213results about "Multiplier circuit arrangements" patented technology

The present invention provides a gamma-neutron detector based on mixtures of thermal neutron absorbers that produce heavy-particle emission following thermal capture. The detector consists of one or more thin screens embedded in transparent hydrogenous light guides, which also serve as a neutron moderator. The emitted particles interact with the scintillator screen and produce a high light output, which is collected by the light guides into a photomultiplier tube and produces a signal from which the neutrons are counted. Simultaneous gamma-ray detection is provided by replacing the light guide material with a plastic scintillator. The plastic scintillator serves as the gamma-ray detector, moderator and light guide. The neutrons and gamma-ray events are separated employing Pulse-Shape Discrimination (PSD). The detector can be used in several scanning configurations including portal, drive-through, drive-by, handheld and backpack, etc.

A fusion night vision system having image intensification and thermal imaging capabilities includes an edge detection filter circuit to aid in acquiring and identifying targets. An outline of the thermal image is generated and combined with the image intensification image without obscuration of the image intensification image. The fusion night vision system may also include a parallax compensation circuit to overcome parallax problems as a result of the image intensification channel being spaced from the thermal channel. The fusion night vision system may also include a control circuit configured to maintain a perceived brightness through an eyepiece over a mix of image intensification information and thermal information. The fusion night vision system may incorporate a targeting mode that allows an operator to acquire a target without having the scene saturated by a laser pointer. The night vision system may also include a detector, an image combiner for forming a fused image from the detector and a display, and a camera aligned with image combiner for recording scene information processed by the first detector.

Methods and means for measuring and adjusting the gain of a photomultiplier tube (PMT), or other photo-detector with electron multiplication gain, for the purpose of achieving accurate light measurement, such as in a luminescent radiation dosimeter reader. With a PMT illuminated by a light emitting diode or other light source, the PMT output signal is measured in two modes, signal integration and photon pulse counting. The measured PMT gain is calculated as the ratio of the integrated signal to the photon pulse count. The PMT high voltage may be adjusted to cause the measured PMT gain to correspond to an established calibration gain value, or the data from the PMT may be adjusted to compensate the deviation of the measured PMT gain from the calibration gain value. The light source may be a controllable light source that can be adjusted to provide a specific photon count rate output as measured by the PMT. This invention provides for maintaining light measurement calibration without requiring temperature stabilization or a fixed light source.

A light sensing circuit of a touch panel includes a photodiode including an anode and a cathode; a driving transistor including a gate electrode connected to the cathode of the photodiode, a first electrode to receive a first ground voltage, and a second electrode; a first switching transistor including a first electrode connected to the second electrode of the driving transistor, a second electrode to output a data signal, and a gate electrode to receive a scan signal; a first capacitor including a first terminal connected to the cathode of the photodiode, and a second terminal; and a voltage compensating unit to apply a compensation voltage to the second terminal of the first capacitor.

An improved electron multiplier bias network that limits the response of the multiplier when the multiplier is faced with very large input signals, but then permits the multiplier to recover quickly following the large input signal. In one aspect, this invention provides an electron multiplier, having a cathode that emits electrons in response to receiving a particle, wherein the particle is one of a charged particle, a neutral particle, or a photon; an ordered chain of dynodes wherein each dynode receives electrons from a preceding dynode and emits a larger number of electrons to be received by the next dynode in the chain, wherein the first dynode of the ordered chain of dynodes receives electrons emitted by the cathode; an anode that collects the electrons emitted by the last dynode of the ordered chain of dynodes; a biasing system that biases each dynode of the ordered chain of dynodes to a specific potential; a set of charge reservoirs, wherein each charge reservoir of the set of charge reservoirs is connected with one of the dynodes of the ordered chain of dynodes; and an isolating element placed between one of the dynodes and its corresponding charge reservoir, where the isolating element is configured to control the response of the electron multiplier when the multiplier receives a large input signal, so as to permit the multiplier to enter into and exit from saturation in a controlled and rapid manner.

A low-light viewing device includes a housing, having mounted thereto: a lens, an electronic camera for receiving light focused by the lens and for providing an output signal; a display for receiving the output signal and displaying an image detected by the camera; a controller for controlling the camera and the display, and a user interface for operating the controller. The lens may be a fixed focus lens having an F number of less than about 1, and a T number of less than about 1.5. The display may have a resolution at least as great as the resolution of the camera. The device may have a processor programmed to provide control signals to the camera and display depending on a selected light environment.

