Abstract:
The present invention provides a simple, robust, and versatile high-resolution spectrometer that is suitable for downhole use. The present invention provides a method and apparatus incorporating a spinning, oscillating or stepping optical interference filter to change the angle at which light passes through the filters after passing through a sample under analysis downhole. As each filter is tilted, the color or wavelength of light passed by the filter changes. Black plates are placed between the filters to isolate each filter's photodiode. The spectrometer of the present invention is suitable for use with a wire line formation tester, such as the Baker Atlas Reservation Characterization Instrument to provide supplemental analysis and monitoring of sample clean up. The present invention is also suitable for deployment in a monitoring while drilling environment. The present invention provides a high resolution spectometer which enables quantification of a crude oil's percentage of aromatics, olefins, and saturates to estimate a sample's gas oil ratio (GOR). Gases such as CO2 are also detectable. The percentage of oil-based mud filtrate contamination in a crude oil sample can be estimated with the present invention by using a suitable training set and chemometrics, a neural network, or other type of correlation method.
Abstract:
An apparatus and method of analyzing phases of a multi-phase mixture allows an analysis of a mixture that has great turbidity or is opaque. An emission device emits electromagnetic radiation in a direction of a measurement cell. The electromagnetic radiation is back scattered by the mixture and is detected by a primary detection device. A secondary detection device may detect electromagnetic radiation that is transmitted but is not back scattered by the mixture. A moving device displaces the primary detection device in order to carry out a plurality of detections at a predetermined step over the length of the measurement cell. The scanning of the cell allows one to obtain a cycle of measurements that produces a phase profile of the mixture.
Abstract:
A multistage interconnect network (MIN) capable of supporting massive parallel processing, including point-to-point and multicast communications between processor modules (PMs) which are connected to the input and output ports of the network. The network is built using interconnected switch nodes arranged in 2 log.sub.b N stages, wherein b is the number of switch node input/output ports, N is the number of network input/output ports and log.sub.b N indicates a ceiling function providing the smallest integer not less than log.sub.b N. The additional stages provide additional paths between network input ports and network output ports, thereby enhancing fault tolerance and lessening contention.
Abstract:
The present invention is a scanning monochromator for producing a light beam which rapidly and repetitively varies in wavelength. The device is a subtractive double monochromator in which an intermediate slit is moved to effect wavelength scanning; the intermediate slit fitted in a rotating disk positioned at the intermediate focal plane of the monochromator. Two forms of the device are disclosed.
Abstract:
A method and apparatus for determining the characteristics of materials, particularly of semi-conductors, semi-conductor heterostructures and semi-conductor interfaces by the use of photoreflectance, in which monochromatic light and an acousto-optically modulated light beam reflected from the sample is detected to produce a d.c. signal and an a.c. signal, whereby the d.c. signal is applied to one input of a computer and the a.c. signal is used with another input of the computer which controls the light intensity of the monochromatic light impinging on the sample to maintain the d.c. signal substantially constant. The modulation frequency of the modulated pump beam and/or the wavelength of the monochromatic light can also be varied by the computer. Information about trap times can be obtained by determining the dependence of the in-phase signal on the pump modulating frequency, respectively.
Abstract:
The invention relates to a spectrometry installation comprising an inlet, optical fiber means suitable for receiving an inlet beam and delivering a spectrally dispersed image of the beam which image is limited to a selected spectral band, a multi-channel detection module receiving said spectral image, and processor means. The optical filter means are provided with a deflector stage. Control means are associated with the optical deflector means to define the spectral band in terms of center frequency and band width, and control means are associated therewith for displacing the spectral image over the detection module. An electronic control unit is provided to control the control means and to control the processor means in a plurality of operating modes, each of which comprises joint control of the selected spectral band, of the displacement of the spectral image, and of the processor means, for the purpose of selectively using a particular set of detector components.
Abstract:
In its preferred embodiment, a scanning monochromator uses a pulse-driven micro-stepping motor to drive a spectral-dispersion element via a reduction-gear harmonic drive. The motor is directly coupled to the input hub of the reduction-gear drive, and the output hub of the reduction-gear drive directly supports the spectral-dispersion element. By selecting a motor with a great number of steps per revolution, and a harmonic drive with a great reduction ratio, a resolution of 5 million pulsed steps is available, per single rotation of the output hub of the reduction-gear drive. This translates into more than 600,000 incremental angular-displacement steps over a usable 45.degree. range of dispersion-element rotation.
Abstract:
Output data from a spectrophotometer may be presented as a series of data values representative of the intensity amplitude of pass bands having equal bandwidths (resolution) and spaced at wavelength intervals equal to the bandwidth. For some purposes it is desirable to increase the bandwidth of said data, and this invention discloses method and apparatus for converting such data to equivalent data having a selected greater bandwidth.
Abstract:
System and method for analyzing spectral data from an optical fiber waveguide. Light from the waveguide is directed to a diffraction grating which separates the light into its spectral components and directs these components toward a light responsive detector. The grating is rotated to cause spectral components of different wavelengths to sweep across the detector, and a sensor provides a signal corresponding to the angular position of the grating. A table of calibration data is generated by introducing monochromatic light of known wavelength into the waveguide, positioning the grating to cause the light at two known points in the spectrum of the monochromatic light to impinge upon the detector, and utilizing the wavelength of the monochromatic light and the values of the sensor signal at the two known points to define the relationship between the sensor signal and the detected wavelength for a plurality of grating positions. The calibaration data and the sensor signal are utilized to determine the wavelength of light peaks produced by a sample, and they are also utilized to generate a control signal for positioning the grating very accurately to detect light of a given wavelength. In one disclosed embodiment, two detectors having different spectral responses are employed, and light in different portions of the spectrum is detected by respective ones of the detectors.
Abstract:
A method and apparatus for controlling the spectral components of a light beam are described. The apparatus comprises means (3-7) for generating a collimated light beam; means (9) for dispersing the collimated beam; a mask (1) including an aperture (2) the size of which is such that a portion of the dispersed beam passes through the aperture in use; and movement means (not shown) for causing relative transverse movement between the light beam and the aperture. A memory (not shown) is provided for storing in use a profile of the relative transverse movement between the light beam and the aperture (2) required to obtain a desired spectral response in the transmitted light beam, the movement means being responsive to the stored profile to cause relative transverse movement in accordance with the predetermined profile.