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265. Apparatus for the controlled deposition of optical film systems
298
Abstracts 263--271
Use of Zirconium Slntered Getters
16 21 See Abstr No 281
33
16 21 33 The Ceto Getter--its Chemical Structure and Hydrogen Gettermg Properties See Abstr No 282 16 47 36 20 System Design and the Choice of Materials for the " Nimrod " Vacuum System See Abstr No 368
18.
Gaseous Electronics
18 22 30 263. Cathothc Etclung m a Penning Cold Cathode Discharge Umted Kingdom An apparatus for cathodic etching using a Penning cold cathode discharge is described One of the twin cathodes is the specimen to be etched whilst the other is made of alummlum The cathodes are water cooled so that metals of either low melting point or low sputtering rate will not overheat during the cathodic etching The Penning system is used because the glow d~scharge can be maintained at a sufficiently low pressure (%I/~Hg) for most of the sputtered atoms to escape from the specimen surface and not be returned by collision with gas molecules The h~gher sputtering rate attained at low pressure permits etch patterns to be obtained speedily Several metals, VlZ phosphor bronze, copper, pure iron, mild steel, bismuth, cadmmm and Telcoseal 5 (an alloy consisting of 25 per cent chromium in iron with additions of manganese and slhcon) have been cathodically etched satisfactorily and photomicrographs of some of the etched surfaces prepared Generally the cathodlcally etched surfaces were similar to those obtained by chemical etching, but only cathodic etching truly exposed the crystalhne structure of Telcoseal 5 (Author) P T Stroud, Vacuum, 9, 269--273, 1959 18 264 The Measurement of Thermionic Emission in Discharge Tubes A new but simple procedure is described for measuring the zero-field emission I0 m gas-filled discharge devices Probes are not used The noise due to the oscdlatmn of positwe runs m the potential well adjacent to the cathode is detected and amplified The current through the dewce at which the noise drops to a small value is taken to be I0 The emission of oxide cathodes m fuorescent lamps Is found by this technique to increase with increasmg pressure of rare gas The interpretation of this effect is that the rare gas retards the evaporation of barmm from the cathode and permits a higher equilibrium concentration of excess barmm m the cathode for a gwen rate of productmn The higher the rare gas pressure, the lower the rate of escape of barium from the cathode surface and the h~gher the concentration of excess barium in the cathode* (Author) J F Waymouth, Sylvania Technol, 13, 2-10, January 1960 *See April 1960 issue of Sylvama Technologist for correction on p 49 18 11 16 21 22 47 Electrical Clean-up of Gases in Hot Cathode Discharge Tubes See Abstr No 213 18
Vacuum as an Insulator 19.
33
See Abstr No 315
Radiation
19 20 30 56 265 Apparatus for the Controlled Deposition of Op(acal Film Systems. Umted Kingdom Some of the problems of producing multi-
layer interference systems are discussed m relatmn to the design of the deposition plant and film thickness control apparatus A vacuum plant is described in which multi-layer films of evaporated or sputtered layers can be deposited in sequence on a rotating plane surface The thickness of the individual films is controlled by measuring their reflectance or transmittance during deposltmn with a modulated-beam photometer of high sensitivity and stabihty The momtoring light is chopped at frequency of 33 c/s and the output from the photocell amphfled by a tuned low frequency amplifier The condmons for obtaining minimum light scattering in the instrument are discussed The design of the low frequency amphfier is considered m relation to noise level and filter design In conclusion the use of the combined apparatus is described for producing a variety of optical systems such as TIO2 beam-sphtters, BiaOJAu/ B~2Oa heat reflecting mirrors, two-layer anti-reflectmn coatings of Bl2Oa/MgF2 and all-dielectric broad-band filters of MgF2/ZnS (Authors) W Steckelmacher, J M Pansot, L Holland and T Putner, Vacuum, 9, 171-185, 1959 19 266 Optical Properties of Sb, Te, and TI Films m the Vacuum Ultraviolet. Om P Rustgl, W C Walker and (3 L Welssier, J Opt Soc Amer, 51, No 12, 1357-1360, December 1961 19 267 Concept of Cross-Spectral Purity m Coherence Theory. L Mandel, J Opt Soc Amer, 51, No 12, 1342-1351, December 1961 19 268. Attainment of High-Resolution Gratings by Riding under Interferometnc Control George W Stroke, J Opt Sac Ame~ , 51, No 12, 1321-1340, December 1961 19 269 Fringes of Equal Inchnatlon m the Double-Passed Mlcheison Interferometer P Hanharan and D Sen, J Opt Soc Amer, 51, No 6, June 1961 19
270 Color Measurement of Metal Surfaces J M Wdhams, J Opt Soc Amer, 51, No 6, June 1961 19 33 271 The Attainment of Clean Surfaces by Breaking Crystals in Ultra-High Vacuum Umted Kingdom Two experiments are described with the object of determining some of the electronic properties of semiconductor surfaces produced by fracture in high vacuum In one experiment the photoelectric emission is being measured from freshly broken lndmm antlmomde and gallium arsenide, and from cleaved bismuth tellunde The surfaces are produced and the measurements carried out m sealed-off tubes pumped by Ionization gauges The pressures achieved in these tubes are between 10-7 and 10 -9 mmHg In the other experiment, the transverse mobility of Induced surface charge and the photoconductivity are being investigated on germanium surfaces obtained by cleavage in a vacuum of order !0 -1° m m H g This vacuum is obtained in a continuously pumped system with a mercury diffusion pump and ionization gauge Details of the two kinds of tube will be shown (Authors) P C Banbury, G A Barnes, D Haneman and E W J Mitchell, Vacuum, 9, 126-127, 1959
Abstracts 263--271
Use of Zirconium Slntered Getters
16 21 See Abstr No 281
33
16 21 33 The Ceto Getter--its Chemical Structure and Hydrogen Gettermg Properties See Abstr No 282 16 47 36 20 System Design and the Choice of Materials for the " Nimrod " Vacuum System See Abstr No 368
18.