A fusion vision system has a first sensor configured to detect scene information in a first range of wavelengths, a second sensor configured to detect scene information in a second range of wavelengths, and a processor configured to resize one of a first and a second image to improve viewability of the fused scene.

A low-photon flux image-intensified electronic camera comprises a gallium arsenide phosphide (GaAsP) photocathode in a high vacuum tube assembly behind a hermetic front seal to receive image photons. Such is cooled by a Peltier device to −20° C. to 0° C., and followed by a dual microchannel plate. The microchannels in each plate are oppositely longitudinally tilted away from the concentric to restrict positive ions that would otherwise contribute to the generation high brightness “scintillation” noise events at the output of the image. A phosphor-coated output fiberoptic conducts intensified light to an image sensor device. This too is chilled and produces a camera signal output. A high voltage power supply connected to the dual microchannel plate provides for gain control and photocathode gating and shuttering. A fiberoptic taper is used at the output of the image intensifier vacuum tube as a minifier between the internal output fiberoptic and the image sensor.

A compact integrated APD device integrates the bias voltage and temperature compensation functions inside a standard 4-pin PIN package. The active components of the bias and temperature compensation circuits are integrated into a single ASIC using a high-voltage CMOS process and operated at frequencies of at least 1 MHz to greatly reduce the size of the passive components. To mount the relatively large ASIC chip inside the package with the APD chip, TIA chip and passives, the 4-pin package may be modified by either recessing the pins inside the can to facilitate surface mounting the ASIC or adding a spacer inside the can to facilitate three-dimensional packaging. Communication with the bias and temperature circuits is accomplished using a unique bi-directional 1-wire serial interface via the power supply pin. A clock signal is preferably embedded in the control data to synchronize the APD with an external controller.

An electron sensing device for receiving electrons from an output surface of an electron gain device has a silicon die including an active surface area for positioning below the output surface of an electron gain device. The silicon die also includes a silicon step formed below and surrounding the active surface area, and a first array of bond pads formed on the silicon step for providing output signals from the silicon die. When the electron sensing device is positioned below the electron gain device, a tight vertical clearance is formed between the output surface of the electron gain device and the active surface area of the electron sensing device.

Switching uniformity of an optical modulation device for controlling the propagation of electromagnetic radiation is improved by use of an electrode comprising an electrically resistive layer that is transparent to the radiation. The resistive layer is preferably an innerlayer of a wide-bandgap oxide sandwiched between layers of indium tin oxide or another transparent conductor, and may be of uniform thickness, or may be graded so as to provide further improvement in the switching uniformity. The electrode may be used with electrochromic and reversible electrochemical mirror (REM) smart window devices, as well as display devices based on various technologies.

Plural electronic or optical images are provided in a streak optical system, as for instance by use of plural slits instead of the conventional single slit, to obtain a third, fourth, etc. dimension—rather than only the conventional two, namely range or time and azimuth. Such additional dimension or dimensions are thereby incorporated into the optical information that is to be streaked and thereby time resolved. The added dimensions may take any of an extremely broad range of forms, including wave-length, polarization state, or one or more spatial dimensions—or indeed virtually any optical parameter that can be impressed upon a probe beam. Resulting capabilities remarkably include several new forms of lidar spectroscopy, fluorescence analysis, polarimetry, spectropolarimetry, and combinations of these, as well as a gigahertz wavefront sensor.

The night vision camera system includes a light, a night vision camera, and a linkage. The night vision camera is attached to the light such that the light and camera maintain a fixed orientation with respect to each other. The light is attached to the linkage and is configured to manipulate the light and night vision camera concurrently. The linkage is attached to the vehicle and extends into the vehicle interior where a handle is provided allowing the user to aim the light and night vision camera from the interior of the vehicle.

An intensified solid-state imaging sensor includes a photo cathode for converting light from an image into electrons, an electron multiplying device for receiving electrons from the photo cathode, and a solid-state image sensor including a plurality of pixels for receiving the electrons from the electron multiplying device through a plurality of channels of the electron multiplying device. The solid-state image sensor generates an intensified image signal from the electrons received from the electron multiplying device. The plurality of channels are arranged in a plurality of channel patterns, and the plurality of pixels are arranged in a plurality of pixel patterns. Each of the plurality of channel patterns is mapped to a respective one of the plurality of pixel patterns such that electron signals from each of the plurality of channel patterns is substantially received by the single respective one of the plurality of pixel patterns.

