Regensburg 2002 – wissenschaftliches Programm
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VA: Vakuumphysik und Vakuumtechnik
VA 3: Vakuummesstechnik
VA 3.4: Vortrag
Montag, 11. März 2002, 16:10–16:30, H47
Comparison of the stability of hot and cold cathode ionization gauges — •Detian Li and Karl Jousten — Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin
When ionization gauges are used as reference or secondary standards, the stability of gauges are most important. Generally, in calibration services only hot cathode gauges are used as reference or secondary standards. Some traditional reasons to object the use of cold cathode gauges are the presence of discontinuities in the current versus pressure characteristic, the ignition delay at very low pressure, and the bad stability. But the modern inverted magnetron designs are believed to avoid many of these problems. However, no hard data have been published on these matters to prove the improvements. This paper will present the experimental results of three hot cathode gauges and two inverted magnetrons against a primary high-vacuum standard over the range (10−7 to 10−3 Pa with gases of N2, Ar, He and H2, respectively. In a continuous observation for 72h at a constant pressure of about 10−4 Pa, hot cathode gauges had better stabilities than inverted magnetrons in N2, Ar and He, but all gauges behaved similar in H2. Repeating calibrations over a period of three months showed that all gauges had similar stabilities in N2, Ar and He. Especially, the stability of inverted magnetrons was better than that of hot cathode gauges in H2. For different gases, the discontinuities of inverted magnetrons occurred at different pressures, which will make their calibrations more troublesome.