Browse - Journal of Vacuum Science & Technology Archives 1964-1982

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Modulation Characteristics of Several Bayard–Alpert Type Gauges

W. J. Lange and J. H. Singleton

J. Vac. Sci. Technol. 3, 319 (1966); http://dx.doi.org/10.1116/1.1492495 (5 pages) | Cited 1 time

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Several Bayard–Alpert-type ion gauges were constructed with a modulator electrode. Curves of ion collector current versus modulator potential were obtained for each gauge and as a function of other electrode potentials and electron current. The most striking difference is found to occur between gauges with and without grid endcaps. For gauges with open end grids, the ion collector current is found to exhibit a maximum at a modulator potential 20–30 V below grid potential. Such a modulation characteristic provides the opportunity to utilize the modulation technique for obtaining the true ion current and spurious current without producing gross potential changes within the gauge. This results in a minimum perturbation of electron orbits and reduces pressure changes due to electron desorption and subsequent adsorption on the modulator since the modulator is continuously bombarded by electrons.

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07.30.Dz

Vacuum gauges

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Sorption of Activated Hydrogen on Vycor Glass

M. J. D. Low and E. S. Argano

J. Vac. Sci. Technol. 3, 324 (1966); http://dx.doi.org/10.1116/1.1492496 (5 pages)

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A flow system incorporating Pirani gauges was used to measure the sorption of hydrogen activated by an rf discharge by Vycor glass. The sorption was dependent on the pressure and the discharge intensity. A rapid, initial adsorption was followed by a slow sorption which obeyed a t^1∕2 law but then decelerated. The kinetics of the thermal release of hydrogen from the Vycor also followed a t^1∕2 law. The data suggest that a steady-state condition, dependent on the hydrogen-atom population in the gas phase, was established on the surface. Hydrogen diffused into the bulk, the rate being a function of the heating of the Vycor surface by hydrogen-atom recombination. Molecular hydrogen diffused to the surface when a sample was heated.

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68.03.Fg	Evaporation and condensation of liquids
68.43.Mn	Adsorption kinetics

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Extended Mass Range Operation of the Monopole Mass Spectrometer

R. E. Grande, R. L. Watters, and J. B. Hudson

J. Vac. Sci. Technol. 3, 329 (1966); http://dx.doi.org/10.1116/1.1492497 (5 pages) | Cited 1 time

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Data are presented demonstrating the degree to which the mass range of monopole and quadrupole mass spectrometers may be extended by various techniques and concomittant effects that this mass range extension has on the other operating parameters such as resolving power, sensitivity, and mass discrimination. These data indicate that high sensitivity and unit resolution may be maintained over a mass range of greater than 600 amu in a monopole instrument of modest size. Further extension is also possible if resolution or sensitivity may be sacrificed.

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07.75.+h

Mass spectrometers

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Cryosorption Pumping of Helium at 4.2 °K

G. E. Grenier and S. A. Stern

J. Vac. Sci. Technol. 3, 334 (1966); http://dx.doi.org/10.1116/1.1492498 (4 pages) | Cited 1 time

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The cryosorption pumping of helium gas by means of Molecular Sieve 5A cryosorption panels has been studied at 4.2 °K and in the pressure range from 10⁻⁷ to 10⁻⁸ Torr. The sticking coefficient of the gas was found to vary from about 0.70 to 0.91 at these pressures, respectively, corresponding to the high pumping speeds of 20000 to 27000 liter∕sec∕ft² of panel. The absorptive capacity for helium was also high down to 10⁻⁸ Torr, but the pumping speed decreased with increasing surface coverage. It is concluded that helium can be pumped effectively in the high-vacuum region with cryosorption panels refrigerated to 4.2 °K.