The present invention provides a gamma-neutron detector based on mixtures of thermal neutron absorbers that produce heavy-particle emission following thermal capture. The detector consists of one or more thin screens embedded in transparent hydrogenous light guides, which also serve as a neutron moderator. The emitted particles interact with the scintillator screen and produce a high light output, which is collected by the light guides into a photomultiplier tube and produces a signal from which the neutrons are counted. Simultaneous gamma-ray detection is provided by replacing the light guide material with a plastic scintillator. The plastic scintillator serves as the gamma-ray detector, moderator and light guide. The neutrons and gamma-ray events are separated employing Pulse-Shape Discrimination (PSD). The detector can be used in several scanning configurations including portal, drive-through, drive-by, handheld and backpack, etc.

A voltage divider network in combination with a voltage multiplier circuit voltage biases the electrodes of a photomultiplier tubes or related device. The circuit exploits the several voltage levels produced at successive stages of a voltage multiplier circuit in order to optimize the voltage divider network with respect to power consumption, current draw from the power supply, operating stability, and linear operation of the photomultiplier tube.

The present invention provides a gamma-neutron detector based on mixtures of thermal neutron absorbers that produce heavy-particle emission following thermal capture. In one configuration, B-10 based detector is used in a parallel electrode plate geometry that integrates neutron moderating sheets, such as polyethylene, on the back of the electrode plates to thermalize the neutrons and then detect them with high efficiency. The moderator can also be replaced with plastic scintillator sheets viewed with a large area photomultiplier tube to detect gamma-rays as well. The detector can be used in several scanning configurations including portal, drive-through, drive-by, handheld and backpack, etc.

Automatic control method and system for EBCCD sensor. The invention relates to a novel protective method of operating the Electron Bombarded Charge Coupled Device (EBCCD), a recently developed, high sensitivity, low noise, and expensive focal plane array sensor. In particular, the invention provides a method for operation that automatically controls the EBCCD gain at a very high rate. This allows i) for sensor damage protection from too much light, ii) for extension of sensor service life by reducing gain in periods of non-use, and iii) for automatic gain adjustment to rapidly compensate for variations in scene brightness.

An electrical circuit for a photomultiplier tube (PMT) is disclosed that reduces power consumption to a point where the PMT may be powered for extended periods with a battery. More specifically, the invention concerns a PMT circuit comprising a low leakage switch and a high voltage capacitor positioned between a resistive divider and each of the PMT dynodes, and a low power control scheme for recharging the capacitors.

An advanced image intensifier assembly provides enhanced functionality. A grounded photocathode provides shielding from electromagnetic interference, improving the ability to work in multiple light conditions. Bi-directional wireless communication and non-volatile storage allow critical information to be permanently stored and read wirelessly at a scanning station, easing in identification of units. Because bi-directional communication components can be embedded within an image intensifier assembly, existing end-user night vision devices can be upgraded by simply replacing the image intensifier assembly. For enhanced safety, a programmable shutdown capability is provided. This renders the device inoperative in the absence of continuous input, either wireless or manual, from an authorized operator, thus rendering the device useless if captured by enemy combatants. Finally, direct 1-volt operation enables the device to be powered by, for example, a single AA battery.

In an ion detector, power supplies (21 through 23) generating independently controllable voltages are provided to respectively apply voltages to first to fifth dynodes (11 through 15), a final dynode (16), and an anode (17) in a secondary electron multiplier (10). Furthermore, the signal from the anode (17) is extracted, and the signal from the fifth dynode (15), which has a low electron multiplication rate, is extracted. These two signals are concurrently converted into digital values, taken in by a data processing unit (34), and stored in a data storage unit (35). When a mass spectrum is created in the data processing unit (34), the two detected data for the same time are read out and the presence or absence of signal saturation or waveform deformation is determined from the values of one of the detection data. If there is a high probability of signal saturation, the detection data based on the signals in the intermediate stages are selected, and the level of the selected data is corrected. The application of independent voltages to the secondary electron multiplier (10) makes the signal saturation less likely to occur. Even if saturation temporarily occurs, an unsaturated signal can be reflected in the mass spectrum.

A novel electron multiplier that regulates in real time the gain of downstream dynodes as the instrument receives input signals is introduced. In particular, the methods, electron multiplier structures, and coupled control circuits of the present invention enable a resultant on the fly control signal to be generated upon receiving a predetermined threshold detection signal so as to enable the voltage regulation of one or more downstream dynodes near the output of the device. Accordingly, such a novel design, as presented herein, prevents the dynodes near the output of the instrument from being exposed to deleterious current pulses that can accelerate the aging process of the dynode structures that are essential to the device.

