2002 results about "Photomultiplier" patented technology

A gaseous fluorine detection system is provided which includes a generally enclosed sample cell containing a substrate comprising a material which interacts with fluorine gas to generate radiant energy. A gas sample of fluorine, the concentration levels of which are to be evaluated is flowed through the cell. A photomultiplier tube is positioned to receive the resulting radiant energy and generate an electrical output signal related to the level of said radiant energy. Means are provided for measuring the said photomultiplier output signal and relating same to the fluorine concentration of the gas sample provided to the cell.

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 method and apparatus for measuring electrochemiluminescence from a sample composition are described wherein magnetically responsive electrochemiluminescent active species are captured on the electrode with the aid of a capture magnet having a configuration such that the magnetic flux lines (or the magnetic field gradient) of at least one magnetic field source therein are compressed and/or dispersed. This capture magnet improves the distribution of the magnetically responsive electrochemiluminescent active species on the electrode surface and reduces interference with the photomultiplier tube, thereby enhancing the ECL signal and improving sensitivity. The improved capture and distribution also allows for shorter assay times.

A radiation detector includes an array of detector pixels each including an array of detector cells. Each detector cell includes a photodiode biased in a breakdown region and digital circuitry coupled with the photodiode and configured to output a first digital value in a quiescent state and a second digital value responsive to photon detection by the photodiode. Digital triggering circuitry is configured to output a trigger signal indicative of a start of an integration time period responsive to a selected number of one or more of the detector cells transitioning from the first digital value to the second digital value. Readout digital circuitry accumulates a count of a number of transitions of detector cells of the array of detector cells from the first digital state to the second digital state over the integration time period.

An electron detector includes a plurality of assemblies, the plurality of assemblies including a first assembly having a first SiPM and a first scintillator made of a first scintillator material directly connected to an active light sensing surface of the first SiPM, and a second assembly having a second SiPM and a second scintillator made of a second scintillator material directly connected to an active light sensing surface of the second SiPM, wherein the first scintillator material and the second scintillator material are different than one another. Alternatively, an electron detector includes an assembly including an SiPM and a scintillator member having a front surface and a back surface, the scintillator member being a film of a scintillator material directly deposited on to an active light sensing surface of the SiPM.

A solid-state photomultiplier (SSPM) includes an optical isolation structure therein. The SSPM includes a substrate and an epitaxial diode layer positioned on the substrate. A plurality of avalanche photodiodes (APDs) are fabricated on the epitaxial diode layer and the optical isolation structure is positioned about the plurality of APDs to separate each of the plurality of APDs from adjacent APDs. The optical isolation structure contains at least one of a light absorbing material and a light reflecting material deposited therein to reduce optical crosstalk and dark count rate in the SSPM.

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 method and apparatus for producing with a gas discharge laser an output laser beam comprising output laser light pulses, for delivery as a light source to a utilizing tool is disclosed which may comprise a beam path and a beam homogenizer in the beam path. The beam homogenizer may comprise at least one beam image inverter or spatial rotator, which may comprise a spatial coherency cell position shifter. The homogenizer may comprise a delay path which is longer than, but approximately the same delay as the temporal coherence length of the source beam. The homogenizer may comprise a pair of conjoined dove prisms having a partially reflective coating at the conjoined surfaces of each, a right triangle prism comprising a hypotenuse face facing the source beam and fully reflective adjoining side faces or an isosceles triangle prism having a face facing the source beam and fully reflective adjoining side faces or combinations of these, which may serve as a source beam multiple alternating inverted image creating mechanism. The beam path may be part of a bandwidth measuring the bandwidths of an output laser beam comprising output laser light in the range of below 500 femtometers at accuracies within tens of femtometers. The homogenizer may comprise a rotating diffuser which may be a ground glass diffuser which may also be etched. The wavemeter may also comprise a collimator in the beam path collimating the diffused light; a confocal etalon creating an output based upon the collimated light entering the confocal etalon; and a detector detecting the output of the confocal etalon and may also comprise a scanning mechanism scanning the angle of incidence of the collimated light entering the confocal etalon which may scan the collimated light across the confocal etalon or scan the etalon across the collimated light, and may comprise an acousto-optical scanner. The confocal etalon may have a free spectral range approximately equal to the E95 width of the beam being measured. The detector may comprise a photomultiplier detecting an intensity pattern of the output of the confocal etalon.

