Abstract: The invention provides a cathode system for an Electron Ionization (EI) source comprising a filament and current supply posts, the current supply posts dividing the filament into segments and each current supply post supplying or returning the current for at least two segments of the filament. Each filament segment is connected, for instance by spot welding, to the supply posts delivering the heating current. The filament segments may be arranged in a row, or substantially parallel to each other. Filament segments arranged in a row may form a closed loop, for instance, a ring. Other embodiments encompass the filament shape of a helical coil.

Abstract: The invention provides a cathode system for an Electron Ionization (EI) source comprising a filament and current supply posts, the current supply posts dividing the filament into segments and each current supply post supplying or returning the current for at least two segments of the filament. Each filament segment is connected, for instance by spot welding, to the supply posts delivering the heating current. The filament segments may be arranged in a row, or substantially parallel to each other. Filament segments arranged in a row may form a closed loop, for instance, a ring. Other embodiments encompass the filament shape of a helical coil.

Abstract: An atmospheric pressure ion source, employing the principle of electrospray ionization, chemical ionization, or photo-ionization, comprises a spray probe for spraying a liquid into an ionization chamber and has an exhaust port through which residual spray mist and waste gas, such as evaporated solvent, are extracted. The ion source further comprises an exhaust system comprising a conduit which is connected to the exhaust port. The conduit has a transition from a first cross-section to a second cross section at a point downstream of the exhaust port wherein the second cross section is reduced in relation to the first cross section. Gas is injected via a gas injector into the conduit in a region of the transition to create a low pressure region that removes unwanted material from the chamber.

Abstract: An assembly for use in an electrospray ion source includes a capillary for guiding a flow of liquid generally containing analyte(s) of interest, which is to be electrosprayed into an ionization chamber, a first tube at least partially encasing the capillary such that a first conduit for guiding a first heatable gas is created proximate the capillary and a hollow member that has an internal evacuated space and is located at the outer circumference of the capillary such that heat transfer from the first heatable gas flowing proximate the capillary to the liquid in the capillary is impeded. The assembly provides a simple and lean/compact way of preventing excessive heat transfer to the liquid in the capillary of an electrospray ion source.

Abstract: An ion optics assembly is formed by four quarter-circular profile elements, all of which are attach to the same reference plate. Consequently, all four elements remain aligned to the same reference plate. The four elements form a quarter-circular channel with quarter-circular quad electrodes. The quad electrodes receive electrical potential to form the field required to focus and maintain the ions at the center of the channel. Quarter-circular insulators are provided on all sides of the channel so as to seal the channel over its length from the interior of the mass spectrometer. A heater is provided at the entrance to the ion transfer optics, to prevent accumulation of ions on the poles. A thermal break is provided in the quad, so as to enable maintaining the front of the quad heated and the rest of the quad cooler.

Abstract: An atmospheric pressure ion source, employing the principle of electrospray ionization, chemical ionization, or photo-ionization, comprises a spray probe for spraying a liquid into an ionization chamber and has an exhaust port through which residual spray mist and waste gas, such as evaporated solvent, are extracted. The ion source further comprises an exhaust system comprising a conduit which is connected to the exhaust port. The conduit has a transition from a first cross-section to a second cross section at a point downstream of the exhaust port wherein the second cross section is reduced in relation to the first cross section. Gas is injected via a gas injector into the conduit in a region of the transition to create a low pressure region that removes unwanted material from the chamber.

Abstract: Methods and systems to compensate for distortions created by dynamic voltage applied to an electron multiplier used in mass spectrometry. An electron multiplier has a cathode end accepting ion flow, an opposite emitter end and an interior surface. The electron multiplier produces an electron output from ions colliding with the interior surface. A variable power supply has a voltage output coupled to the cathode end and the emitter end of the electron multiplier. The voltage output changes dynamically to adjust the electron output from the electron multiplier. An anode is located in proximity to the electron multiplier. An electrometer is coupled to the anode in proximity to the electron multiplier to measure the current generated by the electron output. A low pass filter circuit is coupled to the emitter end to the ground of the electrometer to attenuate emitter voltage changes. A bias circuit is coupled to the emitter end to stabilize emitter to anode voltage difference.

Abstract: An assembly for use in an electrospray ion source includes a capillary for guiding a flow of liquid generally containing analyte(s) of interest, which is to be electrosprayed into an ionization chamber, a first tube at least partially encasing the capillary such that a first conduit for guiding a first heatable gas is created proximate the capillary and a hollow member that has an internal evacuated space and is located at the outer circumference of the capillary such that heat transfer from the first heatable gas flowing proximate the capillary to the liquid in the capillary is impeded. The assembly provides a simple and lean/compact way of preventing excessive heat transfer to the liquid in the capillary of an electrospray ion source.

Abstract: A multipole rod assembly, such as used as mass analyzer, is fabricated using rods adhesively attached to shoes, which are then attached to isolation rings. A fixture is used in conjunction with precision-made spacers to precisely assemble the ion mass analyzer. The rods and shoes can be made of metal, while the isolation rings are preferably made of insulator, such as ceramic. The shoes and isolation rings need not be made to high precision, as the spacer ensures high accuracy in alignment and symmetry of the rods. Consequently, the rods are the only precision machined parts in the ion mass analyzer assembly.

