- Email: [email protected]
624. Method of preparing a lanthanum hexaboride cathode
Classified
abstracts
619-628
liquid nitrogen trap at pressure of IO-’ torr. In the diffusion pump, silicone oil DC-704 was used. During the investigation of a sample cut from a silicon monocrystal, a change of contrast is visible after 10 minutes of observation. This time is more than 2 hours, if the liquid nitrogen trap is used. The polymerisation region is almost the same as the observation area, with a diameter of about I mm. The film grown in such conditions has no rough boundary. The dependence of polymerisation on electrostatic field was observed by using an immersion objective with a high radial anisotropy. The film is also visible in white reflected light after taking the sample out of the mirrer electron microscope. Its thickness was about 100 A, measured by means of a light interferometer. It is found that the silicone polymer layer surface is charged positively with respect to the silicon crystal substrate. (Poland) T Warminski, Phys S/at So/ (a), 3 (3), Nov 1970, K 159-K 161. 30 619. On the elastoresistance effect in evaporated tellurium films. (Germany) The change in electrical resistance of thin evaporated films of tellurium due to application of an elastic strain is measured. The films were prepared by thermal evaporation of purified polycrystalline tellurium from a quartz crucible onto glass substrates in a bell jar evacuated by an ion pump and a titanium sublimation pump. The pressure was always better than I x IO ’ torr at the beginning of the evaporation. Gold contacts were deposited by evaporation on glass substrates. The resistance-strain data were obtained by using a constant strength cantilever beam. The electrical resistance-strain coefficients of tellurium films have been measured. A relaxation phenomenon with a time constant greater than 10 minutes is observed. It is found that a deposit of silver on tellurium films decreases the time constant to 1 minute and less. (France) M Granveaud and Y Petroff, Ph.~x Stat Sol (a), 3 (3). Not, 1970, 629-638.
31. EVACUATION
AND SEALING
31 620. Packaging for the storage of electrical vacuum apparatus in vacua. (USSR) An improved form of packaging for the storage of electrical vacuum apparatus in vacua is proposed; basically it comprises a doublelayered container with one layer of glass and another of metal. This arrangement offers protection from the leakage of atmospheric gases and corrosive media. The electrical vacuum apparatus in the container rests on springs to protect it from mechanical shock, these being placed in position before the container is evacuated and sealed. The vacuum between the container walls and the stored apparatus also insulates the latter thermally, eliminating the thermal shock which damages apparatus stored under conventional conditions. The storage arrangement may furthermore provide useful information as to the long-term vacuum-tightness of electronic valves. A N Kamyshnyi et al, USSR PatefIt No 269,333, appl 3 Ju/~b 1967. publd I6 Ju[v 1970. 31 :33 621. Apparatus for assembling the fittings of receiving and amplifying valves. (USSR) An improved device for assembling the fittings of receiving and amplifying valves is described; this is distinguished by the fact that the assembly system is arranged in a single straight line, with a number of equally-spaced sockets, communicating with a multipleposition drum which controls guides for the individual centring of the various elements and devices for fixing the units in position after assembly. This arrangement eases work and eliminates human error in the centring of individual parts. V M Provalin et al, No 252,485, appl6 June 1968, prrblcl9 March 1970. 31 622. Method of cleaning the parts of metalloceramic radio valves. (USSR) An improved device which facilitates the cleaning of metalloceramic parts in radio valves during the evacuation of these prior to final soldering and sealing is described. By applying a voltage of 7003500 V to the parts in question, the latter are subjected to an intensive bombardment by ions arising from decomposition products of the oxide cathode coating. Normal heat treatment and sealing-off follows immediately after the ion bombardment. The arrangement of the electrodes and current leads in the improved cleaning system 294
is such as to facilitate automation of the whole process the number of individual operations to a minimum. A P Krasnov, USSR Patent. No 263.751. appl 10 Jo/w 24 Jme 1970.
