An Introduction to Vacuum Technique

Turnbull, A.H.; Barton, R. S.; Riviére, J.C.; Peacock, R. N.

doi:10.1119/1.1970908

Cited by 2 publications

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“…In 1906, Marcello Pirani invented the Pirani gauge which simply consisted of a hot wire and a temperature-dependent resistor in a vacuum tube. Its operating principle was based on the fact that the thermal conduction of a gas is a function of pressure when the pressure is below a certain limit [2]. The temperature of the hot wire is determined by the constant electrical power that heats the wire and the heat loss to the environment by thermal conduction of the surrounding gas.…”

Section: Introductionmentioning

confidence: 99%

The nanogap Pirani—a pressure sensor with superior linearity in an atmospheric pressure range

Khosraviani

Leung

2009

J. Micromech. Microeng.

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We have designed and fabricated a surface micromachined Pirani pressure sensor with an extremely narrow gap between its heater and heatsink (substrate) with superior output linearity in the atmospheric pressure range. The gap size of the device has been reduced to 50 nm by using a layer of PECVD amorphous silicon as a sacrificial layer and a xenon difluoride (XeF 2 ) gas phase etching technique. Such a narrow gap pushes the transition from molecular to continuum heat conduction to pressures beyond 200 kPa. The higher transition pressure increases the measurement range and sensitivity of the gauge in atmospheric pressures. The gas phase etching of the sacrificial layer eliminates stiction problems related to a wet etching process. The active area of the sensor is only a 6 × 50 μm 2 microbridge anchored to the substrate at both ends. An innovative fabrication technique was developed which resulted in a virtually flat microbridge with improved mechanical robustness. This process enabled us to have a very well-controlled gap between the microbridge and the substrate. The device was tested in a constant heater temperature mode with pressure ranges from 0.1 to 720 kPa. The heater power was only 3 mW at 101 kPa (atmospheric pressure), which increased to about 8 mW at 720 kPa. The output sensitivity and nonlinearity of the device were 0.55% per kPa at 101 kPa and ±13% of the output full scale, respectively.

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Section: Introductionmentioning

confidence: 99%

The nanogap Pirani—a pressure sensor with superior linearity in an atmospheric pressure range

Khosraviani

Leung

2009

J. Micromech. Microeng.

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“…Where, T is the absolute temperature of the air in K (the tubes are under atmospheric air with an ambient temperature of 294.15K) and P is the air pressure in Pa. Dm is the gas kinematic diameter of the air molecule i.e. 4•10 -10 m, which is based on the assumption that the air molecules are smooth, rigid and elastic spheres [37].…”

Section: Design and Construction Of A High-vacuum Glazing Fabrication...mentioning

confidence: 99%

The influence of low-temperature surface induction on evacuation, pump-out hole sealing and thermal performance of composite edge-sealed vacuum insulated glazing

2019

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An Introduction to Vacuum Technique

Cited by 2 publications

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The nanogap Pirani—a pressure sensor with superior linearity in an atmospheric pressure range

The nanogap Pirani—a pressure sensor with superior linearity in an atmospheric pressure range

The influence of low-temperature surface induction on evacuation, pump-out hole sealing and thermal performance of composite edge-sealed vacuum insulated glazing

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