A photoionization detector comprised of a gas discharge lamp that ionizes molecules of interest to create ionized molecules and electrons and a sensor having at least one opening for UV light to pass through and electrically conductive patterns on at least one of the top and bottom surfaces of the plate, including at least a negative electrical potential pattern and an electron collecting electrode pattern. The ionized molecules are collectable by a bias electrode and electrons are collectable by a collector electrode. The negative electrical potential pattern includes a linear portion and a polarization plate. The electron collecting electrode pattern includes a wire suspended across the at least one opening and a linear portion on the surface opposite the wire. The electrically conductive patterns can further include a grounded potential conductive pattern having a first portion on the top surface and a second portion on the bottom surface.

A photoionization detector comprised of a gas discharge lamp that ionizes molecules of interest to create ionized molecules and electrons and a sensor having at least one opening for UV light to pass through and electrically conductive patterns on at least one of the top and bottom surfaces of the plate, including at least a negative electrical potential pattern and an electron collecting electrode pattern. The ionized molecules are collectable by a bias electrode and electrons are collectable by a collector electrode. The negative electrical potential pattern includes a linear portion and a polarization plate. The electron collecting electrode pattern includes a wire suspended across the at least one opening and a linear portion on the surface opposite the wire. The electrically conductive patterns can further include a grounded potential conductive pattern having a first portion on the top surface and a second portion on the bottom surface.

A system for equalizing a pressure in an ionization chamber of a radiation device is provided. The system may include the ionization chamber including: a chamber housing including one or more chamber walls; a chamber volume inside the chamber housing, the chamber volume being filled with a radiation sensitive material; and a pressure adjustment apparatus operably coupled to the chamber volume via at least one wall of the one or more chamber walls, the pressure adjustment apparatus being configured to equalize a first pressure of the radiation sensitive material inside the chamber volume and a second pressure of ambient air outside the chamber housing.

A system for equalizing a pressure in an ionization chamber of a radiation device is provided. The system may include the ionization chamber including: a chamber housing including one or more chamber walls; a chamber volume inside the chamber housing, the chamber volume being filled with a radiation sensitive material; and a pressure adjustment apparatus operably coupled to the chamber volume via at least one wall of the one or more chamber walls, the pressure adjustment apparatus being configured to equalize a first pressure of the radiation sensitive material inside the chamber volume and a second pressure of ambient air outside the chamber housing.

A method for detecting particles in a gas of a process environment present in a process chamber, the method comprising the steps of: guiding the gas with the particles into an ionization and charging unit (11) being in fluid communication with the process chamber, wherein the ionization and charging unit has an anode (12) and a cathode (13) and is adapted and configured to at least partly ionize said gas and to charge at least some of said particles; igniting and sustaining a discharge in said gas by applying a voltage between said anode and said cathode of the ionization and charging unit; measuring a current flowing from or to the anode and/or from and to the cathode; detecting the particles based on an AC component or a transient of the measured current. The invention is further directed to an apparatus for detecting particles, to a coating system comprising such an apparatus and to a use of ionization unit.

A photoionization detector sensor comprised of a plate having top and bottom surfaces and an electrically insulating substrate; at least one opening in the plate for UV light to pass through; a negative electrical potential pattern on at least one of the top and bottom surfaces; and an electron collecting electrode pattern having a wire suspended across the at least one opening. The negative electrical potential pattern includes a linear portion and a polarization plate. The electron collecting electrode pattern further includes a linear portion on the surface opposite the wire. The electrically conductive patterns can further include a grounded potential conductive pattern having a first portion on the top surface and a second portion on the bottom surface.

A photoionization detector sensor comprised of a plate having top and bottom surfaces and an electrically insulating substrate; at least one opening in the plate for UV light to pass through; a negative electrical potential pattern on at least one of the top and bottom surfaces; and an electron collecting electrode pattern having a wire suspended across the at least one opening. The negative electrical potential pattern includes a linear portion and a polarization plate. The electron collecting electrode pattern further includes a linear portion on the surface opposite the wire. The electrically conductive patterns can further include a grounded potential conductive pattern having a first portion on the top surface and a second portion on the bottom surface.