Abstract: An apparatus is provided which includes a sample holder for holding a reaction chamber which includes an optical interface, a fiber optic cable for delivering an excitation beam to a sample housed within the reaction chamber and for receiving light emitted by the sample, and a lens co-axially disposed with the fiber optic cable and positioned outside the reaction chamber for focusing the excitation beam through the optical interface and within a volume of the sample and for collecting and transmitting to the fiber optic cable light emitted within the volume of the sample.

Abstract: A system is provided for carrying out real time fluorescence-based measurements of nucleic acid amplification products. In a preferred embodiment of the invention, an excitation beam is focused into a reaction mixture through a surface, the reaction mixture containing (i) a first fluorescent indicator capable of generating a first fluorescent signal whose intensity is proportional to the amount of an amplification product in the volume of the reaction mixture illuminated by the excitation beam and (ii) a second fluorescent indicator homogeneously distributed throughout the reaction mixture capable of generating a second fluorescent signal proportional to the volume of reaction mixture illuminated by the excitation beam. Preferably, the excitation beam is focused into the reaction mixture by a lens through a portion of a wall of a closed reaction chamber containing the reaction mixture.

Abstract: In a gas chromatograph system having a column with a stationary phase and a carrier gas moving through the column to contact the stationary phase, the system being useful for detecting analytes in a sample, a method and apparatus for predicting the retention times for the analytes under various conditions, the method utilizing the steps of:a) detecting the analytes under a number of sets of given conditions;b) calculating values for various parameters characteristic of the system based on a mathematical model that includes a correction to compensate for the permeability of said column to said carrier gas;c) entering into the model the values for the characteristic parameters and at least one further set of conditions; andd) using the model to predict retention times for conditions other than those of step a;the apparatus composed of a data handling system including a model for predicting retention times at a variety of conditions of operation of the system, the model having a first set of inputs including ret

Abstract: In a spectrophotometer, each of a plurality of source optical fibers is selectively receptive of source radiation and carries the radiation to a corresponding selected liquid sample cell. A corresponding return optical fiber returns transmitted radiation from the sample to a polychromator. For selecting a sample, a switching member holds exposed ends of the optical fibers on a circle coaxial with an axle for rotating to selected positions. Respective optical trains in the instrument direct radiation into and out of the selected pair of fibers. The diameter of a source aperture, the spacing of the aperture from the radiation source, and the source area define a source etendue. The optical fibers have a fiber etendue substantially the same as the source etendue.

Abstract: An optical switch includes a primary optical fiber terminating in a primary window, and a plurality of secondary optical fibers each terminating in a secondary window facing in the same direction as and spaced laterally from the primary window. A primary lens on a primary axis has a focal point positioned on the axis at the central window. Each of a plurality of secondary lenses has an axis and a focal point positioned on such axis at a secondary window. The secondary axes are parallel to and equidistant from the primary axis. A retroreflector is spaced from the lenses oppositely from each window and has an optical axis centered parallel to the primary axis midway between the primary axis and any of the secondary fibers. A stepper motor rotates the retroreflector about the primary axis to each of a plurality of selected positions to provide optical switching for light transmission between the primary fiber and any selected secondary fiber.

Abstract: A method and apparatus for the identification and quantification of a vapor, or a number of vapors, in air mixtures is discussed. The method includes calibration of a vapor responsive sensor, or a plurality of vapor responsive sensors, to known concentrations of the vapors of interest or to known concentrations of potential interfering vapors. The calibrations result in sensor response vectors which are derived from the transient signals observed as the vapors are sorbed and desorbed on the sensors. Detection of vapors in complex mixtures is effected by subjecting the apparatus to the mixture and measuring the sensor response, or plurality of sensor responses, and then applying multidimensional statistical analysis or filtering methods to this data, using the precalibrated response vectors as the basis set for deconvolution.

Abstract: In a spectrophotometer, each of a plurality of source optical fibers is selectively receptive of source radiation and carries the radiation to a corresponding selected liquid sample cell. A corresponding return optical fiber returns transmitted radiation from the sample to a polychromator. For selecting a sample, a switching member holds exposed ends of the optical fibers on a circle coaxial with an axle for rotating to selected positions. Respective optical trains in the instrument direct radiation into and out of the selected pair of fibers. The diameter of a source aperture, the spacing of the aperture from the radiation source, and the source area define a source etendue. The optical fibers have a fiber etendue substantially the same as the source etendue.

