| AVS 58th Annual International Symposium and Exhibition | |
| Vacuum Technology Division | Monday Sessions |
| Session VT-MoM |
| Session: | Vacuum Measurement, Calibration & Primary Standards, Gas Flow and Permeation |
| Presenter: | Naoki Takahashi, ULVAC Inc., Japan |
| Correspondent: | Click to Email |
Many hot cathode ionization gauges have been developed focused on the lower limit of the pressure measurement. We have also developed the Axial symmetric transmission gauge (AT gauge) which lower limit of the pressure measurement is lower than 10-10 Pa.
On the contrast, stability and reliability are important for the industrial field and metrological traceability field.
Traceability of the vacuum gauge in the range of 1 to 10-4 Pa is established by the spinning rotor vacuum gauge. The uncertainty of the spinning rotor vacuum gauge includes its stability is estimated 1 % to few %. However, the sensitivity of the ionization gauges, which usually are the calibration item of the reference spinning rotor vacuum gauge, changes few % to few tenth %. Sensitivity change was caused by following; geometry change of the electrodes, change of the electron emission region on the hot cathode, contamination of the electrodes, etc.
We have investigated small all metal sealed triode type hot cathode ionization gauge on the contrast to the conventional glass bulbed triode type hot cathode vacuum gauge and all metal sealed BA gauge. The stability of the sensitivity of the small triode ionization gauge was less than 0.5% for 6 month before the huge earthquake happened in Japan. At the disaster, turbo molecular pump was crashed. We could report the sensitivity change of the gauge after the pump change.
We also demonstrate the benefit of the triode vacuum gauge in the contaminated vacuum system.
We will summarise the triode vacuum gauge is better charactristics than conventional glass bulbed triode vacuum gauge and BA gauge in the field of industrial field and metrological traceability field.