An ionization gauge includes an anode, a cathode, and an electromagnetic wave source. The cathode includes a first cathode plate having a through hole through which the anode passes, a storage portion configured to store the electromagnetic wave source, and a passage arranged between the storage portion and the through hole and configured to pass an electromagnetic wave generated by the electromagnetic wave source.

An ionization gauge includes an anode having a rod shape, and a cathode including a cathode plate having a through hole through which the anode extends. A shape of the through hole on a section along an axial direction of the anode includes a concave portion sandwiched between two convex portions.

An ionization gauge includes an anode having a rod shape, and a cathode including a cathode plate having a through hole through which the anode extends. A shape of the through hole on a section along an axial direction of the anode includes a concave portion sandwiched between two convex portions.

The disclosure includes an ionization chamber, a first electron multiplier, and a second electron multiplier. The ionization chamber is configured to receive gas molecules from an environment at a pressure. The first electron multiplier is configured to receive a plurality of photons from a photon source, generate a first plurality of electrons from the plurality of photons, and discharge the first plurality of electrons into the ionization chamber to generate a plurality of gas ions from at least a portion of the gas molecules. The second electron multiplier is configured to receive the plurality of gas ions from the ionization chamber and generate a second plurality of electrons from the plurality of gas ions that is proportional to a quantity of the plurality of gas ions. A quantity of electrons of the second plurality of electrons is indicative of the pressure.

A photoionization sensor assembly includes a housing defining a chamber with a first end and an opposing second end and being permeable to the analyte gas and non-analyte gases. A radiation source is structured to emit photons into the chamber. A first, second and third electrode are positioned in the chamber. The photons ionize the analyte gas, are insufficient to ionize the non-analyte gases, and causing ejection of photoelectrons from the third electrode. A controller is structured to receive a measurement of a total pressure and electrically bias the electrodes to collect the photoelectrons on the first and second electrodes in a ratio dependent on the total pressure. The controller is structured to determine the ratio of photoelectrons that are collected on the first and second electrodes at the total pressure and determine an amount of electrical current due to ionization by correcting the measured current using the determined ratio.

A total pressure cold cathode ionization gauge is disclosed. An inverted magnetron electrode design is capable of simultaneously detecting and measuring total gas pressure in a high vacuum system, along with partial pressures of one or more gases, such as hydrogen, helium and water. In addition, a leak detector, such as a helium leak detector, is disclosed with a compact counterflow arrangement of a gas inlet passage to an ion detection passage.

A total pressure cold cathode ionization gauge is disclosed. An inverted magnetron electrode design is capable of simultaneously detecting and measuring total gas pressure in a high vacuum system, along with partial pressures of one or more gases, such as hydrogen, helium and water. In addition, a leak detector, such as a helium leak detector, is disclosed with a compact counterflow arrangement of a gas inlet passage to an ion detection passage.

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.

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.

A cold cathode ionization gauge includes multiple cathodes providing different spacings between the cathodes and an anode. The multiple cathodes allow for pressure measurements over wider ranges of pressure. A first cathode with a larger spacing may provide current based on Townsend discharge; whereas, a second cathode having a smaller spacing may provide current based on both Townsend discharge at higher pressures and on Paschen's Law discharge at still higher pressures. A feature on the second cathode may support Paschen's Law discharge. Large resistances between the cathodes and a return to power supply enable control of output profiles to extend the pressure ranges with accurate responses and avoid output minima. Pressure measurements may be made based on currents from respective cathodes dependent on the outputs of the cathodes through the wide pressure range of measurement. The multiple cathodes may also provide measurements that avoid the discontinuities found in current outputs of the respective cathodes.