1251. Combined leak detector and high sensitivity vacuum gauge

We improved the sensitivity of existing commercial Pirani-vacuum gauges employing the AC method in the vacuum range above 1 Torr. The signals obtained through the use of the AC method yield information related to the specific heat and heat conductivity of gas. The output signal is obtained by two components: the oscillating temperature amplitude, and its phase. The amplitude increases with the decrease of pressure in the vacuum range from the atmosphere to about 1 Torr, which arises from the decrease of the heat capacity with the decrease of gas density. In contrast, the phase decreases monotonically as pressure decreases and the slop of a dΘ/d(log P) is large at higher than 1 Torr. This provides a good advantage for developing a new Pirani gauge with high sensitivity.

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760. A mass-spectroscopic type leak detector of high sensitivity, MKh 1102

Vacuum ◽

10.1016/0042-207x(66)92831-4 ◽

1966 ◽

Vol 16 (5) ◽

pp. 275

Keyword(s):

High Sensitivity ◽

Leak Detector

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High Sensitivity Mass Spectrometer Leak Detector

Review of Scientific Instruments ◽

10.1063/1.1717030 ◽

1960 ◽

Vol 31 (7) ◽

pp. 720-723 ◽

Cited By ~ 21

Author(s):

N. R. Daly

Keyword(s):

Mass Spectrometer ◽

High Sensitivity ◽

Leak Detector

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Helium Leak Testing Between E-11 and E-15 CC/S: Theory and Application

Emerging Technology in Fluids, Structures, and Fluid Structure Interactions: Volume 1, Fluid Dynamics and Fluid Structure Interactions ◽

10.1115/pvp2004-2854 ◽

2004 ◽

Author(s):

Y. Tito Saski

Keyword(s):

Mass Spectrometer ◽

Vacuum Chamber ◽

High Sensitivity ◽

Leak Detector ◽

Quadrupole Mass ◽

Tracer Gas ◽

Gas Leakage ◽

Confidence Factor ◽

Leak Testing ◽

Accumulation Method

Gas leakage between E-11 and E-15 std cc He/s can be measured by a helium accumulation method. The leak detector uses a quadrupole mass spectrometer with a minimum detectable partial pressure of 5E-15 torr. The mass spectrometer is attached to a small ultrahigh vacuum chamber constructed of stainless steel treated for a low hydrogen outgas rate of 2E-15 torr·liter/cm2·s. The chamber has a nozzle to which a test object can be attached. The chamber is also equipped with a non-evaporable getter (NEG) pump that pumps active gases but not noble gases such as helium. The purpose of the NEG and the ultra-low hydrogen outgas feature of the chamber is to maintain low background pressure and high sensitivity of the quadrupole during helium accumulation. Helium tracer gas coming through a defective seal or material is accumulated in this chamber for a few minutes, and the rate of rise of the helium signal is compared with that of a calibrated reference leak. In this manner, leakage down to 1E-15 std cc He/s can be measured with a good confidence factor.

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