Abstract: Atomic absorption spectrometer sample supply apparatus for producing a gaseous sample for analysis and for transferring the sample to the atomic measuring cuvette. The sample supply is in a sealed vessel and, by directing the flow of a pressurized inert gas, the sealed sample vessel is first purged of contaminating air, a volatilizing reagent is forced by inert gas pressure into the sample, and a small specimen of the gaseous sample is transferred by gas pressure into the cuvette inlet tube.

Abstract: Method and apparatus for preparing a liquid sample for combustion and analysis in an elemental analyzer. In order to avoid damage to the quartz combustion tube and ladle by molten aluminum, the sample is placed in an aluminum foil vial which is crimped and placed in turn in an open ended capsule of nickel or other non-reactive metal. The capsule is then distorted by a novel encapsulator to partially obstruct the open end and retain the liquid sample vial therein during the combustion process.

Abstract: An improved method and apparatus for attaching a target to the cathode of a cathode sputtering system is disclosed which includes a ferromagnetic retainer which releasably clamps the target to the cathode by virtue of its attraction to existing permanent magnets in the cathode assembly. An optional ferromagnetic ring may also be provided around the periphery of the target to further hold the target to the cathode assembly.

Abstract: Inaccuracies resulting from measuring the internal temperature of absorption spectrophotometer graphite tube furnaces by pyrometric measurements of a spot on the external surface of the graphite tube are overcome by a novel arrangement in which the pyrometer detector measures the interior through the tube end and at an angle that permits a view of the entire interior length without interfering with the spectrophotometer sample beam.

Abstract: An adjustable pitch, zero backlash, rotary-to-linear-motion converter particularly adaptable for the precision positioning of linearly movable light weight mechanisms. The spherical bearing ends of three or more dumbbell-shaped rollers, in an interference fit between a rotatable shaft and the inner surface of a cylindrical sleeve, are partially enclosed in end cages which are clamped together but which may be adjusted so that the parallel roller axes are offset from the shaft axis whereby rotation of the shaft will provide rectilinear movement to the sleeve.

Abstract: Disclosed is a sample feeding apparatus having a housing defining first and second chambers sealed one from the other and a needle movable longitudinally with respect to the housing. The first and second chambers continuously receive carrier and purging gases respectively through suitable conduits. The needle has an opening normally in communication with the second chamber for continuously purging the needle. Upon application of a sample vessel to a member telescopically received about the housing, the needle is displaced through a seal into the first chamber. Carrier gas is thus provided through the needle into the head space of a sample vessel and the sample will flow to the injection block of a gas chromatograph in response to pressure compensation between the injection block and head space. Upon withdrawal of the sample vessel from below the sampling apparatus, the needle is spring returned to its initial position preventing carrier gas from flowing from the first chamber through the needle.

Abstract: A method and circuitry for the pyrometric measurements of temperatures of graphite tube atomizers for flameless atomic absorption spectroscopy over very wide temperature ranges of, for example, 100.degree. C.-2700.degree. C. independently of the emission factors of the various graphite tubes. The heated tube is measured by a radiation pyrometer which has a very wide temperature measuring range but with an accuracy that is affected by tube emission factors and is also measured by an independent measuring system which is accurate independently of the emission factor at some particular elevated temperature. When the graphite tube reaches that elevated temperature, the output signals of both systems are mixed to produce an error signal that is used to accurately calibrate the pyrometer circuitry. Since it has been found that the percentage variation of emission factor is independent of graphite tube temperatures, the pyrometer will now produce accurate measurements over a very wide temperature range.

Abstract: A valve having a plunger with opposite end sections of equal diameter, a control section of lesser diameter and a valve member. One end section extends from the inlet chamber through a seal to the exterior of the valve, and the other end section extends from the outlet chamber through a seal to the exterior of the valve. The inlet and outlet chambers are connected by a central bore having a diameter equal to that of the plunger end sections. The central section of the plunger extends through the central bore. The valve member seats against one end of the central bore to close the valve. Because of the equal diameters of the axial bores of the end sections and the central bore, the force exerted on the plunger by fluid pressure in the valve are balanced regardless of the plunger position, i.e., open, closed, or at any intermediate position.

Abstract: At least two posts are extended from a deformable specimen and individual force couples are applied through each post to vary the configuration of the specimen. Specific embodiments are disclosed wherein the specimen is a flexible mirror in an optical system; in one form thereof, parallelogram linkages apply the force couples to the posts, and in another form thereof, extension assemblies are mounted between the posts which are each actuated by a remotely disposed actuator through a flexible drive.

Abstract: A spectrophotometer detector cell assembly having improved sensitivity, has a cell defined by a bore through a body and closed at the ends by radiation transparent windows with inlet and outlet passages through the body to the bore, so that radiation passed through the sample fluid flowing through the bore is detected by a photodetector. The body, which is made of a thermally conductive material, is a large thermal mass is relation to the volume of the cell and a tubular inlet conduit, also made of a thermally conductive material, wraps around the body and connects to the inlet passage so that fluid flowing into the bore will tend to reach a stable temperature due to the heat sink effect of the body and conduit thereby stabilizing the refractive index of the fluid in the bore and enhancing the sensitivity of the photodetection.

Abstract: A flame spray powder comprising particles having a core of nickel, iron, copper, cobalt or alloys thereof coated with a binder containing discrete particles of aluminum and substantially pure nickel. The core material should be present in amounts of 70-98, and preferably 80-94, weight percent of the total metal content of the powder. The core particles should range in size between -60 mesh and +3 microns, and preferably -100 mesh and +400 mesh. The core material is most preferably nickel, and the coating may, in addition to the aluminum and nickel, contain molybdenum.