Gaseous Electronics
18 22 30 263. Cathothc Etclung m a Penning Cold Cathode Discharge Umted Kingdom An apparatus for cathodic etching using a Penning cold cathode discharge is described One of the twin cathodes is the specimen to be etched whilst the other is made of alummlum The cathodes are water cooled so that metals of either low melting point or low sputtering rate will not overheat during the cathodic etching The Penning system is used because the glow d~scharge can be maintained at a sufficiently low pressure (%I/~Hg) for most of the sputtered atoms to escape from the specimen surface and not be returned by collision with gas molecules The h~gher sputtering rate attained at low pressure permits etch patterns to be obtained speedily Several metals, VlZ phosphor bronze, copper, pure iron, mild steel, bismuth, cadmmm and Telcoseal 5 (an alloy consisting of 25 per cent chromium in iron with additions of manganese and slhcon) have been cathodically etched satisfactorily and photomicrographs of some of the etched surfaces prepared Generally the cathodlcally etched surfaces were similar to those obtained by chemical etching, but only cathodic etching truly exposed the crystalhne structure of Telcoseal 5 (Author) P T Stroud, Vacuum, 9, 269--273, 1959 18 264 The Measurement of Thermionic Emission in Discharge Tubes A new but simple procedure is described for measuring the zero-field emission I0 m gas-filled discharge devices Probes are not used The noise due to the oscdlatmn of positwe runs m the potential well adjacent to the cathode is detected and amplified The current through the dewce at which the noise drops to a small value is taken to be I0 The emission of oxide cathodes m fuorescent lamps Is found by this technique to increase with increasmg pressure of rare gas The interpretation of this effect is that the rare gas retards the evaporation of barmm from the cathode and permits a higher equilibrium concentration of excess barmm m the cathode for a gwen rate of productmn The higher the rare gas pressure, the lower the rate of escape of barium from the cathode surface and the h~gher the concentration of excess barium in the cathode* (Author) J F Waymouth, Sylvania Technol, 13, 2-10, January 1960 *See April 1960 issue of Sylvama Technologist for correction on p 49 18 11 16 21 22 47 Electrical Clean-up of Gases in Hot Cathode Discharge Tubes See Abstr No 213 18
Vacuum as an Insulator 19.
33
See Abstr No 315
Radiation
19 20 30 56 265 Apparatus for the Controlled Deposition of Op(acal Film Systems. Umted Kingdom Some of the problems of producing multi-
layer interference systems are discussed m relatmn to the design of the deposition plant and film thickness control apparatus A vacuum plant is described in which multi-layer films of evaporated or sputtered layers can be deposited in sequence on a rotating plane surface The thickness of the individual films is controlled by measuring their reflectance or transmittance during deposltmn with a modulated-beam photometer of high sensitivity and stabihty The momtoring light is chopped at frequency of 33 c/s and the output from the photocell amphfled by a tuned low frequency amplifier The condmons for obtaining minimum light scattering in the instrument are discussed The design of the low frequency amphfier is considered m relation to noise level and filter design In conclusion the use of the combined apparatus is described for producing a variety of optical systems such as TIO2 beam-sphtters, BiaOJAu/ B~2Oa heat reflecting mirrors, two-layer anti-reflectmn coatings of Bl2Oa/MgF2 and all-dielectric broad-band filters of MgF2/ZnS (Authors) W Steckelmacher, J M Pansot, L Holland and T Putner, Vacuum, 9, 171-185, 1959 19 266 Optical Properties of Sb, Te, and TI Films m the Vacuum Ultraviolet. Om P Rustgl, W C Walker and (3 L Welssier, J Opt Soc Amer, 51, No 12, 1357-1360, December 1961 19 267 Concept of Cross-Spectral Purity m Coherence Theory. L Mandel, J Opt Soc Amer, 51, No 12, 1342-1351, December 1961 19 268. Attainment of High-Resolution Gratings by Riding under Interferometnc Control George W Stroke, J Opt Sac Ame~ , 51, No 12, 1321-1340, December 1961 19 269 Fringes of Equal Inchnatlon m the Double-Passed Mlcheison Interferometer P Hanharan and D Sen, J Opt Soc Amer, 51, No 6, June 1961 19
270 Color Measurement of Metal Surfaces J M Wdhams, J Opt Soc Amer, 51, No 6, June 1961 19 33 271 The Attainment of Clean Surfaces by Breaking Crystals in Ultra-High Vacuum Umted Kingdom Two experiments are described with the object of determining some of the electronic properties of semiconductor surfaces produced by fracture in high vacuum In one experiment the photoelectric emission is being measured from freshly broken lndmm antlmomde and gallium arsenide, and from cleaved bismuth tellunde The surfaces are produced and the measurements carried out m sealed-off tubes pumped by Ionization gauges The pressures achieved in these tubes are between 10-7 and 10 -9 mmHg In the other experiment, the transverse mobility of Induced surface charge and the photoconductivity are being investigated on germanium surfaces obtained by cleavage in a vacuum of order !0 -1° m m H g This vacuum is obtained in a continuously pumped system with a mercury diffusion pump and ionization gauge Details of the two kinds of tube will be shown (Authors) P C Banbury, G A Barnes, D Haneman and E W J Mitchell, Vacuum, 9, 126-127, 1959