Abstract: The present invention provides a pump device 50 which is usable to dilute a sample 52 before analysis. A first pump 54 pumps the sample to a mixing region 58 where it mixes with a diluent 66. A second pump 64 pumps the diluted sample to the analysis instrument. The flow of the diluent to the mixer is equal to the difference of the flow of the sample to the mixer and the flow of the diluted sample to the instrument. Pumps 54 and 64 are independently controllable by a controller unit which is arranged so that data from the instrument can be used to determine the dilution factor of the sample. Thus, the controller can control this dilution factor in real time, upon receipt of such data from the instrument, by change either one of (or both) the pump's flow rate.

Abstract: A parallel-plate diffusion gas dehumidifier has a treatment zone having at least one water-permeable membrane. The gas dehumidifier includes an untreated gas inlet, a treatment zone bounded by water-permeable membranes, a support structure for the membranes, access to a source of vacuum, and a dehumidified gas outlet. The cross section of the treatment zone may be provided in various shapes, for example, rectangular. The gas dehumidifier inlet and outlet include flow transitions that minimize the obstruction of particles passing through the dehumidifier. The dehumidifier may be used in particle sampling systems to dehumidify the sample gas prior to introducing the sample gas to a mass measuring device and mass flow controller. Methods of operating the gas dehumidifier and the particle sampling system are also provided.

Abstract: A parallel-plate diffusion gas dehumidifier has a treatment zone having at least one water-permeable membrane. The gas dehumidifier includes an untreated gas inlet, a treatment zone bounded by water-permeable membranes, a support structure for the membranes, access to a source of vacuum, and a dehumidified gas outlet. The cross section of the treatment zone may be provided in various shapes, for example, rectangular. The gas dehumidifier inlet and outlet include flow transitions that minimize the obstruction of particles passing through the dehumidifier. The dehumidifier may be used in particle sampling systems to dehumidify the sample gas prior to introducing the sample gas to a mass measuring device and mass flow controller. Methods of operating the gas dehumidifier and the particle sampling system are also provided.

Abstract: A particulate mass monitor includes a controller that monitors a change in a resonant oscillation frequency of a taut metallic membrane, as caused by deposition of the particulate matter on the metallic membrane. The metallic membrane, such as a foil or metallized plastic film, is substantially mechanically stable under tension. Application of a tension to the periphery of the metallic membrane generates a substantially constant tension within the membrane, thereby allowing the particulate mass monitor to detect a particulate mass concentration of the air sample with a relatively high degree of accuracy. Additionally, the particulate mass monitor includes a membrane transporter that automatically advances the metallic membrane within the particulate mass monitor. The membrane transporter minimizes the necessity for manual replacement of the metallic membrane over time and allowing long term, unattended operation of the particulate mass monitor.

Abstract: A test circuit employs use of first and second switches to operably charge a capacitor to over 500 volts and, thereafter, discharge energy stored in the capacitor to test an over-voltage protection circuit associated with a pin of a semiconductor device. When switched by a controller, the first switch couples a high voltage source to charge a capacitor. After completing this charge phase, the controller opens the first switch, decoupling the high voltage source from the capacitor. The controller then activates the second switch to couple the capacitor to the pin of the semiconductor device. During this discharge phase, energy in the capacitor discharges through the protection circuit of the semiconductor device. Use of a high-voltage dry reed vacuum relay as the first switch provides better isolation of the high voltage source from the capacitor, avoiding a presence of an unwanted residual voltage component in a simulated ESD test pulse.

Abstract: A clip is used with a pilaster assembly, where the clip is snap-fit into the slots of the pilaster, so that the clip is retained when inserted into the slots. This provides the advantage that the clips tend not to fall out due to bumps or vibrations such as those that can occur, for example, during transport of a cabinet having the pilasters and clips.

Abstract: A flood gun 10 for charge neutralization of an analysis region Ra of a sample S downstream of the flood gun, comprising: a first source 30 of electrons; a second source 50 of positively charged particles; and an extraction and focusing assembly 60,64, arranged to: (i) extract a first, electron beam from the first source and focus the first beam to a first flood area Ae at the analysis region; and (ii) extract a second, positive particle beam from the second source and focus the second beam to a second flood area Ai at the analysis region. The electron beam and the positive particle beam may both be extracted and focused simultaneously, in a single mode of operation or, alternately, in a dual mode of operation. A corresponding method of providing charge neutralization and a spectroscopic system for secondary particle emission analysis are disclosed.

