405 results about "Drift tube" patented technology

A charged particle beam apparatus in which an electrostatic lens is used as a main focusing element to obtain a subminiature high-sensitivity high-resolution SEM, a drift tube for an electron beam is located inside a column between an electron source and a sample, and a detector for secondary electrons is located inside the drift tube. This solves the problem associated with the provision of a secondary electron detector, which heretofore has been a bottleneck in making a subminiature high-resolution SEM column.

Correlation ion mobility spectrometry (CIMS) uses gating modulation and correlation signal processing to improve IMS instrument performance. Closely spaced ion peaks can be resolved by adding discriminating codes to the gate and matched filtering for the received ion current signal, thereby improving sensitivity and resolution of an ion mobility spectrometer. CIMS can be used to improve the signal-to-noise ratio even for transient chemical samples. CIMS is especially advantageous for small geometry IMS drift tubes that can otherwise have poor resolution due to their small size.

A method and apparatus enabling increased sensitivity in ion mobility spectrometry/mass spectrometry instruments which substantially reduces or eliminates the loss of ions in ion mobility spectrometer drift tubes utilizing a device for transmitting ions from an ion source which allows the transmission of ions without significant delay to an hourglass electrodynamic ion funnel at the entrance to the drift tube and/or an internal ion funnel at the exit of the drift tube. An hourglass electrodynamic funnel is formed of at least an entry element, a center element, and an exit element, wherein the aperture of the center element is smaller than the aperture of the entry element and the aperture of the exit elements. Ions generated in a relatively high pressure region by an ion source at the exterior of the hourglass electrodynamic funnel are transmitted to a relatively low pressure region at the entrance of the hourglass funnel through a conductance limiting orifice. Alternating and direct electrical potentials are applied to the elements of the hourglass electrodynamic funnel thereby drawing ions into and through the hourglass electrodynamic funnel thereby introducing relatively large quantities of ions into the drift tube while maintaining the gas pressure and composition at the interior of the drift tube as distinct from those at the entrance of the electrodynamic funnel and allowing a positive gas pressure to be maintained within the drift tube, if desired. An internal ion funnel is provided within the drift tube and is positioned at the exit of said drift tube. The advantage of the internal ion funnel is that ions that are dispersed away from the exit aperture within the drift tube, such as those that are typically lost in conventional drift tubes to any subsequent analysis or measurement, are instead directed through the exit of the drift tube, vastly increasing the amount of ions exiting the drift tube.

In a cluster ion beam irradiation apparatus including an apparatus for measuring size and energy distribution of gas cluster ions by using the time of flight (TOF) mass spectrometry, a unit for applying a retarding voltage is disposed in a stage preceding a TOF measuring instrument including a drift tube and a current measuring instrument. By measuring the size and energy distribution of the gas cluster ions and adjusting ionization conditions, cluster ions having predetermined energy and size are supplied to a work surface. In addition, a product of a pressure in an ion transportation device and an ion transportation length is controlled so as to satisfy the relation P×L≦30/N^2/3/E^1/2 Pa.m, where N is the size of gas cluster ions used for irradiation, and E is kinetic energy (eV) of the gas cluster ions.

A method for multiplexed analysis using ion mobility spectrometer in which the effectiveness and efficiency of the multiplexed method is optimized by automatically adjusting rates of passage of analyte materials through an IMS drift tube during operation of the system. This automatic adjustment is performed by the IMS instrument itself after determining the appropriate levels of adjustment according to the method of the present invention. In one example, the adjustment of the rates of passage for these materials is determined by quantifying the total number of analyte molecules delivered to the ion trap in a preselected period of time, comparing this number to the charge capacity of the ion trap, selecting a gate opening sequence; and implementing the selected gate opening sequence to obtain a preselected rate of analytes within said IMS drift tube.