Abstract: An ion collision cell is fabricated by four semi-circular profile elements, all of which are attach to the same reference plate. Consequently, all four elements remain aligned to the same reference plate. The four elements form a semi-circular channel with a semi-circular quad electrodes. The quad electrodes receive electrical potential to form the field required to focus and maintain the ions at the center of the channel. semi-circular insulators are provided on all sides of the channel so as to seal the channel over its length from the interior of the mass spectrometer.

Abstract: An ion optics assembly is formed by four quarter-circular profile elements, all of which are attach to the same reference plate. Consequently, all four elements remain aligned to the same reference plate. The four elements form a quarter-circular channel with quarter-circular quad electrodes. The quad electrodes receive electrical potential to form the field required to focus and maintain the ions at the center of the channel. Quarter-circular insulators are provided on all sides of the channel so as to seal the channel over its length from the interior of the mass spectrometer. A heater is provided at the entrance to the ion transfer optics, to prevent accumulation of ions on the poles. A thermal break is provided in the quad, so as to enable maintaining the front of the quad heated and the rest of the quad cooler.

Abstract: Methods and systems to compensate for distortions created by dynamic voltage applied to an electron multiplier used in mass spectrometry. An electron multiplier has a cathode end accepting ion flow, an opposite emitter end and an interior surface. The electron multiplier produces an electron output from ions colliding with the interior surface. A variable power supply has a voltage output coupled to the cathode end and the emitter end of the electron multiplier. The voltage output changes dynamically to adjust the electron output from the electron multiplier. An anode is located in proximity to the electron multiplier. An electrometer is coupled to the anode in proximity to the electron multiplier to measure the current generated by the electron output. A low pass filter circuit is coupled to the emitter end to the ground of the electrometer to attenuate emitter voltage changes. A bias circuit is coupled to the emitter end to stabilize emitter to anode voltage difference.

Abstract: A multipole rod assembly, such as used as mass analyzer, is fabricated using rods adhesively attached to shoes, which are then attached to isolation rings. A fixture is used in conjunction with precision-made spacers to precisely assemble the ion mass analyzer. The rods and shoes can be made of metal, while the isolation rings are preferably made of insulator, such as ceramic. The shoes and isolation rings need not be made to high precision, as the spacer ensures high accuracy in alignment and symmetry of the rods. Consequently, the rods are the only precision machined parts in the ion mass analyzer assembly.

Abstract: An ion collision cell is fabricated by four semi-circular profile elements, all of which are attach to the same reference plate. Consequently, all four elements remain aligned to the same reference plate. The four elements form a semi-circular channel with a semi-circular quad electrodes. The quad electrodes receive electrical potential to form the field required to focus and maintain the ions at the center of the channel. semi-circular insulators are provided on all sides of the channel so as to seal the channel over its length from the interior of the mass spectrometer.

Abstract: A method and accompanying apparatus for automatically extending the linear dynamic absorbance range of absorbance detectors including multi-lightpath flow cells. The absorbance of a reference beam in a relatively short reference path is multiplied by a ratio of the absorbance of a sample beam in a relatively long sample path to the reference path absorbance in developing a relative absorbance for the sample path beyond its linear dynamic range.

Abstract: A compact high performance absorbance detector including a flashlamp light source and folded optics system with ruled grating reflecting beam splitter for minimizing flash to flash angular pattern and spectral variations of the flashlamp.

Abstract: A liquid chromatography system mixing chamber having a motor-driven magnet situated beside an interior compartment wherein one or more stirring magnets are disposed for mixing solvents fed to the mixing chamber by appropriate metering pumps. A fitting is provided having an expandable ring seal, the fitting being insertable into the interior compartment for effecting a high-pressure seal for preventing leakage of the solvent mixture, while enabling access to the interior of the mixing chamber for maintenance purposes without the need for a tool.

Abstract: A system for depassivating a passivated lithium battery in a battery powered microprocessor controlled device by successively and momentarily drawing current from the passivated battery after a turn on of the device while monitoring the power delivery condition of the battery under a load condition until salt crystals on an electrode of the battery are dissipated and the battery is returned to a useful power delivery condition or until a predetermined period of time has elapsed without the battery returning to the useful power delivery condition, whichever is sooner.

Abstract: A dashpot piston mounted in a closed chamber is coupled by an axially movable shaft to a pipette piston to regulate return movement of the pipette piston within a pipette cylinder to draw fluid into the cylinder. The dashpot shaft is movable within limits relative to the dashpot piston to accommodate a blow-out of residual fluid from the pipette by the shaft driving the pipette piston beyond a home position to blow residual fluid from the pipette cylinder. An air inlet port in the bottom of the chamber allows air to be drawn into the chamber with upward movement of the dashpot piston while a valve adjacent to the air inlet port opens in response to downward movement of the dashpot piston to exit air from the chamber. Control of the relative sizes of the air inlet port and valve outlet regulates the relative rates of upward and downward piston movement in the cylinder.

Abstract: A decoder for pulse width modulated (PWM) signals comprising an integrator and a sample-and-hold circuit wherein the sample-and-hold output signal is fed back to the input of the integrator. No periodic initialization of the integrator is required. The gains of the integrator and sample-and-hold circuits and the capacitance of the integrator capacitor affect only the settling time of the decoder, not the value to which the decoder output ultimately settles.