Abstract: The present invention provides a pump device 50 which is usable to dilute a sample 52 before analysis. A first pump 54 pumps the sample to a mixing region 58 where it mixes with a diluent 66. A second pump 64 pumps the diluted sample to the analysis instrument. The flow of the diluent to the mixer is equal to the difference of the flow of the sample to the mixer and the flow of the diluted sample to the instrument. Pumps 54 and 64 are independently controllable by a controller unit which is arranged so that data from the instrument can be used to determine the dilution factor of the sample. Thus, the controller can control this dilution factor in real time, upon receipt of such data from the instrument, by change either one of (or both) the pump's flow rate.

Abstract: A metal detector has a circular excitation coil (10) through which foodstuffs to be tested (65) pass, on a conveyor belt (40). The excitation coil (10) is excited by a stable oscillator (50) and the lines of flux generated by the excitation coil (10) link two receiver coils (20, 30) equidistantly spaced either side of the excitation coil (10). As a foodstuff (65) having a foreign ferromagnetic or electrically conductive object therein passes through the receiver coils (20, 30), a voltage is induced in them. This induced voltage is phase compensated. The change in amplitude or frequency of the oscillator (50) as the foodstuff (65) moves through the excitation coil (10) is also passed to the processor (70) which removes the artifacts from the detector signal caused by the volume of the foodstuff (65) itself. The resultant signal, which was previously swamped by the effect of the volume of the foodstuff itself, can then be detected and the foodstuff can be removed from the conveyor (40).

Abstract: A multi-way radiation monitoring and detection system is capable of detecting a radiation source on or within traffic that can travel within M adjacent traffic ways, where M is an integer equal to or greater than a value of 2. The radiation detection system comprises a set of (M+1) radiation detector assemblies with individual radiation detector assemblies of the set of (M+1) radiation detector assemblies respectively positioned at each of two sides of each of the M adjacent traffic ways. A set of M controllers is included and each controller is associated with a respective traffic way of the M adjacent traffic ways. Each controller is coupled to the respective individual radiation detector assemblies positioned at the two sides of the traffic way to which that controller is associated, such that two controllers associated with two adjacent traffic ways couple to the individual radiation detector assembly positioned between those two adjacent traffic ways.

Abstract: A flood gun 10 for charge neutralization of an analysis region Ra of a sample S downstream of the flood gun, comprising: a first source 30 of electrons; a second source 50 of positively charged particles; and an extraction and focusing assembly 60,64, arranged to: (i) extract a first, electron beam from the first source and focus the first beam to a first flood area Ae at the analysis region; and (ii) extract a second, positive particle beam from the second source and focus the second beam to a second flood area Ai at the analysis region. The electron beam and the positive particle beam may both be extracted and focused simultaneously, in a single mode of operation or, alternately, in a dual mode of operation. A corresponding method of providing charge neutralization and a spectroscopic system for secondary particle emission analysis are disclosed.

Abstract: An ion source for use in a mass spectrometer includes an electron emitter assembly configured to emit electron beams, wherein the electron emitter assembly comprises carbon nanotube bundles fixed to a substrate for emitting the electron beams, a first control grid configured to control emission of the electron beams, and a second control grid configured to control energies of the electron beams; an ionization chamber having an electron-beam inlet to allow the electron beams to enter the ionization chamber, a sample inlet for sample introduction, and an ion-beam outlet to provide an exit for ionized sample molecules; an electron lens disposed between the electron emitter assembly and the ionization chamber to focus the electron beams; and at least one electrode disposed proximate the ion-beam outlet to focus the ionized sample molecules exiting the ionization chamber.

Abstract: A fluid flow transducer module includes a fluid flow conduit having an inlet for receiving fluid, a transducer for measuring rate of flow of the fluid, an interface in communication with the transducer and adapted to receive rate of flow measurements from the transducer, the conduit having an outlet for flowing the fluid from the transducer to a reservoir, the outlet extending transversely of the conduit, a housing for the conduit, conduit inlet, conduit outlet, and transducer, the housing having opposed first and second walls, each wall having an opening for the outlet therein, and at least one of the walls being adapted for stacking engagement with a second transducer module of a same structure, such that the outlets of the modules are aligned to form a common conduit, and the interconnected modules form a flow transducer assembly having a plurality of fluid flow conduits and transducers.

