131results about "Gas pressure measurement discharge tubes" patented technology

A small-sized charged particle beam apparatus capable of maintaining high vacuum even during emission of an electron beam is provided. A nonevaporative getter pump is placed upstream of differential pumping of an electron optical system of the charged particle beam apparatus, and a minimum number of ion pumps are placed downstream, so that both the pumps are used in combination. Further, by mounting a detachable coil on an electron gun part, the inside of a column can be maintained under high vacuum with a degree of vacuum in the order of 10−8 Pa.

A small-sized charged particle beam apparatus capable of maintaining high vacuum even during emission of an electron beam is provided. A nonevaporative getter pump is placed upstream of differential pumping of an electron optical system of the charged particle beam apparatus, and a minimum number of ion pumps are placed downstream, so that both the pumps are used in combination. Further, by mounting a detachable coil on an electron gun part, the inside of a column can be maintained under high vacuum with a degree of vacuum in the order of 10−8 Pa.

A cold cathode ionization vacuum gauge includes an extended anode electrode and a cathode electrode surrounding the anode electrode along its length and forming a discharge space between the anode electrode and the cathode electrode. The vacuum gauge further includes an electrically conductive guard ring electrode interposed between the cathode electrode and the anode electrode about a base of the anode electrode to collect leakage electrical current, and a discharge starter device disposed over and electrically connected with the guard ring electrode, the starter device having a plurality of tips directed toward the anode and forming a gap between the tips and the anode.

The invention provides, inter alia, methods of extracting an analyte from a solution comprising the steps of: passing a solution containing an analyte through an extraction channel having a solid phase extraction surface, whereby analyte adsorbs to the extraction surface of said extraction channel; and eluting the analyte by passing a desorption solution through the channel, wherein the method includes a step wherein a multiple-pass solution is passed through at least some substantial portion of the extraction channel at least twice. Non-limiting examples multiple-pass solutions include a solution containing an analyte, a wash solution and / or a desorption solution.

An ionization vacuum gauge which has at least three electrodes of a grid (2), an electron source (3) and an ion collector (1) in a vacuum vessel (4) connected in communication with a vacuum apparatus, oscillates electrons emitted from the electron source (3) within and outside of the grid (2), ionizes gas molecules flying into the grid (2) by the oscillated electrons, supplements the ionized ions by the ion collector (1) to convert into a current signal, and measures a gas molecular density (pressure) in the vacuum apparatus according to the obtained current intensity, wherein the ion collector (1) is provided with heating means for heating the ion collector.

The invention provides, inter alia, methods of extracting an analyte from a solution comprising the steps of: passing a solution containing an analyte through an extraction channel having a solid phase extraction surface, whereby analyte adsorbs to the extraction surface of said extraction channel; and eluting the analyte by passing a desorption solution through the channel, wherein the method includes a step wherein a multiple-pass solution is passed through at least some substantial portion of the extraction channel at least twice. Non-limiting examples multiple-pass solutions include a solution containing an analyte, a wash solution and / or a desorption solution.

Respirable particles with diameters on the order of 0.05 to 10 microns entrained in an air stream. are concentrated in an aerodynamic lens (FIG. 2) for separation from the air steam. The entire structure is made by microfabrication techniques, such as silicon micro-machining which enables arrays of precisely aligned slit lenses to be made on a silicon chip. At a Reynolds number of 800, a slit 25 microns wide by 1 mm tall will pass a flow of only 0.28 liters per minute, but arrays of lenses (FIG. 4), stacked in parallel banks, multiplies the available flow rate. Placing a skimmer (27) at the exit of each silicon micro-machined lens in the assembly and connecting the skimmer channels in chimneys (55), allows the bulk of the gas flow to be stripped off while allowing the concentrated particle stream to pass into a region of much lower flow rate, thereby producing a highly concentrated aerosol in the low velocity stream.

An electron-emitting cathode consists of an electrically conducting emitter layer attached to a side wall which consists of stainless steel and a gate which is fixed at a mall distance inside a concave emitter surface of the emitter layer. The cathode surrounds a reaction area containing a cylindrical grid-like anode and a central ion collector which consists of a straight axial filament. An ion collector current reflecting the density of the gas in the reaction region is measured by a current meter while a gate voltage is kept between the ground voltage of the emitter layer and a higher anode voltage and is regulated in such a way that an anode current is kept constant. The emitter layer may consists of carbon nanotubes, diamond-like carbon, a metal or a mixture of metals or a semiconductor material, e.g., silicon which may be coated, e.g., with carbide or molybdenum. The emitter surface can, however, also be a portion of the inside surface of the side wall roughened by, e.g., chemical etching. The gate may be a grid or it may be made up of patches of metal film covering spacers distributed over the emitter area or a metal film covering an electron permeable layer placed on the emitter surface.

