In a described example, an apparatus includes: at least one electrode having a base on a first surface of a substrate and extending away from the base to an end; a counter-electrode spaced from the end of the at least one electrode, having a first conductive surface facing the end; and a package having a cavity containing the at least one electrode, the substrate, and the counter-electrode, the package having at least one opening configured to allow an atmosphere to enter the cavity.

In a described example, an apparatus includes: at least one electrode having a base on a first surface of a substrate and extending away from the base to an end; a counter-electrode spaced from the end of the at least one electrode, having a first conductive surface facing the end; and a package having a cavity containing the at least one electrode, the substrate, and the counter-electrode, the package having at least one opening configured to allow an atmosphere to enter the cavity.

A sensor for detecting properties of a gas, gas mixture, or a gas or gas mixture containing particles, all collectively referred to as a “gas”. A flow tube contains a pair of electrodes arranged such that at least a portion of the gas flows between the electrodes. A controller applies voltage to the electrodes and measures response data from the electrodes representing the voltage-current relationship and voltage breakdown between the electrodes while the gas is between the electrodes. Based on the response data, the controller determine a concentration of the gas or a concentration of particles within the gas.

A sensor for detecting properties of a gas, gas mixture, or a gas or gas mixture containing particles, all collectively referred to as a “gas”. A flow tube contains a pair of electrodes arranged such that at least a portion of the gas flows between the electrodes. A controller applies voltage to the electrodes and measures response data from the electrodes representing the voltage-current relationship and voltage breakdown between the electrodes while the gas is between the electrodes. Based on the response data, the controller determine a concentration of the gas or a concentration of particles within the gas.

A sensor for detecting properties of a gas, gas mixture, or a gas or gas mixture containing particles, all collectively referred to as a “gas”. A flow tube contains a pair of electrodes arranged such that at least a portion of the gas flows between the electrodes. A controller applies voltage to the electrodes and measures response data from the electrodes representing the voltage-current relationship between the electrodes while the gas is between the electrodes. Based on the response data, the controller determines a concentration of particles within the gas.

A sensor for detecting properties of a gas, gas mixture, or a gas or gas mixture containing particles, all collectively referred to as a “gas”. A flow tube contains a pair of electrodes arranged such that at least a portion of the gas flows between the electrodes. A controller applies voltage to the electrodes and measures response data from the electrodes representing the voltage-current relationship between the electrodes while the gas is between the electrodes. Based on the response data, the controller determines a concentration of particles within the gas.

A discharge ionization detector includes: a gas passage (104, 120) through which an electric-discharge gas is to be passed; a plasma generation electrode (106-108) configured to generate an electric discharge in the gas passage so as to generate plasma from the electric-discharge gas; a sample-gas introduction section (124) through which a sample gas is introduced into the gas passage; a collection electrode (117) configured to collect ions generated from a sample with the plasma; a bias electrode (113) located between the plasma generation electrode and the collection electrode, and configured to create an electric field for guiding the charged particles to the collection electrode; and a DC power unit (131, 133) capable of independently controlling a voltage applied to the bias electrode and a voltage applied to the collection voltage. A peak-shape abnormality in a signal output can be suppressed by appropriately adjusting the voltages.

A discharge ionization detector includes: a gas passage (104, 120) through which an electric-discharge gas is to be passed; a plasma generation electrode (106-108) configured to generate an electric discharge in the gas passage so as to generate plasma from the electric-discharge gas; a sample-gas introduction section (124) through which a sample gas is introduced into the gas passage; a collection electrode (117) configured to collect ions generated from a sample with the plasma; a bias electrode (113) located between the plasma generation electrode and the collection electrode, and configured to create an electric field for guiding the charged particles to the collection electrode; and a DC power unit (131, 133) capable of independently controlling a voltage applied to the bias electrode and a voltage applied to the collection voltage. A peak-shape abnormality in a signal output can be suppressed by appropriately adjusting the voltages.

Particle measurement apparatus comprises an inlet for receiving a gas sample for analysis, a photoionisation chamber, at least one light source arranged to illuminate an interior of the photoionisation chamber, first and second electrodes coupled to a power source and configured to provide a DC potential difference across at least a portion of the photoionisation chamber, and an outlet, together defining a gas flow path from the inlet, through the photoionisation chamber, and towards the outlet.

Particle measurement apparatus comprises an inlet for receiving a gas sample for analysis, a photoionisation chamber, at least one light source arranged to illuminate an interior of the photoionisation chamber, first and second electrodes coupled to a power source and configured to provide a DC potential difference across at least a portion of the photoionisation chamber, and an outlet, together defining a gas flow path from the inlet, through the photoionisation chamber, and towards the outlet.