Abstract: A spectroscopic analyser and method of use, for surface analysis spectroscopy, are disclosed. The spectroscopic analyser 10 has a time-of-flight (TOF) spectrometer which analyses secondary electrons emitted from a surface of a sample 30 on excitation by an irradiation source 40. The TOF spectrometer includes a gate 50, which receives and selectively passes a proportion of the secondary electrons by pulsed deflection or retardation of the electron beam using gating members 55. In that manner one or more pulses of electrons enter a magnetic field-free flight tube 90 and reach a detector 120 downstream of the gate 50. The flight times, and therefore energies, of the detected electrons through the flight tube 90 are thereby detected. A curved electron mirror 100 may be used to increase the flight path of the pulsed electrons in the flight tube 90, thereby increasing the spread of each electron pulse within the analyser 10.

Abstract: A fluid flow transducer module includes a fluid flow conduit having an inlet for receiving fluid, a transducer for measuring rate of flow of the fluid, an interface in communication with the transducer and adapted to receive rate of flow measurements from the transducer, the conduit having an outlet for flowing the fluid from the transducer to a reservoir, the outlet extending transversely of the conduit, a housing for the conduit, conduit inlet, conduit outlet, and transducer, the housing having opposed first and second walls, each wall having an opening for the outlet therein, and at least one of the walls being adapted for stacking engagement with a second transducer module of a same structure, such that the outlets of the modules are aligned to form a common conduit, and the interconnected modules form a flow transducer assembly having a plurality of fluid flow conduits and transducers.

Abstract: In a method for determining the flow rate of a fluid flowing in a channel (2), the fluid being constituted by a liquid or a gas, two pulse shaped, oscillating signals are sent through the medium with one signal directed against (14) and the other signal directed with (12) the flow direction (4) of the fluid. The transmitted signals are received and the flow rate is determined by means of the phase shift between the received, pulse shaped signals caused by the flow of the fluid. The phase shift (20) between the signals is determined while compensating for the dwell time of the pulse shaped oscillating signals in the fluid.

Abstract: An optical measurement assembly includes a processor for providing a light source, for receiving light from a sample, and for analyzing the received light for detecting and measuring a target substance, and an optical head including a housing, a source light mirror mounted in the housing for directing a light beam onto the sample, the beam having a central axis extending from the source light mirror, a collector mirror mounted in the housing and having a central axis coinciding with the light beam central axis, and configured to receive light reflected from the sample, and a return mirror disposed in the housing for receiving light from the collector mirror. A source light guide extends from the processor light source to adjacent the optical head source light mirror, and a return light guide extends from adjacent the optical head return mirror to the light receiving means in the processor.

Abstract: A method for forming composite articles, particularly ceramic articles, from particles or fibers mixed in a thermally activated reactant gas stream. The particles or fibers are codeposited with material produced by chemical vapor deposition (CVD) onto a heated substrate until the desired thickness of composite is obtained. Removal of the substrate yields a near-net shaped codeposited composite article having a chemical vapor deposition produced matrix with particles or fibers embedded therein in a generally uniform distribution. The method provides high deposition rates, and the composite articles produced may have enhanced strength, thermal shock resistance, and corrosion resistance at elevated temperatures.

Abstract: Disclosed is a method for forming composite articles, particularly ceramic articles, from particles or fibers mixed in a thermally activated reactant gas stream. The particles or fibers are codeposited with material produced by chemical vapor deposition (CVD) onto a heated substrate until the desired thickness of composite is obtained. Removal of the substrate yields a near-net shaped codeposited composite article having a chemical vapor deposition produced matrix with particles or fibers embedded therein a generally uniform distribution. The method provides high deposition rates, and the composite articles produced may have enhanced strength, thermal shock resistance, and corrosion resistance at elevated temperatures.

Abstract: A new method and apparatus for providing a stable, temporally controllable high current density electron beam from a photocathode has been developed. A low level of cesium and, possibly a stabilizing gas, is supplied to the photoemitting surface while the electron beam is being generated, thereby replenishing cesium and possibly other ions lost from the emitting surface on a continual basis.