Abstract: An method of, and an apparatus for, collecting a sample of a substance of interest, utilizes an apparatus having a device for collecting a vapor sample and a device for retaining a substrate. A substrate, having a working portion and a mounting portion, is mounted by the mounting portion of the substrate, whereby the working portion of the substrate is exposed for use. The apparatus so that the working portion of the substrate traverses surfaces of interest, to collect a particulate sample. A device for sampling vapor is operated to obtain a vapor sample. The vapor and particulate samples collected are analyzed.

Abstract: An method of, and an apparatus for, collecting a sample of a substance of interest, utilizes an apparatus having a device for collecting a vapor sample and a device for retaining a substrate. A substrate, having a working portion and a mounting portion, is mounted by the mounting portion of the substrate, whereby the working portion of the substrate is exposed for use. The apparatus so that the working portion of the substrate traverses surfaces of interest, to collect a particulate sample. A device for sampling vapor is operated to obtain a vapor sample. The vapor and particulate samples collected are analyzed.

Abstract: A walk-through portal or other enclosure is provided for at least one of detection of a predetermined substance on a subject and decontamination of a subject from a predetermined substance, the subject being either a person or, for other type of enclosure, an object, such as a suitcase. The walk-through portal defines an examination zone and can be substantially open on at least one side, to permit a subject readily to enter and to exit the examination zone. A closure closes off the examination zone from the exterior. An inlet into the examination zone and an outlet from the examination zone permit air or other gas to flow through it, and this is pumped by a pump, so as to entrain at least one of vapors and particulates from such substance. At least part of the exhaust through the outlet can be passed to an analyzer, such as an IMS, to detect substances of interest.

Abstract: A method is provided for monitoring the concentration of water vapor in an ion mobility spectrometer which measures the drift time of a selected ion, having a tendency to form clusters of water molecules. As these clusters are formed, the drift time of the ion varies, and by monitoring this variation in drift time, a measure of the concentration of water vapor can be made. If this exceeds a certain level, a warning can be given and/or the instrument disabled. Preferably, a comparison is made between two different ions, one having at least a moderate tendency to form clusters with water molecules, and the other having a weak tendency to form such clusters. By comparing the two drift times, a relatively accurate determination of water concentration can be made, and this can automatically allow for variations of drift times due to other causes.

Abstract: A hand held sampling method is carried out using apparatus have a handle, a head connected to the handle and a mechanism for retaining a substrate on the head. The substrate is preferably a sheet-form flexible substrate which is mounted so as to present a collection portion thereof for collection of a sample. The substrate is preferably of a dimension so as to be readily fitted into the inlet portion of an analyzer. The apparatus is manipulated so that the collection portion of the substrate traverses surfaces of interest. The substrate is then removed and placed at the inlet of an analyzer for desorption of a sample. The apparatus enables an area to be sampled quickly and efficiently, while keeping a user's hands away from the surface, and this enables otherwise inaccessible areas to be sampled. It does not require any intermediate transfer steps, transferring a sample from a collection media to another substrate for subsequent analysis.

Abstract: A hand held sampling apparatus and method are provided. The apparatus has a handle, a head connected to the handle and a mechanism for retaining a substrate on the head. The substrate is preferably a sheet-form flexible substrate which is mounted so as to present a collection portion thereof for collection of a sample. The substrate is preferably of a dimension so as to be readily fitted into the inlet portion of an analyzer. The apparatus enables an area to be sampled quickly and efficiently, while keeping a user's hands away from the surface, and this enables otherwise inaccessible areas to be sampled. It does not require any intermediate transfer steps, transferring a sample from a collection media to another substrate for subsequent analysis.

Abstract: The gas pressure in an ion mobility spectrometer is controlled to maintain near-constant pressure in the drift region by adjusting gas flows in response to a pressure transducer output. The pressure in the system may be referenced to ambient pressure. The increase in pressure stability achieved permits the expected drift times of target analytes to be determined much more accurately than otherwise, and thereby allows more specific detection parameters to be used. This in turn results in a significantly improved false alarm rate for the device.

Abstract: There is provided an assembly for preferentially separating and collecting particles that are gathered from the surface of an article such as an item of baggage. The assembly features an impactor and a suction anvil that is displaceable from a collection medium. The anvil is displaceable from the collection medium so that the medium may be removed and analyzed for traces of substances such as explosives or narcotics. There is also provided, in combination with the assembly, a vacuum head and conduit for gathering the particles and a suction unit for creating the suction force. The collection medium containing collected particles is moved from the impactor to an analyzer by a stage movement device. The analyzer includes an analysis unit, such as an Ion Mobility Spectrometer, and a displaceable heater anvil.