One embodiment disclosed relates to a scanning electron beam apparatus including an objective lens, scan deflectors, de-scan deflectors, an energy-filter drift tube, and a segmented detector. The objective lens may be an immersion lens configured with a high extraction field so as to preserve azimuthal angle discrimination of the electrons scattered from the specimen surface. The de-scan deflectors may be used to compensate for the scanning of the incident electron beam. The energy-filter drift tube is configured to align the scattered electrons according to polar angles of trajectory from the specimen surface.

A drift tube linear accelerator (linac) that can be used for the acceleration of low energy ion beams. The particles enter the linac at low energy and are accelerated and focused along a straight line in a plurality of resonant accelerating structures interposed by coupling structures up to the desired energy. In the accelerating structures, excited by an H-type resonant electromagnetic field, a plurality of accelerating gaps is provided between drift tubes supported by stems, for instance alternatively horizontally and vertically disposed. A basic module composed of two accelerating structures and an interposed coupling structure, or a modified coupling structure connected to a RF power generator, is if necessary linked to a vacuum system and equipped with one or more quadrupoles.

A portal monitoring system has a cosmic ray charged particle tracker with a plurality of drift cells. The drift cells, which can be for example aluminum drift tubes, can be arranged at least above and below a volume to be scanned to thereby track incoming and outgoing charged particles, such as cosmic ray muons, whilst also detecting gamma rays. The system can selectively detect devices or materials, such as iron, lead, gold and/or tungsten, occupying the volume from multiple scattering of the charged particles passing through the volume and can also detect any radioactive sources occupying the volume from gamma rays emitted therefrom. If necessary, the drift tubes can be sealed to eliminate the need for a gas handling system. The system can be employed to inspect occupied vehicles at border crossings for nuclear threat objects.

An ion mobility spectrometer includes a protective housing. A drift tube having at least one inlet and at least one outlet confines a drift gas. An ion gate is positioned in the drift tube. The ion gate defines a reaction region and a drift region in the drift tube. An ion detector is positioned in the drift tube downstream of the ion gate at an end of the drift region. A helical resistive wire coil is positioned around the drift tube. A power supply generates an electric field in the helical resistive wire coil that rapidly controls the temperature of the drift gas.

The present invention relates to a device for separation and characterization of gas-phase ions. The device incorporates an ion source, a field asymmetric waveform ion mobility spectrometry (FAIMS) analyzer, an ion mobility spectrometry (IMS) drift tube, and an ion detector. In one aspect of the invention, FAIMS operating voltages are electrically floated on top of the IMS drift voltage. In the other aspect, the FAIMS/IMS interface is implemented employing an electrodynamic ion funnel, including in particular an hourglass ion funnel. The present invention improves the efficiency (peak capacity) and sensitivity of gas-phase separations; the online FAIMS/IMS coupling creates a fundamentally novel two-dimensional gas-phase separation technology with high peak capacity, specificity, and exceptional throughput.

A neutron tube or generator is based on a RF driven plasma ion source having a quartz or other chamber surrounded by an external RF antenna. A deuterium or mixed deuterium/tritium (or even just a tritium) plasma is generated in the chamber and D or D/T (or T) ions are extracted from the plasma. A neutron generating target is positioned so that the ion beam is incident thereon and loads the target. Incident ions cause D-D or D-T (or T-T) reactions which generate neutrons. Various embodiments differ primarily in size of the chamber and position and shape of the neutron generating target. Some neutron generators are small enough for implantation in the body. The target may be at the end of a catheter-like drift tube. The target may have a tapered or conical surface to increase target surface area.

An RF device comprising a plurality of drift tubes, each drift tube having a plurality of gaps defining resonant cavities, is immersed in an axial magnetic field. RF energy is introduced at an input RF port at one of these resonant cavities and collected at an output RF port at a different RF cavity. A plurality of electron beams passes through these drift tubes, and each electron beam has an individual magnetic shaping applied which enables confined beam transport through the drift tubes.

