The invention relates to a method 100 for determining a pressure in a vacuum system, wherein the method comprises the steps of: a) generating 101 a plasma in a sample chamber which is fluid-dynamically connected to the vacuum system and which is in electrical contact with a first electrode and a second electrode; b) measuring 102 a current intensity of an electrical current flowing through the plasma between the first electrode and the second electrode; c) measuring 103 a first radiation intensity of electromagnetic radiation of a first wavelength range which is emitted from the plasma, wherein the first wavelength range contains at least a first emission line of a first plasma species of a first chemical element; d) measuring 104 a second radiation intensity of electromagnetic radiation of a second wavelength range which is emitted from the plasma, wherein the second wavelength range contains a second emission line of the first plasma species of the first chemical element or of a second plasma species of the first chemical element, and wherein the second emission line is outside the first wavelength range; and e) determining 105 the pressure in the vacuum system as a function of the measured current intensity, the measured first radiation intensity, and the measured second radiation intensity. Further, the invention relates to a vacuum pressure sensor.

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 cryopumped gas amount estimation device includes: an ultimate pressure determination unit which determines an ultimate pressure of a cryopump vacuumvessel, based on a vacuummeasurement 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 vacuumvessel, based on a vacuummeasurement 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.

Provided are: a vacuum gauge that, with a simple configuration, can accurately diagnose the degree of contamination of the vacuum gauge; and a contamination diagnosis method that, with a simple process, can accurately diagnose the degree of contamination of a vacuum gauge. Provided is a cold cathode ionization vacuum gauge that has a normal operation mode and a contamination diagnosis mode, the cold cathode ionization vacuum gauge comprising: an anode 1 and a cathode 3 that are for measuring vacuum pressure in the normal operation mode; an anode 7 and the cathode 3 that are for measuring the vacuum pressure in the contamination diagnosis mode; and a controller 10 that compares the size of a current measured between the anode 7 and the cathode 3 and the size of a current measured between the anode 1 and the cathode 3.

A diaphragm pressure gauge includes: a structure disposed under pressure to be measured; two diaphragms attached to the structure so as to oppose each other; and a detection element that is fixed to the two diaphragms to detect displacements of the two diaphragms. In each of the two diaphragms, when one of two surfaces is designated an opposing surface and the other surface is designated a non-opposing surface, the structure and the two diaphragms set a space faced by one of the opposing surface and the non-opposing surface as an airtight space to be kept in a reference vacuum, and the other of the opposing surface and the non-opposing surface is subjected to the pressure to be measured.

A diaphragm pressure gauge includes: a structure disposed under pressure to be measured; two diaphragms attached to the structure so as to oppose each other; and a detection element that is fixed to the two diaphragms to detect displacements of the two diaphragms. In each of the two diaphragms, when one of two surfaces is designated an opposing surface and the other surface is designated a non-opposing surface, the structure and the two diaphragms set a space faced by one of the opposing surface and the non-opposing surface as an airtight space to be kept in a reference vacuum, and the other of the opposing surface and the non-opposing surface is subjected to the pressure to be measured.

A method for operating a group of pressure sensors is provided. First and second pressure sensors respectively have first and second pressure measurement ranges, and are arranged to measure the pressure in a common measurement volume, and have measurement ranges that overlap in a range. The method comprises: aa) reading out first and second measurement signals respectively from the first and second pressure sensors substantially simultaneously while the pressure in the common measurement volume is in the overlapping range; bb) stipulating the first measurement signal which has been read out as the adjustment point for the second pressure sensor; cc) determining at least one calibration parameter, in particular a gas-dependent calibration parameter, for the second pressure sensor as a function of the first measurement signal, as a function of the adjustment point for the second pressure sensor, as stipulated in bb), and as a function of the second measurement signal.

A method for operating a group of pressure sensors is provided. First and second pressure sensors respectively have first and second pressure measurement ranges, and are arranged to measure the pressure in a common measurement volume, and have measurement ranges that overlap in a range. The method comprises: aa) reading out first and second measurement signals respectively from the first and second pressure sensors substantially simultaneously while the pressure in the common measurement volume is in the overlapping range; bb) stipulating the first measurement signal which has been read out as the adjustment point for the second pressure sensor; cc) determining at least one calibration parameter, in particular a gas-dependent calibration parameter, for the second pressure sensor as a function of the first measurement signal, as a function of the adjustment point for the second pressure sensor, as stipulated in bb), and as a function of the second measurement signal.

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.