42results about How to "Reduce space charge effects" patented technology

A three section linear or two-dimensional (2D) quadrupole ion trap as a high performance mass spectrometer is described. Mass analysis is performed by ejecting ions radically out a slot formed in one of the rods using the mass selective instability mode of operation. The slot geometry is optimized to yield high ejection efficiencies. Resolution can be controlled by using appropriate end section potentials to control the axial spread of the ion cloud. Multiple detectors can be used for enhancing sensitivity and for enabling enhanced ion analysis techniques in the ion trap.

A multipole ion guide is configured to improve the transmission efficiency of ions which traverse the length of one ion guide and enter either another multipole ion guide such as a quadrupole mass analyzer or a three dimensional ion trap. The ion transfer multipole ion guide radial dimensions are reduced such that the pole assembly and an appropriately shaped exit lens can be positioned within a portion of the internal space defined by the larger radius second multipole ion guide poles. Ions exiting the first ion guide of reduced size find themselves inside the second ion guide close to the centerline. In this manner ions can be efficiently transferred from one ion guide to another, even for those ions with low kinetic energies. In a second embodiment of the invention, the exit region of a multipole ion guide is configured such that the multipole ion guide poles can be extended into a counterbore of a three dimensional ion trap end cap electrode. With this configuration, ions (including those with low kinetic energies) can be transferred into a three dimensional ion trap with increased trapping efficiency.

System and method of gas-cluster ion beam processing is realized by incorporating improved beam and workpiece neutralizing components. Larger GCIB current transport is enabled by low energy electron neutralization of space charge of the GCIB. The larger currents transport greater quantities of gas in the GCIB. A vented faraday cup beam measurement system maintains beam dosimetry accuracy despite the high gas transport load.

In various aspects, the present teachings provide systems and methods for reducing chemical noise in a mass spectrometry instrument that use a neutral chemical reagent and one or more mass filters to reduce interfering chemical background ion signals that are generated by ionization sources of mass spectrometers. In various embodiments, the neutral chemical reagent belongs to the class of organic chemical species containing a disulfide functionality.

An adjustable, low mass-to-charge (m/z) filter is disclosed employing electrospray ionization to block ions associated with unwanted low m/z species from entering the mass spectrometer and contributing their space charge to down-stream ion accumulation steps. The low-mass filter is made by using an adjustable potential energy barrier from the conductance limiting terminal electrode of an electrodynamic ion funnel, which prohibits species with higher ion mobilities from being transmitted. The filter provides a linear voltage adjustment of low-mass filtering from m/z values from about 50 to about 500. Mass filtering above m/z 500 can also be performed; however, higher m/z species are attenuated. The mass filter was evaluated with a liquid chromatography-mass spectrometry analysis of an albumin tryptic digest and resulted in the ability to block low-mass, “background” ions which account for 40-70% of the total ion current from the ESI source during peak elution.

The present invention provides a method of reflecting ions in a multireflection time of flight mass spectrometer comprising providing an ion mirror having a plurality of electrodes, the ion mirror having a cross section with a first, minor axis (Y) and a second, major axis (X) each perpendicular to a longitudinal axis (Z) of the ion mirror which lies generally in the direction of time of flight separation of the ions in the mirror; guiding ions towards the ion mirror; applying a voltage to the electrodes so as to create an electric field which: (a) causes the mean trajectory of the ions to intersect a plane of symmetry of the ion mirror which contains the longitudinal (Z) and major axes (X) of the mirror; (b) causes the ions to reflect in the ion mirror; and (c) causes the ions to exit the ion mirror in a direction such that the mean trajectory of ions passing through the ion mirror has a component of movement in a direction (Y) perpendicular to and diverging from the said plane of symmetry thereof.

