DESIGN OF HELIUM PERMEATION REFERENCE LEAKS WITH GENERATED FLOWS BELOW 10^-14 mol/s

• 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:

  _unreg_wc-2003.TC1-021

Event details:

• IMEKO TC:
• Event name:

  XVII IMEKO World Congress
• Title:

  Metrology in the 3rd Millennium

• Place:

  Dubrovnik, CROATIA
• Time:

  22 June 2003 - 28 June 2003