Carbide Corp, Brif Patent 1,075,094, Patent Abstr, 7 (31) (part 6), 4th Aug 1967, 1. 31. EVACUATION AND SEALING 31 : 18 Porosity effects in the ionization of caesium on tungsten. See abstract number 1779. 31 : 18 Thermionic emitters consisting of BaO-UO, dispersed in a tungsten matrix. See abstract number 1791. 31 ~46 1863. Cryostat for magneto-optical investigations. (USSR) A design of a laboratory cryostat for investigations at liquid helium temperatures is described. A quartz window is sealed to metal walls by epoxy resin containing 66 per cent of ED-6 epoxy, 6 per cent of hexamethylenediamide and 28 per cent of Al powder. This resin is vacuum-tight and also usable for quick temperature changes from 300 to 4°K. V N Pavlov and V V Eremenko, Pribory Tekh Eksper, 12 (3), May-June 1967, 208-210 (in Russian). 31 1864. Physical chemistry of cleaning. (USA) The effects of contaminants on the properties of materials important to electronic devices and to related vacuum processes are discussed. Modern methods of testing and maintaining cleanliness are described. G L Krieger et al, Rep SC-TM-66-428 (Sandia Carp, Albuquerque, New Mexico). 31 1865. A glass/metal liquid helium Dewar. (USA) Helium Dewars are usually made either of glass or of metal, each with its merits and drawbacks. The Dewar described retains the merits of both types Dewars, the inside being made of glass and the outside of metal. The two parts are connected by an O-ring seal. C Bickart and C R Viswanathan, Cryogenic Technol, 3 (3), 1967,96-98. 31 1866. Electron discharge device having a vacuum sealing member and mechanical support means between the tube main body and the collector. (USA) This high frequency discharge device includes a beam forming and projecting means coupled at the upstream end and a metal beam collector member coupled to the body at the downstream end. It has an annular dielectric insulating member, vacuum sealed between the tube main body and metal beam collector, The tube forms a vacuum envelope in conjunction with the metal collector member, beam forming and projecting means. It is mechanically supported but insulated from the tube. Varian Associates, US Patent 3,336,491, Official Gaz USPatent Office, 841 (3), 15th Aug 1967, 988. 31 1867. Cryostat. (Germany) This has thermal vacuum insulation for operation with liquid coolants, such as liquid nitrogen, has a coolant container, an outer jacket and athermal shield consisting of two coaxial walls forming a vacuum tight space between container and jacket, whereby the latter has a cover in which are provided openings for insertion of coolant, removal of vapour and other purposes. A vacuum-tight connection is provided in each case between the upper edges of the container and the inner wall and the upper edges of the jacket and the outer wall. The two walls have a vacuum tight seal to each other only at their lower edges and form a jacketing space which is open towards the vapour chamber in the container and in which an insert of low thermal conductivity and fixed to the cover is arranged coaxially, whereby the the opening for vapour removal lies between this insert and the outer wall. (Author) V E Keijlin, German Patent 1,242,898, Patent Abstr, 7 (30) part D, 2nd Aug 1967, 3. 32. NUCLEONICS
32 : 20 Mechanical design of the baseball coil and plasma-trapping chamber. See abstract number 1797. 32 : 21 Liquid helium cryopumps for a large plasma research machine. See abstract number 1807. 624
32 : 18 1868. Plasma sources of ions of high-melting point materials. (USSR) Recent methods of producing a beam of high-melting point material ions by means of a discharge in the material vapours are summarized and compared. Typical designs of ion sources for electromagnetic isotope separators are discussed. M D Gabovich, Pribory Tekh Eksper, 12 (3), May-June 1967, 5-19 (in Russian). 32 1869. Deflection of an accelerated beam to the internal target in a
strong-focusing Synchrotron. (USSR) Equations are derived to illustrate a method of achieving an azimuthally symmetric local orbit perturbation with respect to the target. This method can be used to deflect the beam from the vacuum chamber in accelerators which use laminated electromagnets, when the perturbation increases quickly enough. I A Shukeilo, Elec Instr High-Energy Phys, (Collection of Papers), No 1, Rep AEC-TR-6636, Dee 1966, l-5 (Israel Programme for Scientific
Translations
Ltd, Jerusalem).
32 1870. Ion-optical system computation for direct action accelerators
taking into account space charge. (USSR) General relations between beam parameters at the entrance and exit of the accelerator tube are derived, and a method of computing optimum beam input parameters is given. Shaping of the charged particle beam at the entrance of the accelerator tube by electrostatic focusing systems is discussed. V S Kuznetzov, Elec Instr, High-Energy Phys, (Collection of Papers), No 1, Rep AEC-TR-6636, Dee 1966, 66-77 (Israel Programme for Scientific
Translations
Ltd, Jerusalem). 32
1871. A high-current pulsed ion course.
(USSR) The ion source and measurement apparatus are described; experimental procedures and results are discussed. Emphasis in the description is placed on the selection system and the displacement of the plasma emission opening in the region of maximum intensity of the magnetic field. It was found that: (1) the cover plate-extracting electrode with grid selection system affords stable ion beams with currents up to 1.5 A ; (2) it is possible to obtain focused ion beams of 70 KeV; (3) further increase of the ion current is possible through increase of the size of the source and a corresponding increase of the operational parameters. The most promising means of obtaining both pulsed and continuous ion beams with a current considerably in excess of 1 A is by using multijet plasma sources which create a large, dense plasma surface in the selection region. M A Abroyan and V L Komarov, Elec Instr High-Energy Phys (Collection ofPapers), No 1, Rep AEC-TR-6636,97-109 (Israel Programme for Scientific
Translations
Ltd, Jerusalem). 32
: 33
1872. A high voltage trielectrode electron gun.
(USSR) The effect on beam focusing and other gun parameters of a cathode placed along the axis of an electron gun with Pierce optics, and a tri-electrode electron gun design based on the Pierce gun are discussed. A description is given of the tri-electrode gun, for pulsed operation at 80 kV with beam currents of up to 5A, in which it is possible to alter the beam current without affecting the angle of divergence and beam energy. The gun is completely demountable. K P Rybas and A T Ermolaev, Elec Znstr High-Energy Phys, (Collection of Papers), No 1, Rep AEC-TR-6636, Dee 1966, 110-l 17 (Israel Programme for Scientific
Translations
Ltd, Jerusalem).
32 1873. A high frequency ion source for direct action accelerators.
(USSR) An ion source design for electrostatic and neutron generators is described which provides compactness, simplicity and reliability of construction, low supply power and small gas discharge. The source was checked in a scale model of a 2 MeV electrostatic generator. L I Ivanova and A I Solnyshkov, Elec Znstr High-Energy Phys (Collection of Papers) No 1, 1966, Rep AEC-TR-6636, 118-122 (Israel Programme for Scientific Translations Ltd, Jerusalem). 32 1874. Vacuum chambers of strong-focusing synchrotrons.
(USSR) The requirements and designs for accelerator vacuum chambers are reviewed. The chamber material and thickness, the effects of pressure difference on inside and outside of walls, and the effects of particle bombardment are considered. Details are presented on chamber