Terminology in vacuum measurements

Gulyaev, M. A.

doi:10.1007/bf00984843

Cited by 4 publications

(2 citation statements)

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“…Some of the most sensitive pressure gauges ionize residual gas molecules and measure the resulting electrical current. Such ionization gauges require an empirical calibration, accounting for the efficiency of the ionization technique employed, which varies across molecular species and filament materials, and may change over time [6][7][8]. Additionally, the production of cations and their associated electrons, inherent to ionization gauges, can have a detrimental effect on conditions within an experimental chamber.…”

Section: Introductionmentioning

confidence: 99%

Absolute pressure and gas species identification with an optically levitated rotor

Blakemore

Martin

Fieguth

et al. 2020

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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We describe a novel variety of spinning-rotor vacuum gauge in which the rotor is a ∼4.7-µmdiameter silica microsphere, optically levitated. A rotating electrostatic field is used to apply torque to the permanent electric dipole moment of the silica microsphere and control its rotational degrees of freedom. When released from a driving field, the microsphere's angular velocity decays exponentially with a damping time inversely proportional to the residual gas pressure, and dependent on gas composition. The gauge is calibrated by measuring the rotor mass with electrostatic co-levitation, and assuming a spherical shape, confirmed separately, and uniform density. The gauge is crosschecked against a capacitance manometer by observing the torsional drag due to a number of different gas species. The techniques presented can be used to perform absolute vacuum measurements localized in space, owing to the small dimensions of the microsphere, as well as measurements in magnetic field environments. In addition, the dynamics of the microsphere, paired with a calibrated vacuum gauge, can be used to measure the effective molecular mass of a gas mixture without the need for ionization, and at pressures up to approximately 1 mbar.

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Section: Introductionmentioning

confidence: 99%

Absolute pressure and gas species identification with an optically levitated rotor

Blakemore

Martin

Fieguth

et al. 2020

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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“…An earlier review of experimental work has been followed by a companion review of the theory of electron-impact ionization (103). Several other papers have been concerned with reviews of available data and calculation of rate coefficients (104,105,106).…”

Section: Ionization By Electron Impactmentioning

confidence: 99%

Committee 3: Collision Cross Sections and Line Broadening

Seaton¹

1970

Trans. Int. Astron. Union

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Two review articles have been published (1,2).1.1.Collision broadening by neutral atoms.The continued study of widths and shifts produced by neutral atom impacts at low densities has shown that the Van der Waals interaction ( — C6r−6)as used, for example, in (3), is an inadequate representation of the interatomic potential. The classical theory for a Leonard-Jones potential(C12r−12— C6r−6)has been developed (4) and subjected to experimental test (5). Further improvements result from introducing a term C8r−8in the potential (6) and from allowance for quasi-static effects (7). Applications to broadening by H—atom impact are discussed in (8).

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Comparison of the work of crack propagation determined by the Gulyaev and Drozdovskii methods

Kosarev¹

1970

Met Sci Heat Treat

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Terminology in vacuum measurements

Cited by 4 publications

References 0 publications

Absolute pressure and gas species identification with an optically levitated rotor

Absolute pressure and gas species identification with an optically levitated rotor

Committee 3: Collision Cross Sections and Line Broadening

Comparison of the work of crack propagation determined by the Gulyaev and Drozdovskii methods

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