The invention refers to an optical measurement apparatus (10) with an optical device (18,20,22) and a liquid sample vessel (12) for measuring an optical parameter of a liquid sample (13) in the liquid sample vessel (12), comprising a drying circuit circulating drying air for venting the sample vessel (12), wherein the drying circuit comprises a mechanical water stop means (100) in the course of the drying circuit, the water stop means (100) comprising a conduit body (102) with a water-absorbing swelling element (120) arranged within the conduit body (102). The water stop means is simple and inexpensive and reliably protects all elements downstream of the water stop means from a water ingress upstream of the water stop means.

A device for viewing and/or illuminating a target surface in an evacuated chamber having condensable vapor therein, the device comprising: a first section with a through hole having a first end with a first opening and a second end with a second opening; and a second section having a chamber comprising a first portion with a first opening, a second portion with a second opening and a gas inlet, where the second opening is covered with a first window, said first section is attached with the first end to the first portion of the chamber allowing free passage between the chamber and the first section, said gas inlet is connectable to a gas reservoir for feeding a gas into the chamber for prohibiting the first window in the chamber for being contaminated of the condensable vapor.

A device may be provided for element analysis of materials by means of optical emission spectroscopy, particularly by means of laser-induced plasma spectroscopy, said device having: means for exciting a plasma from a partial quantity of a test sample made of the material to be analyzed; means for detecting and for spectral analysis of optical radiation emitted from the plasma; beam guidance means for guiding at least a part of the optical radiation emitted from the plasma to the means for detecting and spectral analysis; and means for flushing at least one partial region of the device with an inert gas, wherein the beam guidance means are at least one capillary tube, which additionally serves to guide the inert gas. A method may be provided for element analysis of materials by means of optical emission spectroscopy using the device.

A method and apparatus for cleaning vacuum ultraviolet (VUV) optics (e.g., one or more mirrors of a VUV) of a substrate inspection system is disclosed. The cleaning system ionizes or disassociates hydrogen gas in a VUV optics environment to generate hydrogen radicals (e.g., H*) or ions (e.g., H.sup.+, H.sub.2.sup.+, H.sub.3.sup.+, which remove water or hydrocarbons from the surface of the one or more mirrors. The one or more VUV mirrors may include a reflective material, such as aluminum. The one or more VUV mirrors may have a protective coating to protect the reflective material from any detrimental reaction to the hydrogen radicals or ions. The protective coating may include a noble metal.

A spark stand for an optical emission spectrometer, comprising: a spark chamber; a gas inlet for flowing gas into the spark chamber; a gas outlet for carrying gas from the spark chamber; wherein one or more internal surfaces of the spark chamber, gas inlet and/or gas outlet comprise an anti-adhesion material. The anti-adhesion material can enable reduced adhesion of ablated material, such as metallic dusts for example, onto the surfaces within the spark stand.

A particle concentration measurement system includes a first window and a second window in a housing. The first window and the second window respectively define a first end and a second end of an interaction region between the first window and the second window. The system also includes a particle-laden gas inlet through a wall of the housing between the first window and the second window. The particle-laden gas inlet introduces particle-laden gas from an environment that includes particles mixed with other materials into the interaction region. A first set of clean gas inlets through the wall of the housing are at different radial positions of the housing and at a first axial location of the housing, and a second set of clean gas inlets through the wall of the housing are at different radial positions of the housing and at a second axial location of the housing.

An apparatus includes at least one Terahertz (THz) device that transmits or receives THz radiation or transmits and receives THz radiation. The apparatus also provides a flow of protective gas in at least one portion of the beam path of the THz radiation.

A handheld LIES device includes a laser source for generating a laser beam, a spectrometer subsystem for analyzing a plasma generated when the laser beam strikes a sample, and a nose section including an end plate with an aperture for the laser beam and for receiving plasma radiation and an optic spaced from the end plate defining with the end plate a cavity therebetween. An atmospheric purge subsystem includes an air pump with an intake exposed to the atmosphere and a conduit connected to the air pump providing an atmospheric gas mixture to the nose section cavity to purge the cavity of contaminants and keep the optic clean as the atmospheric gas mixture exits the cavity through the end plate aperture.

The present invention provides a welding seam tracking sensor, which belongs to the technical field of sensors, and alleviates the problem of detection performance reduction of a sensor. The welding seam tracking sensor comprises a sensor housing, a protection cover and a protection sheet; the protection cover is mounted on the bottom of the sensor housing, an air inlet is provided on the upper surface of the protection cover, and a blowing hole is provided on the bottom of the sensor housing. The air inlet and the blowing hole is closely connected; there is a visual hole and a laser hole in the bottom of the protection cover, a transverse slot is formed inside the protection cover, a socket is opened on the side wall of the protection cover, the protection sheet is inserted into the slot through the socket.

A particle concentration measurement system includes a first window and a second window in a housing. The first window and the second window respectively define a first end and a second end of an interaction region between the first window and the second window. The system also includes a particle-laden gas inlet through a wall of the housing between the first window and the second window. The particle-laden gas inlet introduces particle-laden gas from an environment that includes particles mixed with other materials into the interaction region. A first set of clean gas inlets through the wall of the housing are at different radial positions of the housing and at a first axial location of the housing, and a second set of clean gas inlets through the wall of the housing are at different radial positions of the housing and at a second axial location of the housing.