A system of measuring and correcting for distortions in homodyne systems and a method for operating a data processing system to provide an estimate of distortions in homodyne systems are disclosed. The method for operating a data processing system to provide an estimate of a distortion introduced by a homodyne system when the homodyne system processes a time a multi-tone time domain input signal, x(t), to obtain a time domain output signal, y(t) includes receiving a frequency spectrum, X(f), of the multi-tone time domain input signal, x(t) and measuring an output frequency spectrum, Y(f), when the homodyne system operates on x(t). A plurality of parameters of a model that represents a linear frequency response of the homodyne system when operating on X(f) to arrive at Y(f) by fitting the model to Y(f) and X(f) is determined, and the model is applied to X(f) and Y(f) to estimate the distortions.

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.

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. The cathode includes a first cathode plate including a through hole through which the anode extends, and a storage portion configured to store the electromagnetic wave source, a second cathode plate arranged separately from the first cathode plate, a third cathode plate arranged between the first cathode plate and the second cathode plate to be in contact with the first cathode plate, and a member configured to surround the first cathode plate, the second cathode plate, and the third cathode plate.

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. The cathode includes a first cathode plate including a through hole through which the anode extends, and a storage portion configured to store the electromagnetic wave source, a second cathode plate arranged separately from the first cathode plate, a third cathode plate arranged between the first cathode plate and the second cathode plate to be in contact with the first cathode plate, and a member configured to surround the first cathode plate, the second cathode plate, and the third cathode plate.

A cold cathode ionization gauge (CCIG) includes an extended anode, a cathode surrounding the anode along a length of the anode, and a feedthrough insulator supporting the anode. The cathode forms a discharge space around the anode to enable formation of a plasma between the anode and the cathode and a resultant ion current flow into the cathode. The CCIG further includes a magnet applying a magnetic field through the discharge space to lengthen free electron paths to sustain the plasma. A shield is electrically isolated from the insulator and shields the insulator from electrons of the plasma. The shield may be mounted to the cathode and surrounds and is spaced from the anode. An electric controller applies voltage between the anode and the cathode to create ionization with plasma discharge between the anode and the cathode, the controller determining pressure based on measured ion current flow to the cathode.

A cold cathode ionization gauge (CCIG) includes an extended anode, a cathode surrounding the anode along a length of the anode, and a feedthrough insulator supporting the anode. The cathode forms a discharge space around the anode to enable formation of a plasma between the anode and the cathode and a resultant ion current flow into the cathode. The CCIG further includes a magnet applying a magnetic field through the discharge space to lengthen free electron paths to sustain the plasma. A shield is electrically isolated from the insulator and shields the insulator from electrons of the plasma. The shield may be mounted to the cathode and surrounds and is spaced from the anode. An electric controller applies voltage between the anode and the cathode to create ionization with plasma discharge between the anode and the cathode, the controller determining pressure based on measured ion current flow to the cathode.

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. The cathode includes a first cathode plate including a through hole through which the anode extends, and a storage portion configured to store the electromagnetic wave source, a second cathode plate arranged separately from the first cathode plate, a third cathode plate arranged between the first cathode plate and the second cathode plate to be in contact with the first cathode plate, and a member configured to surround the first cathode plate, the second cathode plate, and the third cathode plate.

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. The cathode includes a first cathode plate including a through hole through which the anode extends, and a storage portion configured to store the electromagnetic wave source, a second cathode plate arranged separately from the first cathode plate, a third cathode plate arranged between the first cathode plate and the second cathode plate to be in contact with the first cathode plate, and a member configured to surround the first cathode plate, the second cathode plate, and the third cathode plate.

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, 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.