A fiber optic interrogator includes a broadband optical source, at least one beam splitter directing output of the optical source to an array of fiber optic gratings, at least one linear transmission or reflection filter, at least one optical receiver and at least one amplifier associated with each receiver. In one aspect of the invention, a linear transmission filter is used to convert the change in center wavelength of a grating reflectivity spectrum to a change in intensity, which is proportional to the change in the grating central wavelength. In another aspect of the invention, a pair of opposite-sloped linear transmission filters are utilized to normalize the received and filtered reflections with respect to total optical power. In another aspect of the invention, the optical source is pulsed, and return pulses from each fiber optic grating to be measured are sampled by the interrogator at different times. In another aspect of the invention, the source driver randomizes ripple phase versus wavelength to reduce wavelength measurement error. In another aspect of the invention, active closed-loop circuits are added to the receiver amplifiers to stabilize the amplifier output. In yet another aspect of the invention, a temperature-controlled compensating array of fiber optic gratings is interrogated each time the measurement array of gratings is interrogated. In still another aspect of the invention, a fast reset analog integrator is added to the amplifier stage(s) to improve the signal detection threshold. In another aspect of the invention, the wavelength measurement is compensated for the effects of one grating shading another.

According to the present invention, a photomultiplier tube is used with a high-speed feedback mechanism to continuously modulate the gain of the tube in response to the size of the input signal. The gain of the tube and the anode current are independently converted to ideal logarithms. These signals are then subtracted from one another to reconstruct a true logarithmic representation of the optical signal. This log-light-level signal has a higher dynamic range and faster temporal response than has previously been achieved by other methods.

An apparatus and method for displaying an image of a subject in low light conditions. The image is displayed on a video screen. The image is viewed through an eyepiece to reduce the amount of light illuminating a user's face while observing the subject. In an embodiment, the eyepiece is monocular to prevent night blindness in at least one eye. In an embodiment, the video screen is disposed within the housing of the night vision device. In an embodiment, a user can selectively filter the light emitted by the display screen to change its color or to reduce the amount of light received by the user's eye.

A day / night weapon sight assembly that consists of daytime sight and a nighttime sight allows the use of both sights without change in eye relief even when the nighttime sight is attached to the rear end of the daytime sight. This is achieved by supporting the daytime sight moveably in the direction of the optical axis and by supporting the nighttime sight with the use of a plane-parallel motion mechanism that allows switching of the nighttime sight between the upper inoperative position and the operative position behind and coaxially with the daytime sight.

Inspection systems, circuits and methods are provided to enhance defect detection by addressing saturation levels of the amplifier and analog-digital circuitry as a limiting factor of the measurement detection range of an inspection system. In accordance with one embodiment of the invention, a method for inspecting a specimen includes directing light to the specimen and detecting light scattered from the specimen. However, the step of detecting may use only one photodetector for detecting the light scattered from the specimen and for converting the light into an electrical signal. The step of detecting also includes generating a first signal and a second signal in response to the electrical signal, where the second signal differs from the first. For example, the first signal may be generated to have a higher resolution than the second signal for detecting substantially lower levels of the scattered light. In most cases, the method may use the first signal for detecting features, defects or light scattering properties of the specimen until the first signal reaches a predetermined threshold value. Once the predetermined threshold value is reached, however, the method may use the second signal for said detecting.

Methods and systems for inspecting rotatable machine components are provided. The system includes a fiber optic port configured to extend through a first aperture of a machine casing wherein the port includes an interior end and an exterior end. The system further includes an imager configured to optically couple to the exterior end. The imager includes a light intensifier capable of generate images of inspection components though the port using ambient light. The imager further includes an image capture gate configured to control an acquisition time of the generated images.

A light sensor circuit based on direct connection of LEDs to I / O pins of a microcontroller. The LEDs are reverse biased and the parasitic junction capacitance is charged in an output mode. Then, the I / O pins placed into an high-impedance input mode. The time for the capacitance to be discharged by photoconduction caused by light incident on the LEDs is inversely proportional to an intensity of the incident light, and can be directly measured as the time required for the I / O pin to transition from fully-charged (5 volts) to a logic threshold level (1.7 volts). By using multiple LEDs, multiplexed between emissive and sensing modes, a wide variety of sensors can be constructed, particularly, when the LEDs emit light at different wavelength.