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07.30.Cy	Vacuum pumps
07.20.Mc	Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment

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Calibration of Low Pressure Penning Discharge Type Gauges

W. J. Lange, J. H. Singleton, and D. P. Eriksen

J. Vac. Sci. Technol. 3, 338 (1966); http://dx.doi.org/10.1116/1.1492499 (7 pages) | Cited 5 times

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Two cold cathode discharge gauges have been calibrated from 10⁻⁴ to 10⁻¹² Torr for argon and hydrogen and to 10⁻¹⁰ Torr for helium, nitrogen, and carbon monoxide. With minor exceptions the sensitivity decreases with pressure; for example, the sensitivity for argon for one gauge was ∼3.5 A∕Torr at 10⁻⁴ Torr, ∼1.5 A∕Torr at 10⁻¹⁰ Torr, and ∼0.1 A∕Torr at 10⁻¹² Torr. The calibration may be represented by a series of linear segments which probably correspond to stable discharge modes in the gauge. In addition, overlap of stable modes occurs and hence the accuracy of pressure measurement is difficult to predict even with a detailed calibration of a specific gauge.

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07.30.Dz

Vacuum gauges

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Comparison of the Trigger Discharge Gauge with an Ionization Gauge and a Partial Pressure Analyzer

J. R. Young

J. Vac. Sci. Technol. 3, 345 (1966); http://dx.doi.org/10.1116/1.1492500 (5 pages) | Cited 2 times

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The trigger discharge gauge has been compared with a thoroughly processed Bayard-Alpert ionization gauge capable of measuring pressure to 2×10⁻¹¹ Torr. Differences no greater than a factor of two were observed between the two gauges for pressures between 1×10⁻¹¹ and 10⁻⁴ Torr. By subtracting the x-ray limit of 2×10⁻¹¹ Torr, the ionization gauge readings were corrected and indicated fair agreement with the trigger discharge gauge down to 1×10⁻¹¹ Torr. Comparison of these gauges with a partial pressure analyzer indicates the ionization gauge output decreased linearly down to 10⁻¹⁰ Torr and saturated at 2.6×10⁻¹¹ Torr while the trigger discharge gauge current varied as P^1.2 in the range between 10⁻⁷ Torr to 5×10⁻¹² Torr—the lowest indicated pressure achieved while operating the partial pressure analyzer. It is concluded that slow and continued ion desorption and outgassing of the ionization gauge is responsible for differences of more than a factor of two in trigger gauge and ionization gauge readings.

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07.30.Dz

Vacuum gauges

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Response of the Trigger Discharge Gauge

P. J. Bryant and C. M. Gosselin

J. Vac. Sci. Technol. 3, 350 (1966); http://dx.doi.org/10.1116/1.1492501 (2 pages) | Cited 1 time

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Abstract Unavailable

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07.30.Dz

Vacuum gauges

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Low Cost, 1300 °C Vacuum Furnace

Stuart A. Hoenig

J. Vac. Sci. Technol. 3, 351 (1966); http://dx.doi.org/10.1116/1.1492502 (2 pages)

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Abstract Unavailable

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07.30.Kf	Vacuum chambers, auxiliary apparatus, and materials
07.20.Hy	Furnaces; heaters

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Ultrahigh Vacuum Produced By A Combination Of Turbomolecular And Titanium Sublimation Pumping

R. A. Outlaw

J. Vac. Sci. Technol. 3, 352 (1966); http://dx.doi.org/10.1116/1.1492503 (3 pages)

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Abstract Unavailable

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07.30.-t

Vacuum apparatus

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Residual Gases in Oil and Mercury Pumped Systems

J. H. Singleton

J. Vac. Sci. Technol. 3, 354 (1966); http://dx.doi.org/10.1116/1.1492504 (2 pages) | Cited 1 time

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Abstract Unavailable

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07.30.Bx

Degasification, residual gas

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Ultrasonic Particle Feeder for Flash Evaporation

J. R. Eckardt and R. N. Peacock

J. Vac. Sci. Technol. 3, 356 (1966); http://dx.doi.org/10.1116/1.1492505 (1 page) | Cited 1 time

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43.35.-c	Ultrasonics, quantum acoustics, and physical effects of sound
81.15.-z	Methods of deposition of films and coatings; film growth and epitaxy