Abstract: These thick elements are all corrected for third order spherical aberration and they are also corrected for spherochromatism (i.e. chromatic variation of spherical aberration) or longitudinal color or both. Most are preferably made of materials of low index of refraction less than 1.55, such as BK-7 or fused silica.Most elements corrected for third order spherical and spherochromatism exhibit longitudinal color, but this poses no problem when they are used with a single wavelength laser. Such systems can be used to focus a laser beam to provide a very fast f number diffraction-limited point source, or used in optical testing, experiments, and the like. The designs are characterized by an extremely low sensitivity of performance to wavelength changes and thus to uniform temperature changes (thermal soaks). A temperature change of several hundred degrees centigrade--from cryogenic temperatures up to near the melting point of the optics, has essentially no effect on the predicted performance.

Abstract: A method for manufacturing X-ray lithography masks containing features smaller than 1 micron in size and having conductive or non-conductive substrates. The method involves the initial deposition, as by evaporation, of a very thin coating of a strong X-ray absorber such as gold. A layer of photoresist is applied to the initial gold layer and exposed and developed to remove the photoresist in the exposed areas. Thereafter, the mask is submerged in an electroless gold plating bath. I have discovered that metals suitable for electroless plating are autocatalytic in nature. Accordingly, additional gold from the bath is preferentially deposited on the exposed first gold layer and is permitted to build to the desired thickness.

Abstract: A rotatable drum switches a vacuum source on and off towards an outermost bill in a stack to separate bills one at a time at high speeds from the stack and provide registration between the separate bills. As the bills are separated from the stack, means are provided to maintain a relatively constant pressure on the stack of bills. Flexible bands transport the separated bills away from the stack.

Abstract: There is disclosed a secondary ion mass spectrometer to be used with other spectro analysis mechanisms where the sample holder is fixed in a main vacuum chamber having a secondary vacuum chamber communicating with the main chamber with a vacuum seal between the two in which a substantially 90.degree. spherical segment energy analyzer is disposed in the second vacuum chamber along with a quadrupole mass spectrometer and electron multiplier. A primary ion gun is disposed within the main vacuum chamber directing an ion beam at the samples to be tested and the secondary ions emitted are collected through a longitudinal extraction lens mechanism disposed between the 90.degree.

Abstract: A method and circuitry for maintaining the precise temperature of atomic absorption spectroscopy graphite specimen tubes over wide temperature ranges independently of the tube emission factor. The infrared radiation of a heated tube is measured by a detector, the signal from which is amplified in a variable gain amplifier, then compared with an externally generated "temperature select" signal, and the error signal therefrom controls a circuit that in turn controls the heating power to the graphite tube. A second measurement of the heated tube is made by a detector sensitive only to short wavelength radiation, e.g., visible, which is substantially unaffected by emission factors, and the signal therefrom adjusts the gain of the variable gain amplifier to thereby correct the infrared generated signal for variation in tube emission factors.

Abstract: A current sharing modular power system including, in each module, an inverter circuit and means to determine the current to a common load from the module. A difference circuit is provided to determine the difference between the module supplied current and the average of the current supplied by the other modules. The difference is then utilized to vary the pulse width of the inverter output so that the pulses are wider if the current from the module is smaller than the current supplied by the other modules and the pulses are thinner if the current from the module is larger than the average current supplied by the other modules. The system also includes a voltage sense circuit to adjust the module operation to maintain a constant voltage output.

Abstract: Method and apparatus for generating a gaseous test sample from a liquid sample and for transferring this test sample into a measuring cuvette of an atomic absorption spectrometer, in which an inert gas flow is directed through a sample vessel and into a measuring cuvette and, after the air has been displaced from the sample vessel, a reagent is added for generating a gaseous test sample, the test sample being carried into the measuring cuvette by the inert gas flow, wherein prior to the adding of the reagent, the flow rate of the inert gas flow is changed-over from a higher value to a lower value.

Abstract: Apparatus for determining the concentration of the various components of a sample, which includes a spectrophotometer for receiving a sample to be analyzed and performing extinctions of the sample at a plurality of preselected wavelengths to form a sample spectrum; memory devices for storing a standard spectra of each of the individual components; circuitry for weighting the sample spectrum at different wavelengths in conformity with each of the standard spectra and providing estimated values of the concentrations of the components from the sample spectra thus weighted; circuitry for reconstructing the sample spectrum as a linear combination of the estimated values of the concentrations and the standard spectra; a subtractor for forming a difference spectrum from the sample spectrum and the reconstructed sample spectrum; circuitry for weighting the difference spectrum at different wavelengths in conformity with each of the standard spectra and providing corrective values of the concentrations of the component

Abstract: Method and apparatus for chemical treatment of workpieces is disclosed wherein a workpiece to be processed is exposed to a controlled gaseous atmosphere containing a gaseous constituent to be dissociated by laser radiation to produce a gaseous reactant product for reaction with a surface of the workpiece for chemical processing of the workpiece. The wavelength of the laser beam radiation is selected for splitting only the desired bonds to produce only the desired reactant product without producing undesired by-products which could deleteriously interfere with the desired chemical reaction.

