Abstract: A thermal shunt apparatus directs heat flux transmitted through electrical signal leads from a focal plane array (FPA) to a relatively isothermal top surface of a TE cooler. The FPA mounts with a first thermally conductive attachment to a thermal spreader plate that is highly thermally conductive. The thermal spreader plate is mounted to the top surface of the TE cooler by a second thermally conductive attachment. The combination of the relatively isothermal surfaces, the FPA thermal spreader and the TE cooler top plate, separated by the thermally conductive interface, maintains a relatively constant temperature difference between the electrical leads connected between the thermal shunt and the FPA edge. The constant temperature difference provides for constant heat flux between these points and a constant temperature gradient across the surface of the FPA.

Abstract: A double direct injection dual band focal plane array input circuit provides simultaneous and separate integration of the current from two sensors which share a common node. The sensors are constant voltage and variable current sensors such as HgCdTe infrared photodiodes. The sensor voltage biases are independently adjustable. Multiple integration of the signal from one sensor may be performed within one integration time of the other sensor. The circuit is used in staring infrared dual band focal plane arrays and may be used process information from more than two sensors.

Abstract: An extreme wide angle, very large aperture, very compact, solar blind, UV imaging lens system. The lens system has a fused silica polyvinyl alcohol glass color filter, a lens made of fused silica, a lens made of nickel sulfate, a layer of coupling fluid and another lens made of fused silica. Alternatively, sapphire can be used after the color filter instead of the fused silica. An alternative lens is composed of two layers of fused silica, a layer of nickel sulfate, another layer of fused silica, coupling fluid followed by polyvinyl alcohol, a color glass filter and coupling fluid followed by fused silica. In a fourth embodiment, the two layers of fused silica are followed by polyvinyl alcohol, a layer of colored glass filter, fused silica, nickel sulfate, coupling fluid, and fused silica.

Abstract: A data acquisition and display apparatus for an ultrasonic camera includes an ultrasonic scanning head for scanning an ultrasonic field of view in two dimensions. A timing and digitizing apparatus for digitizing ultrasonic signals from the ultrasonic scan head has a digitized output. An interface is coupled between the timing and digitizing apparatus and a graphics engine and first and second digital signal processors. A graphics processor is coupled to the graphics data line. The system also includes an image processor and computer controller which controls the graphics and digital signal processors.

Abstract: An integrated optical system illuminates an ultraviolet spatial detector with an image from a field of interest. The ultraviolet spatial detector is comprised of an electron multiplying microchannel plate and a 100 pixel discrete anode array using a high strip current microchannel plate. The discrete anode array preserves the spatial distribution of the image. The ultraviolet spatial sensor has a wide field of view. The ultraviolet spatial detector has a photon counting sensor capable of detecting ultraviolet sources to determine their position to within plus or minus 4.5 degrees.

Abstract: An analog signal processing circuit used to suppress unipolar transient effects and signal averaging. Two transistors and one capacitor are provided in series to sample and condition an input signal. An additional transistor is provided in parallel to the capacitor to provide further signal processing capabilities. The circuit can function as an analog signal average, suppressing unipolar transient effects and as a peak detector while using a conservative amount of fabrication material and can be operated with low power.

Abstract: A monolithic detector array apparatus for sensing infrared radiation. An array of semiconductor diode bolometers are fabricated on micromachined thermal isolation structures called microbridges. The detectors are configured in an array and addressed by row and column. Readout circuitry may be optionally incorporated onto a common substrate. The monolithic detector array may be highly integrated, resulting in a low cost and a high performance focal plane array.

Abstract: A two color radiation detector. A dispersive lens with a spectrally selective central obscuration focuses a first radiation band on a central location on focal plane array. The dispersive lens also focuses an annulus of out of focus radiation of a second radiation band concentric with the central location on the focal plane array. For point target detection the dispersive lens transmits plume band and guard band radiation to the staring focal plane array sensor. The staring focal plane array is located at the focal point of the plume band radiation. A spatial filter detects target signatures using information from the plume band and guard band radiation.

Abstract: Autocorrelation processing finds a series of equally spaced pulses and noise. Pulses that are very narrow with inter-pulsed durations of several hundred times the width of the pulse are processed. A threshold detector receives an input from a sensor, the sensor providing the pulses. The threshold detector enables a flip flop which receives the output of a free running counter. The output of the free running counter is sent to a buffer such as, for example, a first in, first out circular buffer. The events held in the buffer are processed later for further autocorrelation processing.

Abstract: An overload protection circuit for a photomultiplier tube. A light source illuminates a photomultiplier tube which produces a signal proportional to the incoming radiation which is sent to photon counting electronics. The photon counting electronics produces a signal in proportion to the input photons to the photomultiplier tube and also provides an output to a frequency to voltage converter. The frequency to voltage converter is used to modulate a high voltage amplifier which controls the output of the photomultiplier tube. When the photon counting electronics indicate to the frequency to voltage converter that the photons produced by the photomultiplier tube exceed a predetermined maximum the high voltage amplifier reduces the gain of the photomultiplier tube. The gain of the photomultiplier tube is gradually reduced in proportion to the incident light level.

Abstract: This invention provides a method for fabricating buttable infrared detector arrays by dimensionally controlled cleaving of a single crystal wafer substrate having well defined cleavage planes. The single crystal wafer substrate is first cleaved along its natural cleavage planes so as to form a plurality of cleavage lines defining rectangular detector array regions. A layer of infrared sensitive material is epitaxially grown on the cleaved single crystal wafer substrate. Infrared detector arrays are fabricated on the layer of infrared sensitive material within the rectangular detector array regions defined by the cleavage lines on the single crystal wafer substrate. The fabricated infrared detector arrays are then separated at the cleavage lines so as to form individual buttable infrared detector arrays.