Abstract: Apparatus for analyzing components in a mixture by the steps of introducing the mixture into the ion source of a mass spectrometer, ionizing some of the individual molecules representative of the mixture, using the mass spectrometer to select a beam of ions of a single ion mass which may be characteristic of a target compound in the mixture, passing the resultant single-mass beam of ions through a gas-filled collision chamber, and then, using a second mass spectrometer, determining the mass spectrum of the collision fragment ions to confirm the identity of the target compound, and by measuring the intensity of all or part of the mass spectrum, determine its concentration or amount in the original sample mixture. The same apparatus is suitable for fundamental measurements of the collision processes, which in addition to fragmentation include ion molecule reactions, charge changing collisions, and others, in addition to analytical applications.

Abstract: A method and apparatus for monitoring particulates which are borne by a surrounding gaseous medium, such as found in smokestack or the like, through interception of the particulates by a hot filament having a bias potential in the range of about 100 to 1000 volts whereupon each particulate decomposes into a burst of ions which is collected by a nearby electrode at ground potential, by counting those bursts which produce a predetermined total charge and, at the same time, measuring the DC electric current produced by the bursts and other ion exchange between the hot filament and the electrode. The filament operates at a temperature level wherein infrared and visible radiations are emitted, such radiations being monitored by a phototransistor which receives the radiations.

Abstract: A method and apparatus for monitoring particulates which are borne by a surrounding gaseous medium, such as found in smokestacks or the like, through interception of the particulates by a hot filament having a bias potential in the range of about 100 to 1000 volts whereupon each particulate decomposes into a burst of ions which is collected by a nearby electrode at ground potential, by counting those bursts which produce a predetermined total charge and, at the same time, measuring the DC electric current produced by the bursts and other ion exchange between the hot filament and the electrode. The filament operates at a temperature level wherein infrared and visible radiations are emitted, such radiations being monitored by a phototransistor which receives the radiations.

Abstract: The measurement of a dc current from ions produced in a surface ionization detector for particulates in combination with simultaneous particulate counting to differentiate between particulates above or below a predetermined size and total particulates present thus determining whether a given aerosol consists primarily of large particulates or very small particulates and providing general information about the particle size in an aerosol. The dc current measurement further provides surface ionization detection of particulates at densities which overload circuitry for pulse counting, whereby the dynamic range of the instrument is extended.

Abstract: The selection of charged particles having a narrow band of kinetic energies from emitted charged particles having a wider band of kinetic energies by repulsing those particles having energies less than the lower energy in the transmitted energy band through means of a similarly charged barrier and in the same device insufficiently deflecting the higher energy particles which pass the barrier by a field provided beyond the barrier whereby they fail to pass through an exit aperture. Thus only particles having energies within the desired band pass through an exit aperture which is disposed on the opposite side of the barrier. The pass band of energies is variable in width and location, and the width of the band may be independent or a function of the energy in the band depending on the potentials applied to the barrier and the strength of the field beyond the barrier.

Abstract: Method and apparatus for the detection of electronegative chemical species in gas flows, such as exist from gas chromatographs, by sampling the detector volume via an aperture connecting to a lower pressure region containing apparatus to collect and measure the negative ion current. Because of the free diffusion of electrons in the region of the aperture, as opposed to ambipolar diffusion in a conventional electron capture detector volume, the electrons are largely removed from the negatively charged components in the gas stream there. Similarly, positive ion current may be measured, thus extending the analytical capability of the invention to classes of chemical species normally not yielding a response in electron capture detectors.

Abstract: Electric fields for electrostatic optics for focusing or otherwise controlling beams of ions, electrons and charged particles in general produced by surface current distributions which flow on appropriately shaped and located resistive elements from electrical power sources of appropriate voltage connected to two or more points or regions of the resistive surfaces; the resulting electric fields in the proximity of the current carrying surfaces are parallel to these surfaces. Useful electric field configurations may be produced which are inconvenient or impossible to produce by the prior art using surface charge distributions. New and improved analyzers of "concentric hemisphere" and "parallel plate" types are specifically utilized for ion kinetic energy selection prior to measurement of the mass-to-charge ratio of secondary ions produced by primary ion bombardment of surfaces.

Abstract: A method and apparatus for mass spectrometry employing tandem chemical ionization (CI) and electron impact (EI) ionization chambers with independent ionizing electron sources, both CI and EI ions being produced simultaneously. Through electronic shuttering either the CI or EI ions may be transmitted to the mass spectrometer while the ions of the other type are dispersed and rejected. The shuttering being accomplished very rapidly relative to the mass scan rate, which is in turn fast with respect to temporal variations in sample material composition. The two interwoven ion sequences are demultiplexed and smoothed into independent and effective simultaneous CI and EI mass spectrum channels.

Abstract: A hot surface detector for heavy ions following their separation on the basis of charge-to-mass ratio. Upon striking the hot surface, the heavy ions decompose and give up their lighter constituent and/or impurity atoms and molecules to the surface. Those constituent and/or impurity atoms and molecules with ionization potentials or electron affinities comparable to the work function of the hot surface become surface ionized and are emitted from the surface as a burst of either positive or negative ions which are then detected by conventional means, including detection at an electrode, by an electron multiplier or by a mass spectrometric detector for light ions. Where negative ions are to be detected, a magnetic field is applied to prevent electrons from the hot surface from reaching the detector.

Abstract: Methods and apparatus for spatially separating AC and DC electric fringe fields near the ends of quadrupole mass filters which involve use of materials with electric properties that function as dielectrics to the AC fields and as conductors to the DC fields. Devices constructed of such materials shield against DC fringe fields, but not against AC fringe fields. Such devices include a small shield in the form of a tube or other appropriate configuration disposed coaxially with the axis of the mass filter at either or both ends thereof. A good dielectric is used as the supporting structure and a thin conductive or semi-conductive layer is applied thereto which functions as the shield.

Abstract: Application of dc potentials of values other than ground to materials which appear as conductors to dc and low frequency ac electric fields and as dielectrics to high frequency ac electric fields in order to compensate for changes of potential due to ion and electron currents reaching the material and/or to provide for improved focusing of the ions, particularly with large ion currents, into a quadrupole mass filter.