An ionisation vacuum gauge for measuring the residual pressure of a gaseous material remaining in a container (10), more particularly after operation of a vacuum pump comprises an electron-emitting cathode (31) made by exploiting the nanotube technology, a grid (13; 33; 133; 133′) for accelerating the electrons emitted by the cathode, and a plate (15; 35) collecting the ions and / or the ionised positive molecules of the gas. Measuring the plate current by a galvanometer allows for determining the value of the residual pressure inside the container.

An ionization gauge that eliminates a hot cathode or filament, but maintains a level of precision of gas density measurements approaching that of a hot cathode ionization gauge. The ionization gauge includes a collector electrode disposed in an ionization volume, an electron source without a heated cathode, and an electrostatic shutter that regulates the flow of electrons between the electron source and the ionization volume. The electrostatic shutter controls the flow of electrons based on feedback from an anode defining the ionization volume. The electron source can be a Penning or glow discharge ionization gauge.

An ionization gauge includes an electron generator array that includes a microchannel plate that includes an electron generating portion of the microchannel plate comprising a source for generating seed electrons and an electron multiplier portion of the microchannel plate, responsive to the seed electrons generated by the electron generating portion, that multiplies the electrons. The ionization gauge includes an ionization volume in which the electrons impact a gaseous species, and a collector electrode for collecting ions formed by the impact between the electrons and gas species. The collector electrode can be surrounded by the anode, or the ionization gauge can be formed with multiple collector electrodes. The source of electrons can provide for a spontaneous emission of electrons, where the electrons are multiplied in a cascade.

Accurate mass measurement is carried out for product ions of a sample. A method for accurate mass determination of ions with Trap-TOF / μs includes steps of generating ions of an analyte sample and a standard material; introducing the ions of the analyte sample and the standard material together into an ion trap to trap them; selecting a precursor ion from the ions of the analyte sample to leave the precursor ion and a standard material ion in the ion trap and eliminate other ions; exciting and dissociating the precursor ion to generate product ions; ejecting the precursor ion, its product ions, and the standard material ion trapped in the ion trap to introduce these ions into the TOF mass spectrometer; and measuring a mass spectrum with the TOF mass spectrometer, where correction for accurate masses of the product ions is carried out based on the standard material ion measured.

An ionization gauge to measure pressure and to reduce sputtering yields includes at least one electron source that generates electrons. The ionization gauge also includes a collector electrode that collects ions formed by the collisions between the electrons and gas molecules. The ionization gauge also includes an anode. An anode bias voltage relative to a bias voltage of a collector electrode is configured to switch at a predetermined pressure to decrease a yield of sputtering collisions.

An ionization gauge for isolating an electron source from gas molecules includes the electron source for generating electrons, a collector electrode for collecting ions formed by the impact between the electrons and gas molecules, and an electron window which isolates the electron source from the gas molecules. The ionization gauge can have an anode which defines an anode volume and retains the electrons in a region of the anode. The ionization gauge can have a plurality of electron sources and / or collector electrodes. The collector electrode(s) can be located within the anode volume or outside the anode volume. The ionization gauge can have a mass filter for separating the ions based on mass-to-charge ratio. The ionization gauge can be a Bayard-Alpert type that measures pressure or a residual gas analyzer that determines a gas type.

Shields for feedthrough pin insulators of a hot cathode ionization gauge are provided to increase the operational lifetime of the ionization gauge in harmful process environments. Various shield materials, designs, and configurations may be employed depending on the gauge design and other factors. In one embodiment, the shields may include apertures through which to insert feedthrough pins and spacers to provide an optimal distance between the shields and the feedthrough pin insulators before the shields are attached to the gauge. The shields may further include tabs used to attach the shields to components of the gauge, such as the gauge's feedthrough pins. Through use of example embodiments of the insulator shields, the life of the ionization gauge is extended by preventing gaseous products from a process in a vacuum chamber or material sputtered from the ionization gauge from depositing on the feedthrough pin insulators and causing electrical leakage from the gauge's electrodes.

A cold cathode ionization vacuum gauge includes an extended anode electrode and a cathode electrode surrounding the anode electrode along its length and forming a discharge space between the anode electrode and the cathode electrode. The vacuum gauge further includes an electrically conductive guard ring electrode interposed between the cathode electrode and the anode electrode about a base of the anode electrode to collect leakage electrical current, and a discharge starter device disposed over and electrically connected with the guard ring electrode, the starter device having a plurality of tips directed toward the anode and forming a gap between the tips and the anode.

An ionization vacuum gauge which has at least three electrodes of a grid (2), an electron source (3) and an ion collector (1) in a vacuum vessel (4) connected in communication with a vacuum apparatus, oscillates electrons emitted front the electron source (3) within and outside of the grid (2), ionizes gas molecules flying into the grid (2) by the oscillated electrons, supplements the ionized ions by the ion collector (1) to convert into a current signal, and measures a gas molecular density (pressure) in the vacuum apparatus according to the obtained current intensity, wherein the ion collector (1) is provided with a heating device for heating the ion collector.