An in-situ ion sensor is disclosed for monitoring ion species in a plasma chamber. The ion sensor may comprise: a drift tube; an extractor electrode and a plurality of electrostatic lenses disposed at a first end of the drift tube, wherein the extractor electrode is biased to attract ions from a plasma in the plasma chamber, and wherein the plurality of electrostatic lenses cause at least one portion of the attracted ions to enter the drift tube and drift towards a second end of the drift tube within a limited divergence angle; an ion detector disposed at the second end of the drift tube, wherein the ion detector detects arrival times associated with the at least one portion of the attracted ions; and a housing for the extractor, the plurality of electrostatic lenses, the drift tube, and the ion detector, wherein the housing accommodates differential pumping between the ion sensor and the plasma chamber.

The invention discloses a method for rapidly screening 40 prohibited antibiotics in cosmetics. The method comprises the following steps: (1) manufacturing an in-situ spray ionization device: producing a borosilicate glass capillary and assembling an in-situ spray ionization device; (2) ion mobility spectrometry detection: dipping a metal micro electrode into a cosmetic sample, then inserting the metal micro electrode into a borosilicate glass capillary, which is filled with methanol in advance, placing the capillary on the front end of the electrospray ionization (ESI) injection port of an ion mobility spectrometry instrument, setting the parameters of the ion mobility spectrometry instrument, ionizing the sample, separating the ionized sample in a drift tube, detecting the sample by a Faraday cup detector to obtain a corresponding experiment map. If the sample detected by the ion mobility spectrometry contains prohibited antibiotics, the sample can be further detected by high performance liquid chromatography-mass spectrum (HPLC-MS) or mass spectrum. The provided method is accurate and reliable, on the basis that the detected data is precise, the detection cost is largely reduced, and the detection efficiency is improved.

A focused droplet nebulizer of the invention produces substantially uniform droplets of a predetermined size. Droplets are pushed out through a small outlet orifice by the contraction of a chamber. The droplets can be carried on a substantially non-divergent path in a drift tube. A piezo membrane micro pump acts in response to an electrical control signal to force a droplet out of the outlet orifice. The nebulizer can operate at frequencies permitting a stream of individual droplets of the predetermined size to be sent along the substantially non-divergent path in the drift tube in a preferred embodiment ELSD device.

A sensor and detection methods are provided for detecting nitric oxides (NOx) in an exhaust gas based upon ion mobility spectrometry (IMS) technique. An ionization chamber having an interior electrically conductive shell receives exhaust gas. A spark electrode having a needle tip extends into the ionization chamber. A shutter grid is coupled between the ionization chamber and an ion drift tube. A substantially continuous spark discharge is established between the electrically conductive shell and the needle tip of the spark electrode for ionization of the exhaust gas. Negative NO₂ ions are kept inside the chamber by biasing the electrically conductive shell and the shutter grid at a negative voltage. Then a positive pulse is applied to the shutter grid to cause the shutter to open for negative NO₂ ions to exit into the ion drift tube. The IMS sensor is small-sized, low-cost, robust, and reliable.

The invention discloses a medical proton linear accelerator. The medical proton linear accelerator comprises an ECR ion source, an RFQ accelerator, an SDTL and a traveling wave proton accelerator which are connected in sequence; a separated type drift tube linear accelerator, namely SDTL, is adopted in an intermediate energy acceleration section; the traveling wave proton accelerator is adopted in a high energy acceleration section, so that the medical proton linear accelerator is more compact in structure and smaller in occupied space; the energy of the emitted proton beams can be continuously adjustable within a rang of 70-250MeV, so that the requirement of adjusting energy of different beams in a patient body due to different tumor positions in tumor treatment can be satisfied; in addition, the SDTL and the traveling wave proton accelerator both adopt a structure which is formed by multiple sections connected in sequence, and can be constructed in different periods and different stages, so as to satisfy requirement on proton energy of different hospitals; and energy upgrading also can be performed according to treatment demands in post periods.