Abstract: A cold-cathode ionization or Penning vacuum meter with an ignition system to increase the meter's usefulness at very low pressures. The ignition system comprises an additional anode and at least one additional cathode mounted adjacent to the primary, measuring, cathode and anode and within the same magnetic field as the primary cathode and anode. The at least one additional cathode and the anode are substantially smaller than the measuring cathode and the anode and serve to ignite or start the ionization of the atomosphere whose pressure needs to be measured.

Abstract: A calibrated gas source for testing leakage indicators composed of a housing divided into two chambers by a partition having a gas passage between the chambers, a mass of liquefied gas filling one of the chambers, a valve associated with the passage for permitting gas to pass from the one chamber to the other chamber when it is under a certain excess pressure, and a capillary passage between the other chamber and the surrounding environment.