and
reduce
1968. prrbld
31 623. A production valve panel. (USSR) An improved type of valve panel specially designed to accommodate large number of valves with very small distances between them is described. In order to simplify the contact system, radially-distributed sprung rods are employed to make contact with the valve pins. In this way the insertion of valves in the panel becomes an easy and smooth operation with a minimum danger of damage; in the same way the removal of valves can be readily effected without harm to the system as a whole. N N Kalashnikov et al, USSR Patent No 264,496, uppl25 Mu!, 1966. prrhltl 19 Jww 1970. 31:33 624. Method of preparing a lanthanum hexahoride cathode. (USSR) Disadvantages of existing methods of making lanthanum hexaboridc cathodes by cold extrusion. with subsequent baking and the incorporation of activating additives, are discussed. The high baking temperature and chemical interaction with the additives tend to make the cathode structure brittle. The use of powdered nickel (IL5 per cent) as an additional activating additive, however. results in the formation of a nickel boride of low melting point: this reduces the cathode sintering temperature by 2OO’C. and the density of the mouldings is correspondingly increased by nearly 10 per cent. During the sintering process the nickel compounds tend to evaporate, and this improves the mechanical properties of the remaining cathode material, The nickel also reduces the work function of the lanthanum hexaboride to 2.6 eV at 1600’ C. G M Kuznetsova and G A Kudintseva, USSR Pu/eur NIJ 256,880. U/)/I/ 24 Dee 1968, p~rhtcl 24 July 1970. 31 :33 625. Method of installing vacuum-tight electrical leads in an insulator. (USSR) An improvement to the existing method of introducing electric leads into an insulator (by forcing the heated lead through a previouslydrilled aperture) is described. Thus in the new technique a hole much smaller than the lead is first drilled and, after being sharpened and heated, the lead is itself used as a “drill” by rotating it at 300 500 rpm and forcing it into the hole, the motion being abruptly arrested on reaching the desired position. Such installations arc extremely vacuum-tight. F G Unger, USSR Paimt, No 272.442. appl 3 Nov 1967, ~~hlcl I SL’/)( 1960. 31 142 626. Investigation of the heat exchange in diathermal bodies of electrovacuum glass during heating by infrared radiation. (USSR) A theoretical analysis of glass heating by infrared radiation is presented. The temperature field distribution in the glass, heating rate, and the effects on the glass properties are determined. 0 G Smirnov et al, Elektrorz Tekh Tekhd OrFuniz Proizv, 2, 1970. 43-56 (ifi Rmsia,l). 31 :45 627. Solder for soldering electrical vacuum apparatus. (USSR) An improved type of solder for soldering parts of electrical vacuum apparatus is described; it contains germanium l-5, nickel l-3, and copper 92-98 per cent. The melting point is 1040-107O’C and the soldering temperature 1080°C. This solder wets nickel, iron, molybdenum, and tungsten without undergoing appreciable chemical interactions with these at the soldering temperature: it is accordingly suitable for joining very fine components. The vapour pressure of the solder is IO-’ torr at 8OO”C, it may easily be worked in the cold state, giving foils and wires of a wide range of dimensions, and yields joints of a fairly high mechanical strength. M N Tutorskaya et al, USSR Patent, No 264, 139, appl 2 DCY 196X. prrbld 4 Ju/w 1970. 31
628. Theorv of calculation for the thermal distribution in the cathode assembly oi a travelling wave tube. (USSR) A system of equations is prescntcd which forms the basis for a detailed calculation of the thermal distribution in the cathode-heater assembly of a travelling wave tube. These equations give a qualitative estimate
abstracts
619-628
liquid nitrogen trap at pressure of IO-’ torr. In the diffusion pump, silicone oil DC-704 was used. During the investigation of a sample cut from a silicon monocrystal, a change of contrast is visible after 10 minutes of observation. This time is more than 2 hours, if the liquid nitrogen trap is used. The polymerisation region is almost the same as the observation area, with a diameter of about I mm. The film grown in such conditions has no rough boundary. The dependence of polymerisation on electrostatic field was observed by using an immersion objective with a high radial anisotropy. The film is also visible in white reflected light after taking the sample out of the mirrer electron microscope. Its thickness was about 100 A, measured by means of a light interferometer. It is found that the silicone polymer layer surface is charged positively with respect to the silicon crystal substrate. (Poland) T Warminski, Phys S/at So/ (a), 3 (3), Nov 1970, K 159-K 161. 30 619. On the elastoresistance effect in evaporated tellurium films. (Germany) The change in electrical resistance of thin evaporated films of tellurium due to application of an elastic strain is measured. The films were prepared by thermal evaporation of purified polycrystalline tellurium from a quartz crucible onto glass substrates in a bell jar evacuated by an ion pump and a titanium sublimation pump. The pressure was always better than I x IO ’ torr at the beginning of the evaporation. Gold contacts were deposited by evaporation on glass substrates. The resistance-strain data were obtained by using a constant strength cantilever beam. The electrical resistance-strain coefficients of tellurium films have been measured. A relaxation phenomenon with a time constant greater than 10 minutes is observed. It is found that a deposit of silver on tellurium films decreases the time constant to 1 minute and less. (France) M Granveaud and Y Petroff, Ph.~x Stat Sol (a), 3 (3). Not, 1970, 629-638.
