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.

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.

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 cryopumped gas amount estimation device includes: an ultimate pressure determination unit which determines an ultimate pressure of a cryopump vacuum vessel, based on a vacuum measurement signal representing the degree of vacuum in the cryopump vacuum vessel; and a cryopumped gas amount quantification unit which includes a cryopumped gas amount quantification relation correlating the ultimate pressure with a cryopumped gas amount estimated value and converts the ultimate pressure into the cryopumped gas amount estimated value.

A cryopumped gas amount estimation device includes: an ultimate pressure determination unit which determines an ultimate pressure of a cryopump vacuum vessel, based on a vacuum measurement signal representing the degree of vacuum in the cryopump vacuum vessel; and a cryopumped gas amount quantification unit which includes a cryopumped gas amount quantification relation correlating the ultimate pressure with a cryopumped gas amount estimated value and converts the ultimate pressure into the cryopumped gas amount estimated value.

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.

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.

A vacuum feedthrough (10) which is constructed in radial layers comprises the following elements (from inwards to outwards): a lens element (11), a first ring (12) made of glass, a first hollow cylinder (13) made of a first dielectric material, a first electrically conductive layer (18), a second hollow cylinder (14) made of glass, a third hollow cylinder (15) made of ceramic, a second ring made of glass (16), anda frame (17) made of metal. On the basis of the vacuum feedthrough, the invention additionally relates to an electrode assembly, to a device for generating a DBD plasma discharge, to a measuring device for characterizing a pressure and/or a gas composition, and to a method for operating the measuring device.

Devices and corresponding methods can be provided to test an ionization gauge, such as a hot cathode ionization gauge, for leakage currents and to respond to the leakage currents to improve pressure measurement accuracy. Responding to the leakage current can include applying a correction to a pressure measurement signal generated by the gauge based on the leakage current. Responding to the leakage current can also include removing contamination causing the leakage current, where the contamination is on electrical feedthrough insulators or other gauge surfaces. Testing and correcting for leakage currents and removing contamination can be completed with the ionization pressure gauge in situ in its environment of use, and while the gauge remains under vacuum.