Cold cathode ionization vacuum gauge
View Patent ↗A cold cathode ionization vacuum gauge includes an extended anode electrode and a cathode electrode surrounding the anode electrode along its length and forming a discharge space between the anode electrode and the cathode electrode. The vacuum gauge further includes an electrically conductive guard ring electrode interposed between the cathode electrode and the anode electrode about a base of the anode electrode to collect leakage electrical current, and a discharge starter device disposed over and electrically connected with the guard ring electrode, the starter device having a plurality of tips directed toward the anode and forming a gap between the tips and the anode.
1. A cold cathode ionization vacuum gauge comprising:
an extended anode electrode;
a cathode electrode surrounding the anode electrode along its length and forming a discharge space between the extended anode electrode and the cathode electrode;
a removable anode sleeve comprising a thin walled tube on the extended anode electrode that provides an electrical connection to the extended anode electrode and shields the extended anode electrode surface from contaminants along a substantial length thereof in the discharge space;
an electrically conductive guard ring electrode interposed between the cathode electrode and the extended anode electrode about a base of the extended anode electrode and electrically isolated from the cathode electrode to collect leakage electrical current from the extended anode electrode; and
a discharge starter device disposed over and electrically connected with the guard ring electrode, the starter device having a plurality of tips directed toward the extended anode electrode and forming a gap between the tips and the extended anode electrode.
2. The cold cathode ionization vacuum gauge of claim 1 , wherein the plurality of tips is numbered in a range of 2 tips to 8 tips.
3. The cold cathode ionization vacuum gauge of claim 1 , wherein the plurality of tips is numbered in a range of 5 tips to 7 tips.
4. The cold cathode ionization vacuum gauge of claim 1 , wherein the gap between the tips and the extended anode electrode is in a range of between about 500 μm and about 2500 μm.
5. The cold cathode ionization vacuum gauge of claim 1 , wherein the discharge starter device is made of stainless steel.
6. The cold cathode ionization vacuum gauge of claim 1 , wherein a voltage potential difference between the discharge starter device and the extended anode electrode is increased during startup of the gauge.
7. The cold cathode ionization vacuum gauge of claim 1 , further including a baffle across an opening of the cathode electrode to limit flow of sputtered material to a monitored chamber and of material from the monitored chamber into the discharge space, the baffle including a closed central surface facing an end of the extended anode electrode and including peripheral openings.
8. The cold cathode ionization vacuum gauge of claim 1 , wherein the cathode electrode is removable.
9. The cold cathode ionization vacuum gauge as claimed in claim 1 , wherein the anode sleeve is held in place on the extended anode electrode with a friction fit.
10. A cold cathode ionization vacuum gauge comprising:
an extended anode electrode;
a cathode electrode surrounding the extended anode electrode along its length and forming a discharge space between the extended anode electrode and the cathode electrode; and
a removable anode sleeve comprising a thin walled tube on the extended anode electrode that provides an electrical connection to the extended anode electrode and shields the extended anode electrode surface from contaminants along a substantial length thereof in the discharge space.
11. The cold cathode ionization vacuum gauge as claimed in claim 10 , wherein the cathode electrode is removable.
12. The cold cathode ionization vacuum gauge as claimed in claim 10 , wherein the anode sleeve is held in place on the extended anode electrode with a friction fit.
13. The cold cathode ionization gauge as claimed in claim 10 , further comprising a baffle across the opening of the cathode electrode to limit flow of sputtered material to the chamber, the baffle including a closed central surface facing an end of the extended anode electrode and including peripheral openings.
14. A cold cathode ionization vacuum gauge comprising:
an extended anode electrode extending along a longitudinal axis;
a cathode electrode surrounding the extended anode electrode along its length and forming a discharge space between the extended anode electrode and the cathode electrode, the cathode electrode having an opening to receive gas from a monitored chamber; and
a baffle across the opening of the cathode electrode to limit flow of sputtered material to the chamber and of material from the chamber into the discharge space, the baffle including a closed central surface facing an end of the extended anode electrode and including peripheral openings.
15. The cold cathode ionization vacuum gauge of claim 14 , wherein the peripheral openings of the baffle are configured as a plurality of slots disposed to direct flow at an angle with respect to the extended anode electrode.
16. The cold cathode ionization vacuum gauge of claim 15 , wherein the angle of the slots is in a range of about 0 degrees to about 60 degrees.
17. The cold cathode ionization vacuum gauge of claim 14 , wherein the baffle is at least two partitions, a partition facing the chamber having a central aperture and a partition facing the discharge space having the peripheral openings.
18. The cold cathode ionization vacuum gauge of claim 14 , wherein the baffle is at least two partitions, a partition facing the chamber having at least one aperture and a partition facing the discharge space having the peripheral openings, the at least one aperture and the peripheral openings being displaced relative to each other such that the partitions block direct line of sight between the chamber and the cathode parallel to the longitudinal axis.
19. The cold cathode ionization vacuum gauge of claim 14 , further comprising a removable anode sleeve on the anode electrode covering a substantial length thereof in the discharge space.
20. The cold cathode ionization vacuum gauge of claim 19 , wherein the anode sleeve is a thin walled tube friction fit to the extended anode electrode that provides an electrical connection to the extended anode electrode and shields the extended anode electrode surface from contaminants.
21. The cold cathode ionization vacuum gauge of claim 14 , wherein the cathode electrode is removable.
22. The cold cathode ionization vacuum gauge of claim 14 , further comprising:
an electrically conductive guard ring electrode interposed between the cathode electrode and the extended anode electrode about a base of the extended anode electrode and electrically isolated from the cathode electrode to collect leakage electrical current from the extended anode electrode; and
a discharge starter device disposed over and electrically connected with the guard ring electrode, the starter device having a plurality of tips directed toward the extended anode electrode and forming a gap between the tips and the extended anode electrode.
23. A method of performing maintenance of a cold cathode ionization vacuum gauge having an extended anode electrode and a cathode electrode, the method comprising:
removing and replacing an anode sleeve comprising a thin walled tube on the extended anode electrode that provides an electrical connection to the extended anode electrode and shields the extended anode electrode surface from contaminants along a substantial length thereof in a discharge space.
24. The method of claim 23 , further comprising removing and replacing the cathode electrode.
25. The method of claim 23 , wherein the anode sleeve is held in place on the extended anode electrode with a friction fit.