Abstract: An apparatus useful for flameless atomic absorption spectroscopy includes a sample carrier adapted for receiving non-gaseous sample material and means for radiantly heating the sample carrier to effect the uniform thermal decomposition thereof.

Abstract: The vitiating effect on the fluorescence measuring signal of extraneous currents flowing through the fluorescence detection means in flash spectrofluorimetry is almost completely eliminated by integrating the output of the fluorescence measuring means for the duration of the signal period, which includes a flash duration, and again for an equal period occurring between flashes which therefore does not include a flash duration. The second integral is then subtracted from the first to obtain a fluorescence measuring signal substantially unaffected by extraneous currents, such as dark current, sample phosphorescence, etc. The invention is applicable to single- and double-channel operation. In the latter, in addition to the fluorescence measuring channel there is provided a fluorescence reference channel. This enables the fluorescence measuring signal and the fluorescence reference signal to be ratioed together, the effect of extraneous currents having first been eliminated in both.

Abstract: The combination of an electrically conductive hollow body, a step-down transformer operable at a frequency greatly in excess of 1 kHz and solid phase temperature depressing means is used to realize the invention in its method and apparatus aspects. The temperature depressing means serve to bring the hollow body to a given depressed temperature so that when a gas component entrained in a gas carrier with which it forms mixture is passed through the hollow body for a period of, say, a few minutes the gas component condenses in the hollow body. The condensed component may later be freed and re-injected into the carrier by a process of thermal desorption which is achieved by direct ohmic heating of the hollow body via of the step-down transformer. The desorption time would typically extend over some ten seconds or so, as against the condensation time of several minutes, with the result that the gas component is concentrated in time, i.e.

Abstract: A direct current servo motor operates through a toothed belt linkage to drive the pen carriage of a chart recorder. The position of the drive is monitored by a sectored encoder disc on the motor shaft. A pair of optical sensors is located relative to the encoder disc to provide alternately phased transition signals as corresponding edges of the encoder disc sectors pass the sensors when the motor rotates. A microprocessor interrupted by a transition signal goes to a sub-routine that determines which way the encoder disc is rotating and stores a count signal of the corresponding sign in a register. Further the microprocessor compares an input signal with the stored count signal and directs the motor to rotate in the direction that will reduce the difference or error signal to zero thus causing the pen to follow the magnitude of the input signal.

Abstract: An effusion cell assembly is disclosed and includes a temperature sensor designed to balance sensor temperature and cell crucible temperature by an increased heat radiation collection.

Abstract: An improvement to a chart recorder where the chart paper is driven by a motor responsive to pulses counted by a microprocessor makes it possible for the operator to return the pen at any time to the starting point of the last chart scan by merely pressing a key. Using a programmed counter the microprocessor keeps track constantly of the number of counts since the start of the scan. On key command the microprocessor directs the motor to return through this number of counts plus 50; then to go forward 50 counts thus taking up any backlash in the chart drive so as to return exactly to the initial point of the scan. The subroutine also raises the pen during return and lowers it at the starting point.

Abstract: An improvement to a chart recorder where the chart paper is driven by a motor responsive to pulses counted by a microprocessor makes it possible for the operator to set the pen to a major grid line on the chart at any time after initialization by merely pressing a key. Using a programmed counter the microprocessor keeps track constantly of how many counts the paper has advanced and how far it is to the next major grid line. Upon key command the microprocessor through a software routine advances the paper to the next major grid line. If desired, the routine can also be programmed to raise the pen during advance and lower it at the major grid line.

Abstract: An apparatus useful for positioning a light filter includes an incrementally stepped motor having the light filter affixed thereto. The apparatus also includes means for detecting a light signal and incrementing the motor in response thereto.

Abstract: A mechanism for providing for the one-handed control of a rotary feedthru includes bi-directional braking means which is controllable by the same element used for imparting rotation to the feedthru.

Abstract: A discharge lamp firing apparatus is disclosed which includes providing only the necessary firing voltage to the lamp prior to the firing thereof. As such, the surrounding system is not subjected to transients caused by conventional mechanisms which suddenly switch an extremely high voltage across the lamp. As a result, the present apparatus protects the associated circuitry as well as prevents needless overvoltage conditions to the lamp.

Abstract: An apparatus for enriching a sought element from a solution for flameless atomic absorption spectroscopy includes a constant voltage current source. The solution is enriched by electrodepositing the sought element therefrom and integrating the current with respect to time.

Abstract: This invention relates to a spectrophotometer which includes a burner adapted for burning a gaseous fuel and for atomizing a sample to be analyzed in a burner compartment, mechanical elements or electrical circuitry serving to periodically pass a beam of light through the burner compartment, a detector, electrical circuitry for energizing the detector during the period of absence of the beam of light through the burner compartment, said detector being adapted when energized to produce an electronic signal representative of the presence of a flame in the burner compartment; and control elements responsive to the electronic signal for controlling the feeding of fuel to the burner.

Abstract: A mechanism for automatically supplying sample fluids to a chromatographic column is provided. The mechanism obviates the need for sealed sample containers as well as the need for pressurized gas commonly employed to force sample fluid from the sealed containers.

Abstract: A sample transport system adaptable for use in an MBE instrument includes means for introducing a plurality of substrates into a storage chamber and means for conveying each substrate on a preselected basis to a processing chamber whereby the wafers not being processed are completely protected against contaminants which may occur within the processing chamber.

Abstract: A sample transport vessel including a sample block carrier is capable of forming a hermetic seal with a sleeve portion of a lid member. When assembled, the vessel can be used to transport chemically active materials without contamination thereof. In addition, an analytical instrument includes elements adapted to cooperatively interface with the transport vessel.

Abstract: An apparatus useful in the flameless atomic absorption spectroscopy analysis of a sample includes an electrically conductive sample carrier adapted to be heated whereby drying and ashing steps can be performed by passing an electric current therethrough. By use of such an apparatus, the temperature at which the ashing process occurs can be controlled.

Abstract: A chamber useful with an atomic absorption spectrometer includes at least two atomization means installed therein. The means can be serially aligned with the measuring beam or arranged parallel to the axis thereof.

Abstract: A method for concentrating a vapor of a mercury sample solution is carried out by an apparatus having an electrode of amalgam-forming material which electrode is movable from the sample solution to a heated portion within a tube.

Abstract: An apparatus and method useful for analyzing refractory substances includes a means for locally heating a sample portion of a refractory material to generate the dissociated vapor thereof.

Abstract: An improved photodetector arrangement comprises positioning a photodetector having at least one semitransparent cathode so that the light beam striking the cathode passes through it at least twice before exiting from the photodetector. In another embodiment of the invention, a second photodetector is positioned relative to a first photodetector so that the light beam, after striking the first photodetector, strikes the second photodetector. Where the two photodetectors are employed, they may be electrically connected in parallel.