VSE knjižnice (vzajemna bibliografsko-kataložna baza podatkov COBIB.SI)
  • Calibration of orifice conductance in a vacuum system for desorption measurements
    Sefa, Makfir ; Šetina, Janez
    We have built a measuring system to study desorption of water vapor from elastomer O-rings. Gas desorption (outgassing) from materials in vacuum can be measured by throughput methodk, where a ... desorbed gas flux is calculated from a pressure drop across an orifice. The conductance of the orifice in molecular regime can be calculated from geometrical dimensions. Alternatively it can be calibrated in-situ by introducing known gas flows in the measurement chamber. We will present our measuring system and procedure for in-situ calibration of conductance of the orifice. Calibration was done for different gases: N[sub]2, Ar and H[sub]{2}O. In-situ calibration gives "effective conductance" of the orifice, including effective pumping speed at the downstream side of the conductance. Calibration gas flow was determined by pressure rise method in a known volume using capacitance diaphragm gauge (CDG). Ionization gauge for measurement of pressure at the upstream side of the orifice was calibrated by a spinning rotor gauge (SRG) in the range from 10[sup]{-6} mbar to 10[sup]{-3} mbar. Measured conductance was compared with the calculated values. Uncertainty of calibration of conductance and ionization gauge will be also discussed.
    Vir: Program in knjiga povzetkov = Programme and book of abstracts (Str. 42)
    Vrsta gradiva - prispevek na konferenci
    Leto - 2011
    Jezik - angleški
    COBISS.SI-ID - 864170

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