Abstract: An apparatus for detecting quality of currency or the like. Signals representative of the transmissivity and reflectivity of a bill are subtracted from a signal representative of unity. The resulting signal, which is representative of absorptivity of light by the bill, is accumulated over the length of the bill and compared to a reference to produce digital signals representative of fit or unfit bills.

Abstract: A document processor for transporting documents through a path, detecting flaws thereon by electronically scanning each side of the document, printing selectable indicia only on unflawed documents, and sorting and storing separately the flawed and unflawed documents. The electronically scanned information is compared with a master document stored in a computer memory. As a result of this comparison, outputs are provided from the computer which are indicative of a favorable or unfavorable comparison for controlling the printing and sorting functions.

Abstract: An oxidant flow conduit having a restriction and branching downstream of the restriction to provide a primary flow conduit for supplying oxidant to a nebulizer and an auxiliary flow conduit having an adjustable valve for supplying oxidant to a mixing chamber is provided. A differential pressure transducer measures the pressure drop across the restriction to provide an output signal. A primary fuel conduit is provided having a pair of restrictions with an adjustable valve for supplying fuel to the mixing chamber. A boost conduit having a restriction is connected to the primary fuel conduit and between the restrictions providing for supplementing the fuel to the mixing chamber when a different fuel mixture is used. A differential pressure transducer measures the pressure drop across the pair of restrictions to provide an output signal. A square root linearization operation is performed on each signal in a microprocessor and modified output signals drive respective fuel and oxidant digital displays.

Abstract: Closure for a sample vial utilized to introduce sample into a gas chromatograph in accordance with the head space method. The closure includes a flexible disc for closing the opening through the neck of the vial and overlying the margin of the neck about the vial opening. A cap having a central aperture defining an annular shoulder about the aperture overlies the disc. The cap has an annular depending skirt encompassing the disc for clamping about the neck of the vial to retain the disc and the cap on the vial. A portion of the closure is deformable for venting the vial to atmosphere in response to a pressure within the vial when the closure is applied thereto in excess of a predetermined pressure.

Abstract: There is disclosed a system for storing a projection mask of the type used for printing integrated circuit patterns on silicon wafers. A special cassette package permits the mask to be stored in a clean sealed environment. A delivery system transports the sealed cassette into an optical projection instrument wherein the cassette is opened and the mask advanced to the projection stage. After projection, the mask is returned and automatically sealed into the cassette. The cassette may be evacuated or, alternatively, filled with a clean gas. The mask sealed in the cassette can then be stored until its use is again required.

Abstract: The invention relates to a spectrometer including a rotatable dispersive element, a stepping motor for varying the angular position of said dispersive element, a program transmitter for controlling said stepping motor, a timing generator and a recording instrument.

Abstract: Polymer membranes are formed by spinning a monomer solution on a smooth surface of a plate and heat curing the solution to form a polymer film. A carrier element is attached to the film and together they are immersed in a suitable chemical composition to react with the bond between the film and plate. The assembly is then immersed in water to cause the plate to fall away from the film.

Abstract: An apparatus for automatically scaling an X-Y recorder for use with a thermal analyser wherein temperature range span during an experiment may be plotted exactly scaled to an abscissa such that the left side of the graphical representation corresponds exactly to the minimum temperature during the experiment and the right side of the representation corresponds exactly to the maximum temperature achieved.

Abstract: A system for use in thermal analysis for correcting discrepancies between oven temperature and desired sample temperature including means for automatically calibrating the system at several selected points in the analytical temperature scale wherein actual sample temperature is forced to agree exactly with desired sample temperature by appropriately changing oven temperature and wherein the calibrated sample temperature and the difference between oven temperature and sample temperature at the several points are used to correct for discrepancies throughout the intervening analytical temperature scale.

Abstract: An improved melting point temperature standard includes a well for receiving a temperature sensor to be calibrated. Surrounding the well is a cell with a crystalline material therein. A thermally conductive spacer contacts the outer cell walls. A thermal barrier contacts the spacer and a second thermally conductive member encircles the barrier. A heating/cooling element contacts the second thermally conductive member to apply heat or to cool it. Thermistors in the second thermally conducive member and the spacer are used by a control circuit to adjust the heat flow into the cell so that the crystalline material melts over a period of 7 to 8 hours making use of the temperature standard possible for many hours.

Abstract: An optical system providing a new field lens corrector group for a two mirror telescope. The field group corrector has a negative net power and allows the resulting system to have a long back focus and low obscuration while covering a wide field of view. The field corrector group provides the overall system with good Petzval curvature aberration correction characteristics because the aberration of the corrector group is of opposite sign to the Petzval curvature aberration of the two mirror system. The negative field corrector group is designed to increase the f number speed of the two mirror system.