摘要:

This paper describes recent advances in the design and operation of automated systems which lock the work in and out of the evaporation area. The latter is maintained under vacuum at all times with the sources in a continuously ready state. Systems have been produced for up to five sequential or graded coatings and for alloys. Each deposition is monitored and each step must be completed to specification before the next step can be started. Very high production rates can be achieved, and users report the end product superior to that obtained from batch systems opened to air between loads. Operation of such systems over long periods has created some unique operating problems and solutions.

ISSN:0022-5355    

DOI:10.1116/1.1316338

出版商:American Vacuum Society    

年代:1971

数据来源: AIP

摘要:

The ionization yield for various gases has been examined utilizing the lateral surface of a single graphite whisker as the ionizer. The process of ion formation at or near the inert-type surface has been compared with data from a platinum wire ionizer. The dependence of ion yield upon applied voltage has been obtained and plotted for a range of values from 7.5 to 20 kV. A series of gases were examined which provided a range of values for the parameters of interest such as ionization potential. The gases studied included helium, ammonia, carbon monoxide, carbon dioxide, sulfur dioxide, methane, and ethylene.

ISSN:0022-5355    

DOI:10.1116/1.1316339

出版商:American Vacuum Society    

年代:1971

数据来源: AIP

摘要:

The emission decays of the oxide-coated cathode due to the contamination of the positive electrode have been studied with barium fluoride as the contaminant. All the experimental processes—positive electrode (anode) cleaning by electron bombardment, vacuum deposition of a known amount of the contaminant onto the anode, and dc and pulsed emission measurement—were carried out in a vacuum system using movable molybdenum anodes. As soon as an anode voltage higher than about 10 V was applied, the emission decayed to a minimum value, and then increased slowly. The minimum emission seemed to occur when the incoming rate of poisoning material to the cathode became equal to its liberation rate from the cathode. The emission decay was detected even with5×10−8 g/cm2of barium fluoride. The emission recovered gradually when the anode was replaced by a clean one. The decay-recovery process proved repeatable at least 15 times and the activation energy of the recovery was estimated to be about 36–45 kcal/mole, when the amount of the contaminant was2×10−6 g/cm2. The decay and recovery processes are discussed.

ISSN:0022-5355    

DOI:10.1116/1.1316340

出版商:American Vacuum Society    

年代:1971

数据来源: AIP

摘要:

Analysis of residual gases has been performed on large numbers of production television tubes. This paper describes the system, CRT break-in equipment, and quadrupole RGA sampling procedure. With the system background pressure in the10−11 Torrrange, CRT gases were released, analyzed, and recorded. Included is data on residual gases during the oxide cathode processing, after final tube production and after-life test. The difficulty encountered in relating data on residual gases from final production tubes against the data from life-tested tubes which are at a lower pressure (4–8×10−9 Torr) is outlined along with the effects of phonic desorption of gases during the CRT break-in. The value of residual gas analysis in evaluating the effects of changes in manufacturing processes is discussed.

ISSN:0022-5355    

DOI:10.1116/1.1316341

出版商:American Vacuum Society    

年代:1971

数据来源: AIP

摘要:

The electrolysis of small crystals ofCaF2,MgF2, and NaCl has been observed in a high-vacuum system by monitoring the gaseous species evolved with a quadrupole residual gas analyzer. As would be expected the nature of the evolved species is determined by the electrode material. WhenCaF2was electrolyzed using carbon electrodes, as many as 20 different carbon fluorides were observed. Atomic fluorine was also generated. The simplicity of the apparatus and the substantial quantity of gas evolved suggest that this technique might be useful for admitting small quantities of unusual and/or reactive gaseous species to a vacuum system in an easily controllable manner.

ISSN:0022-5355    

DOI:10.1116/1.1316343

出版商:American Vacuum Society    

年代:1971

数据来源: AIP

摘要:

High-purity silver powder (99.97%) subjected to isothermal outgassing, oxygen adsorption, outgassing, and chemical reduction (OAOR cycling) at 320 °C has been shown to contain 750 ppm of unreported volatile impurities and to be reproducible to the chemisorption of oxygen and other gases. To determine some of the volatile contaminants present before cycling and the effect of cycling on their release by the sample, a residual gas analyzer was used to study the gases which were desorbed by heating a sample of silver powder in stages to 900 °C in vacuo. A second sample was subjected to five OAOR cycles at 320 °C and then outgassed in stages up to 900 °C. During the isothermal outgassing of the uncycled sample, the partial pressures of carbon monoxide, carbon dioxide, oxygen, water, argon, and sulfur dioxide increased by as much as ten times between 300 ° and 410 °C and again between 540 ° and 565 °C. The increase in the residual gases results from a combination of bulk diffusion, surface reaction and desorption, and possibly the release of gases trapped in voids in the powder. Similar increases were seen for the cycled sample, except that sharper peaks were found in the temperature ranges of 505 °–535 °C and 720 °–730 °C. A third sample was OA cycled at 500 °C and outgassed in the same manner. Similar increases of the same impurities were found between 740 °–760 °C. Since silver powder sinters on outgassing above 200 °C, cleaning by chemical reduction cannot be carried out without strongly sintering the sample.

ISSN:0022-5355    

DOI:10.1116/1.1316344

出版商:American Vacuum Society    

年代:1971

数据来源: AIP

摘要:

The system consists of a 60 ° magnetic sector mass spectrometer and a bakeable stainless-steel vacuum system which is oil-diffusion pumped and liquid-nitrogen trapped. The technique developed to analyze gas samples ranging from10−3to less than10−7 Torrliter quantities is described. Gases of interest includeN2, CO,H2,CH4,CO2,O2,SO2,H2S,H2O, and Ar. Minimum detectabilities extend from10−7 Torrliter forN2and CO to less than10−8 Torrliter for argon. Sample-system interactions and the limitations they place on the analysis are also discussed.

ISSN:0022-5355    

DOI:10.1116/1.1316345

出版商:American Vacuum Society    

年代:1971

数据来源: AIP

摘要:

Ion-electron converters with low background current have been applied for the investigation of residual gas mass spectra. From the abundance distribution of the secondary electrons, measured with scintillation and surface barrier detectors, counting losses can be determined for different ion masses. Ion currents as low as some10−22A are measurable. The corresponding error limits are considered by a statistical analysis including the background current. Criteria are given to distinguish a mass peak from the background within a definite error probability.

ISSN:0022-5355    

DOI:10.1116/1.1316346

出版商:American Vacuum Society    

年代:1971

数据来源: AIP