Abstract: Spectral bands are grouped for data acquisition in a spectrophotometer with a charge-coupled detector having a plurality of pixels. Preliminary data is generated on time-integrated radiation to the pixels for a sample. Maximum permitted exposure times for the pixels are calculated from the data and a predetermined maximum exposure. The maximum times are grouped so that for each group the ratio of the highest to the lowest maximum times is less than 100. A group run time is established for each group nominally less than the lowest maximum time in the group. Subgroups are created and ordered so that accumulated readout times for the pixels are less than wait times established to prevent readout contamination from subsequent charge buildup. The spectrophotometer is further operated on the sample for the run time of each group and subgroup to generate spectral data.

Abstract: A method for determining concentration of an analyte in a sample includes generating a spectrum of a selected analyte and interferents, generating a spectrum of an unknown sample, computing first and second derivatives of the sample spectrum, deriving a matrix model that includes the analyte spectrum and the derivatives, and applying the matrix model to the sample spectrum so as to yield a parameter representing concentration of the selected analyte in the unknown sample. Multiple linear least squares regression is utilized to fit the model and calculate the parameter.

Abstract: A spectrometric instrument which exhibits an intrinsic profile for a sharp spectral line produces profile data for narrow spectral lines. The spectral lines are effected with a high finesse etalon of gold coated polymer. A transformation filter is computed for transforming the profile data to a gaussian profile. A wavelength calibration is combined with the filter to effect a correction matrix which is applied to sample data to generate calibrated standardized data. Iteratively a correction matrix is applied to calibration data to generate standardized calibration data which is utilized for the wavelength calibration. Calibration is effected with an optical standard, an interference etalon and a fringe formula. Etalon effective thickness is first estimated and then precisely determined so that fringe peaks calibrate wavelength.

Abstract: To calibrate a photodetector, a rotating disk with a slot is disposed in a light beam with decreasing speed from a defined maximum rotational speed to a defined minimum speed, while magnitudes and times of signals are read out and stored. Vernier pairs of signals occur in adjacent readout intervals, and non-vernier signals exclude the verniers. Readout times for verniers are used to estimate a preliminary function of rotations versus time. From the function are estimated an occurrence time for each pair and period of disk rotation at the time. Vernier fraction is the ratio of one signal in the pair to the sum of the pair. A time offset is the product of vernier fraction, slot fraction of the disk and the estimated period. Occurrence times corrected with the time offset are utilized to fit a corrected function of disk rotations versus time. Points of time for the non-vernier signals are determined from the corrected function, each point corresponding to disk rotations to a corresponding non-vernier signal.

Abstract: A photolithography exposure control system tolerant of noisy pulsed light sources having a controllable variable attenuator. A detector monitors the exposure dose of a light pulse enabling a controller to trigger another light pulse, when a predetermined attenuator is positioned in its path. A high degree of exposure control is achieved with a minimum number of light pulses or shots.

Abstract: A Rowland circle-type polychromator with the Rowland circle arc pivotally connected to the concave grating. Separate adjustments are provides for shifting the spectral lines and focussing. A tie rod is used to adjust the focus of the spectral lines. Dectectors are predeterminedly spaced along the arc to simultaneously detect unique spectral lines for analysis of multiple elements contained in a single sample.

Abstract: An apparatus for monitoring a plasma torch includes a dedicated photometer which produces a signal representative of the temperature of a quartz tube of the torch, which signal can be used to reduce the temperature thereof.

Abstract: A plasma etching system includes a grounded reactor chamber having ungrounded chuck and counter electrodes therein. Circuitry is provided so that the potentials applied to the electrodes are about half those normally applied in single ended systems so that stray electrical discharges from the electrodes to the reactor chamber and other parts in the system are minimized.

Abstract: A relatively small amount of high frequency RF power is mixed with a predominantly low frequency RF power to provide an improved etch rate uniformity of a semiconductor wafer in a low frequency plasma etching system.

Abstract: Pressurized gas is applied between a wafer and electrode in a plasma etching system. Gas between the wafer and electrode provides cooling of the wafer. A control arrangement maintains the gas at a predetermined pressure.

Abstract: An electrode includes a plurality of nested concentric rings forming plenum chambers. Process gas is fed into the plenum chambers through capillary tubes. The gas is then delivered through slits between the rings into a plasma etching reactor.