Abstract: A laser optical system which includes a mirror system for forming a mirror cavity, a laser target disposed in this cavity, a plurality of focused laser beams directed into the cavity, and the mirror system being so arranged that each of the laser beams is reflected off the walls of the cavity a plurality of times prior to being focused on the laser target to thereby heat the target to a very high temperature.

Abstract: A graphite tube atomizer for flameless atomic absorption spectroscopy includes a graphite tube disposed to permit passage of a measuring beam therethrough. The graphite tube is engaged at opposite ends by annular contact pieces which are coupled to a source of electrical current. The contact pieces are supported in housing portions which serve to surround the graphite tube and provide a chamber into which cooling gasses can be admitted. The cooling gasses also serve to reduce deterioration of the graphite tube. The housing portions are selectively movable either toward or away from each under the power of a drive mechanism. The housings may be urged by the drive mechanism toward each other so the contacts mounted thereon are in selectable pressure engaging contact opposite ends of the graphite tube.

Abstract: An improved optical chopper, developed particularly for use in a double beam atomic absorption spectrophotometer, receives light beams from two separate sources and sequentially switches them into two separate paths and instantly thereafter the second light beam enters the first path, followed immediately by the first beam entering the second output path and then the second beam entering the second path; alternatively, the chopper is arranged so that the first light beam enters the first output path followed by the first light beam entering the second output path, and then the second light beam enters the first path and the second light enters the second path; also, during one segment of the choppers cycle, both beams are blocked from both output paths.

Abstract: Power is applied to an electrical element in maintaining a thermal system at stabilized conditions and a feedback signal is derived to control the electrical input to the heating element by linearly combining functions of the current through the heating element and the voltage drop thereacross respectively. In one embodiment, each of the linearly combined functions in the feedback signal can be varied independently to change the stabilized conditions of the thermal system, while in another embodiment a microprocessor is incorporated to provide such variation for a sequential range of stabilized conditions.

Abstract: In a double beam, optical-null type infra red spectrophotometer, an optical system including a movable dispersive optical element causes transmission of a spectrum of light in respective beams through an adjustable optical attenuator and through a sample and thence to a sensing circuit. The sensing circuit provides an error voltage having an amplitude proportional to the difference between the intensites of the beams passing through the sample and through the attenuator respectively. The position of the attenuator is adjusted in proportion to the integral of the error voltage to cause a reduction thereof while, in response to the magnitude of the error voltage in excess of a threshold value, there is a reduction in the rate of movement of the dispersive element.

Abstract: Heat is applied to atomize the residual liquid from a sample transfer probe on which at least the tip is fabricated of heat resistant material. In one embodiment, the sample transfer probe is disposed within an atomic absorbtion spectrometer having a hollow graphite furnace that includes a port through which the sample is dispensed for atomization in the furnace. The probe tip in this embodiment is configured to extend into the graphite furnace while making thermal contact therewith so that the sample residue on the probe tip is atomized simultaneously with the sample in the furnace. Inert gas is connected to the sample transfer probe through a control valve to flush the atomized sample residue from within the probe tip in still another embodiment.

Abstract: Anticipation signals are derived for each peak whenever a differential exists within a closed loop having the electrical output connected to the input thereof and a confirmation signal is derived after each peak at a threshold level of the new slope polarity exceeding the noise level of the electrical output. The amplitude of each peak is stored as a voltage level which follows the electrical output throughout either slope polarity until a peak is reached and this voltage level is continuously compared with the electrical output to derive the slope polarity thresholds. Otherwise, a very particular embodiment is disclosed with which the stored voltage level only relates to either the most significant maximum or minimum peak of the electrical output and the disclosed embodiments are related to instruments which perform spectral analysis.

Abstract: A chromatographic column fitting for connecting the column to a connecting tube, which includes a union having an axial through-bore that includes at both ends thereof: a first portion, a second inwardly tapered portion, and a third cylindrical portion connecting the second portions of both ends; one end of the connecting tube being receivable in one end of the union and one end of the column tube being receivable in the other end of the union so that the end of the two tubes engage in butt-to-butt relationship; and ferrules wedged between the outside surfaces of the tubes and their adjacent second portions of the union, respectively; and in another form thereof the invention provides an outlet column fitting which includes a T-shaped union having an inlet at one end and an outlet at the other end and having an axial through-bore, which includes sequentially from the inlet to the outlet, a first inwardly tapered portion, a second cylindrical portion, a third manifold portion, the union having a side inlet ope

Abstract: A pulse generator for producing two output pulse trains A and B where the total number of pulses in both train A and B over a fixed time period remains a constant. The two pulse trains are derived from a master clock which gates a plurality of cascade connected synchronous decade rate multipliers. A selector is set either statically or dynamically to the value N where N is the number of pulses desired in one pulse train out of every M pulses produced by the master clock. A summing means is coupled to all the multipliers to produce a first intermediate pulse train with N pulses for every M clock pulses. A difference means is coupled to each multiplier and to the master clock to produce a pulse in a second intermediate pulse train every time a clock pulse occurs and a pulse in the first pulse train does not occur. A pulse counter is coupled to each intermediate pulse train output to produce two output pulse trains A and B each having a substantially constant pulse frequency.