31. EVACUATION
AND SEALING
31 620. Packaging for the storage of electrical vacuum apparatus in vacua. (USSR) An improved form of packaging for the storage of electrical vacuum apparatus in vacua is proposed; basically it comprises a doublelayered container with one layer of glass and another of metal. This arrangement offers protection from the leakage of atmospheric gases and corrosive media. The electrical vacuum apparatus in the container rests on springs to protect it from mechanical shock, these being placed in position before the container is evacuated and sealed. The vacuum between the container walls and the stored apparatus also insulates the latter thermally, eliminating the thermal shock which damages apparatus stored under conventional conditions. The storage arrangement may furthermore provide useful information as to the long-term vacuum-tightness of electronic valves. A N Kamyshnyi et al, USSR PatefIt No 269,333, appl 3 Ju/~b 1967. publd I6 Ju[v 1970. 31 :33 621. Apparatus for assembling the fittings of receiving and amplifying valves. (USSR) An improved device for assembling the fittings of receiving and amplifying valves is described; this is distinguished by the fact that the assembly system is arranged in a single straight line, with a number of equally-spaced sockets, communicating with a multipleposition drum which controls guides for the individual centring of the various elements and devices for fixing the units in position after assembly. This arrangement eases work and eliminates human error in the centring of individual parts. V M Provalin et al, No 252,485, appl6 June 1968, prrblcl9 March 1970. 31 622. Method of cleaning the parts of metalloceramic radio valves. (USSR) An improved device which facilitates the cleaning of metalloceramic parts in radio valves during the evacuation of these prior to final soldering and sealing is described. By applying a voltage of 7003500 V to the parts in question, the latter are subjected to an intensive bombardment by ions arising from decomposition products of the oxide cathode coating. Normal heat treatment and sealing-off follows immediately after the ion bombardment. The arrangement of the electrodes and current leads in the improved cleaning system 294
is such as to facilitate automation of the whole process the number of individual operations to a minimum. A P Krasnov, USSR Patent. No 263.751. appl 10 Jo/w 24 Jme 1970.
and
reduce
1968. prrbld
31 623. A production valve panel. (USSR) An improved type of valve panel specially designed to accommodate large number of valves with very small distances between them is described. In order to simplify the contact system, radially-distributed sprung rods are employed to make contact with the valve pins. In this way the insertion of valves in the panel becomes an easy and smooth operation with a minimum danger of damage; in the same way the removal of valves can be readily effected without harm to the system as a whole. N N Kalashnikov et al, USSR Patent No 264,496, uppl25 Mu!, 1966. prrhltl 19 Jww 1970. 31:33 624. Method of preparing a lanthanum hexahoride cathode. (USSR) Disadvantages of existing methods of making lanthanum hexaboridc cathodes by cold extrusion. with subsequent baking and the incorporation of activating additives, are discussed. The high baking temperature and chemical interaction with the additives tend to make the cathode structure brittle. The use of powdered nickel (IL5 per cent) as an additional activating additive, however. results in the formation of a nickel boride of low melting point: this reduces the cathode sintering temperature by 2OO’C. and the density of the mouldings is correspondingly increased by nearly 10 per cent. During the sintering process the nickel compounds tend to evaporate, and this improves the mechanical properties of the remaining cathode material, The nickel also reduces the work function of the lanthanum hexaboride to 2.6 eV at 1600’ C. G M Kuznetsova and G A Kudintseva, USSR Pu/eur NIJ 256,880. U/)/I/ 24 Dee 1968, p~rhtcl 24 July 1970. 31 :33 625. Method of installing vacuum-tight electrical leads in an insulator. (USSR) An improvement to the existing method of introducing electric leads into an insulator (by forcing the heated lead through a previouslydrilled aperture) is described. Thus in the new technique a hole much smaller than the lead is first drilled and, after being sharpened and heated, the lead is itself used as a “drill” by rotating it at 300 500 rpm and forcing it into the hole, the motion being abruptly arrested on reaching the desired position. Such installations arc extremely vacuum-tight. F G Unger, USSR Paimt, No 272.442. appl 3 Nov 1967, ~~hlcl I SL’/)( 1960. 31 142 626. Investigation of the heat exchange in diathermal bodies of electrovacuum glass during heating by infrared radiation. (USSR) A theoretical analysis of glass heating by infrared radiation is presented. The temperature field distribution in the glass, heating rate, and the effects on the glass properties are determined. 0 G Smirnov et al, Elektrorz Tekh Tekhd OrFuniz Proizv, 2, 1970. 43-56 (ifi Rmsia,l). 31 :45 627. Solder for soldering electrical vacuum apparatus. (USSR) An improved type of solder for soldering parts of electrical vacuum apparatus is described; it contains germanium l-5, nickel l-3, and copper 92-98 per cent. The melting point is 1040-107O’C and the soldering temperature 1080°C. This solder wets nickel, iron, molybdenum, and tungsten without undergoing appreciable chemical interactions with these at the soldering temperature: it is accordingly suitable for joining very fine components. The vapour pressure of the solder is IO-’ torr at 8OO”C, it may easily be worked in the cold state, giving foils and wires of a wide range of dimensions, and yields joints of a fairly high mechanical strength. M N Tutorskaya et al, USSR Patent, No 264, 139, appl 2 DCY 196X. prrbld 4 Ju/w 1970. 31
628. Theorv of calculation for the thermal distribution in the cathode assembly oi a travelling wave tube. (USSR) A system of equations is prescntcd which forms the basis for a detailed calculation of the thermal distribution in the cathode-heater assembly of a travelling wave tube. These equations give a qualitative estimate