DESIGN OF HELIUM PERMEATION REFERENCE LEAKS WITH GENERATED FLOWS BELOW 10-14 mol/s
Bojan Erjavec, Janez Šetina
Abstract:
The calibration of helium permeation reference leaks below 10-14 mol/s is presented. The reference leak is based on the known construction with a He reservoir and a permeable glass tube leak element. The leak rate is determined in situ using the rate of pressure rise method. The reference leak is equipped with a small calibration volume containing a miniature Ti-getter pump to reduce the residual pressure rise due to outgassing and a spinning rotor gauge (SRG) to measure the rate of He pressure rise. In vacuum metrology, the SRG has been recognized as a transfer standard due to its inertness, high resolution and excellent long-term stability. The He leak rate ranging from 4,0×10-17 mol/s to 1,0×10-14 mol/s, measured at the reference leak temperature of 23°C, is linearly dependent on the He fill pressure ranging from 4,6 Pa up to 1120 Pa. Multiple He flow measurements in the 10-15 mol/s range show that a measurement uncertainty less than 2% can be achieved.
Keywords:
gas permeation, gas flow, spinning rotor gauge, helium reference leak
Download:
PWC-2003-TC1-021.pdf
DOI:
-
Event details
Event name:
XVII IMEKO World Congress
Title:

Metrology in the 3rd Millennium

Place:
Dubrovnik, CROATIA
Time:
22 June 2003 - 28 June 2003
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