An improved FT-ICR Mass Spectrometer has an ion source 10 which generates ions that are transmitted through a series of multipoles 20 to an ion trap 30. Ions are ejected from the trap 30, through a series of lens and multipolar ion guide stages 40–90, and into a measurement cell 100 via an exit/gate lens 110. The measurement cell is mounted in a vacuum chamber 240 and this assembly is slideably moveable into a bore of a superconducting magnet 400 which provides the magnetic filed to cause cyclotron motion of the generated ions in the cell 100. By minimising the distance between the source 10 and cell 100, and by careful alignment of the ion optics, the ions can travel at high energies right up to the front of the measurement cell 100.

The cell 100 extends in the longitudinal direction of the magnet bore and is coaxial with that. The ratio of the sectional area of the magnet bore to the sectional area of the cell volume is small (less than 3). The magnet is asymmetric and is relatively short on the ion injection side. The cell 100 is supported from in front of the cell and electrical contact is from the rear thereof.

Ion implantation systems are provided, comprising a dispersion system located between an ion source and a mass analyzer, that operates to selectively pass an extracted ion beam from the ion source toward the mass analyzer or to direct a dispersed ion beam toward the mass analyzer, where the dispersed ion beam has fewer ions of an undesired mass range than the extracted ion beam.

A method is disclosed comprising: trapping ions in an ion trap (40); applying a first force on the ions within the ion trap in a first direction, said force having a magnitude that is dependent upon the value of a physicochemical property of the ions; applying a second force on these ions in the opposite direction so that the ions separate according to the physicochemical property value as a result of the first and second forces; and then pulsing or driving ions out of one or more regions of the ion trap.

A device for the production of an electron beam with high surface strengths. The device has a cathode component with a convex cathode face with a predetermined radius for extracting the electron beam in such an alignment that a magnetic field or the magnetic field lines thereof, for causing the extraction of the electron beam, is almost collinearly to the convex cathode face.

The invention provides a cleaning method of a wet-type electrostatic dust collector pole plate. A normal pressure dripping spraying cleaning mode or constant pressure overflow spraying cleaning mode or other non-spraying cleaning modes are adopted, the surface tension of water is utilized for overcoming the influence of gravity on water flow, and therefore it is effectively ensured that the pole plate is cleaned completely and efficiently in real time. According to the structure, a water conveying pipe (1), a flow equalizing pipe (2) and the double-layer symmetric corrugated face pole plate (3) are included. Cleaning water is sprayed to the top end of the flow equalizing pipe (2) on the upper portion of the double-layer symmetric corrugated face pole plate (3) in a dripping or overflow spraying mode through the water conveying pipe (1), the flow equalizing pipe (2) equalizes water drops to the two surfaces of the double-layer symmetric corrugated face pole plate (3), a continuous and uniform cleaning water film is used for continuously taking away pollutants collected on the surfaces of the dust collection pole plate, and cleaning of the pole plate is achieved. The characteristics that normal pressure dripping (overflow) spraying, no spraying dead angle, flow distribution balance, the uniform pole plate water film, complete cleaning and the like are adopted, and the cleaning method is small in space-charge effect, stable in electric field operation and efficient, saves energy, and can greatly heighten the pole plate, save floor space and save investment.

The invention discloses a circuit and method for measuring operational amplification bias current and a shielding control unit. The circuit includes an inverted input terminal control unit connected with an inverted input terminal of a to-be-tested operational amplifier; an in-phase input terminal control unit connected with an in-phase input terminal of the to-be-tested operational amplifier; a first auxiliary operation amplification unit whose inverted input terminal is connected with the output terminal of the to-be-tested operational amplifier and whose in-phase input terminal is in grounded connection; a second auxiliary operation amplification unit whose inverted input terminal is connected with the output terminal of the first auxiliary operation amplification unit and whose in-phase input terminal is in grounded connection and whose output terminal outputs electrical signals; a feedback resistor connected between the inverted-phase input terminal of the to-be-tested operationalamplifier and the output terminal of the second auxiliary operational amplification unit so as to form a negative feedback circuit. The invention solves problems of low precision and poor stability in measurement of input bias current of operational amplification device in the prior art; the measurement precision is accurate to picoamp level from nanoamp level and market demands are met.