Abstract: An ion mobility spectrometer for detecting substances such as narcotics and explosives, has inlets for a sample gas and a drift gas. The gas can be ambient air, bottled air, or another gas source. To ensure accuracy and prevent drifting of analyte peaks, the air is dried. A two stage dryer is provided comprising a first dryer, preferably a dryer which chills the air and removes water by condensation. This removes the bulk of the water. The second dryer includes a suitable absorbent, and reduces the water content to around 1-10 .mu.g/L, i.e. a level which will not substantially affect the performance of the IMS apparatus. The first dryer substantially reduces the load on the second dryer, and enables an extended period of use before the absorbent material in the second dryer either needs to be replaced or regenerated. The increased stability of calibrant and analyte peak positions allows detection windows to be narrowed, resulting in significantly lower false alarm rates.

Abstract: According to the method, a primary electromagnetic field, defined by a waveform of known shape and containing a plurality of frequency components, is directed towards a target zone. Signals are received in the vicinity of the target zone which are attributable to eddy currents in conductors present in the target zone and direct coupling with the primary field. A reference signal having a complex waveform similar to that of the primary field is generated artificially and the reference signal is compared with the received signals in a digital computer in such a manner as to minimize the amount of signal present in the received signal which is attributable to direct coupling with the primary field. The resulting received signal may then be correlated with a plurality of stored reference waveforms in order to obtain the best fit.

Abstract: A sample of material to be analyzed is applied in a thin layer to a substrate such as an elongated tape and then is illuminated by a laser beam of such wavelength and power that at least a portion of the sample is vaporized. The substrate is non-absorptive at the laser wavelength and therefore is unaffected by the laser beam. The vaporized matter is removed from the region at which vaporization takes place, and is subsequently excited in a plasma to facilitate analysis by a conventional spectrometer.

Abstract: A method of collecting and processing geochemical samples in which particles which are contained on the very surface, or surficial layer of the earth, or of vegetation are collected, and are graded to exclude fine particles below about 50 microns in size.

Abstract: A pulse generator for energizing a coil with periodic bipolar current pulses of predetermined aplitude, period and repetition rate and of generally square wave form. The coil to be energized is connected in parallel with a capacitor to form a closed under damped tuned circuit of predetermined frequency. Current flowing through the coil is suddenly interrupted, causing a sinusoidal voltage to be generated across the tuned circuit. The current flowing through the coil rapidly changes according to a cosine function. At a time when the current has reached its maximum positive or negative value or slightly before, controlled rectifiers in the circuit between the power source and the tuned circuit are caused to conduct thus maintaining the current in the coil at a level substantially equal to the maximum value. At the end of a predetermined interval, the supply of direct current to the tuned circuit again abruptly is interrupted, thus defining another edge of a pulse.

Abstract: A method and apparatus for geochemical exploration for mineral, hydrocarbon and geothermal deposits in which particles which are contained in the very surface, or surficial layer of the earth, or of vegetation, or water are collected and analyzed.

Abstract: A spectrometer having two photoelectric channels the outputs of which are compared in order to measure gas or liquid concentrations, and means for automatically balancing the photoelectric channels immediately prior to each successive measurement, said means including a reference source of radiation which is utilized for balancing both photoelectric channels, so that when a measurement of the gas or liquid is being made, both photoelectric channels as nearly as possible are effectively balanced.

Abstract: Particles in a first fluid are transferred to a second fluid by confronting a stream of the first fluid with a stream of the second fluid in an enclosed region so that the particles will travel from the first fluid across said region to the second fluid by virtue of their momentum. The respective pressures of the first and second fluids is such that there is no appreciable mixing of the stream of the second fluid carrying particles with the first fluid.

Abstract: Exploration method and apparatus in which atmospheric particulates are collected, and wherein micro-organisms present in the collected particulates are analyzed for pre-determined elements or compounds.

Abstract: Method and apparatus for airborne prospecting in which samples of atmospheric gases, vapors or particulates are collected and contemporaneously the atmosphere near where the samples are collected is monitored to determine whether the respective samples were uplifted by an updraft of air. Samples respectively collected during periods of updrafts are separated from the remainder of said samples, and the samples respectively collected during periods of updrafts are analyzed separately from the remainder of said samples.

Abstract: A method of determining the presence of hydrocarbon seeps in the sea from an aircraft or other moving vehicle wherein an intense beam of light from an artificial source such as a laser is directed towards the sea and reflections and/or bioluminescence attributable to said beam occurring in the near surface of the sea are observed in the vehicle. Means is provided for discriminating between responses attributable to reflections from the surface of the sea and reflections and/or bioluminescence occurring below the surface of the sea.

Abstract: A method of detecting conductive bodies in an area wherein a primary field having a complex waveform, such as a frequency modulated, rapidly swept signal is generated and is radiated toward the area. A receiving system is provided for sensing the primary and secondary fields. Computerized signal processing techniques are used to obtain the best match between the waveforms of the received signals and those of stored reference waveforms which correspond to responses of known conductive bodies.