A detector module for a CT imaging system includes a scintillator to convert x-rays to optical photons. The scintillator is optically coupled to a solid-state photomultiplier with internal gain to receive the optical photons and convert them into a corresponding electrical signal output.

Blood cells of interest are readily distinguishable from other blood cells and look-a-like particles found in a blood sample by their back-scatter signature. A preferred method for differentiating platelets in a blood sample is to irradiate the cells and particles, one at a time, with a beam of radiation, and to detect back-scattered (reflected) radiation using a plurality of optical fibers to transmit the back-scattered radiation to a high-gain photodetector, e.g. a photomultiplier tube. Preferably, the back-scatter signal so obtained is combined with a second signal representing, for example, either the level of forward-scatter within a prescribed, relatively narrow angular range, or the level of side-scattered radiation, or the level of attenuation of the cell-irradiating beam caused by the presence of the irradiated cell or particle in the beam, or the electrical impedance of the irradiated cell or particle, to differentiate the cells of interest. The method and apparatus of the invention are particularly useful in differentiating platelets and basophils in a blood sample.

A catheter with a fluorescent temperature sensor is shown and described. The catheter includes a lumen, a fiber-optic cable that extends through the lumen. A distal end of the fiber-optic cable is coated with a fluorescent material and a proximal end of the fiber-optic cable is connected to a console. The console includes a light source for transmitting light through the fiber-optic cable for exciting the fluorescent material. The console further includes a photo multiplier tube for converting light emitted by the excited fluorescent material to a plurality of analog voltage signals. The console further includes a digital oscilloscope linked to the photo multiplier tube for converting the plurality of analog voltage signals to at least one digital signal. The console further includes a processor linked to the digital oscilloscope for converting the at least one digital signal to a temperature value for the distal end of the fiber-optic cable.

In a preferred embodiment, a stabilized scintillation detector, including: an LED that periodically produces a light pulse; a beam splitter that impinges some of the light pulse on a photodetector and on a photomultiplier; a scintillator that receives radiation and is coupled to the photomultiplier; and a control unit that receives signals from the photodetector and the photomultiplier representative of the light pulse received by the photodetector and the photomultiplier and receives a signal representative of temperature of the scintillator and outputs, in part, a signal to the photomultiplier to stabilize the photomultiplier. A method of using the scintillator is also provided.

Following exposure to an external light source, determining: 1) the fertility of an avian egg by measuring the photon intensity (photons per second) of the egg's biophoton and luminescence; and 2) the gender of an avian egg by measuring the photon spectrum of the egg's biophoton emission and luminescence. The external light source is either an incandescent, fluorescent, LED, (pulsed or continuous wave) monochromatic or dichromatic laser light source. The detector of the photon intensity is either a low light sensing photomultiplier tube (PMT), silicon based photon counting sensor, or Geiger-mode avalanche photodiode detector. The detector of the photon spectrum is a spectrometer. Following exposure to the referenced light sources, fertile avian eggs will exhibit a higher intensity of photons than that of unfertilized avian eggs, and avian eggs of the female gender will emit a different spectrum of photons than will avian eggs of the male gender.

Apparatus and methods for fluorescence imaging using radiofrequency multiplexed excitation. One apparatus splits an excitation laser beam into two arms of a Mach-Zehnder interferometer. The light in the first beam is frequency shifted by an acousto-optic deflector, which is driven by a phase-engineered radiofrequency comb designed to minimize peak-to-average power ratio. This RF comb generates multiple deflected optical beams possessing a range of output angles and frequency shifts. The second beam is shifted in frequency using an acousto-optic frequency shifter. After combining at a second beam splitter, the two beams are focused to a line on the sample using a conventional laser scanning microscope lens system. The acousto-optic deflectors frequency-encode the simultaneous excitation of an entire row of pixels, which enables detection and de-multiplexing of fluorescence images using a single photomultiplier tube and digital phase-coherent signal recovery techniques.

The invention relates to an optical spectrometer and a calibration method thereof. The optical spectrometer comprises a monochromator used for dividing the measured light into monochromatic lights, a photomultiplier used for receiving the monochromatic lights; the monochromator and the photomultiplier are optically connected. The photomultiplier is electrically connected with a microcontroller by a signal processing circuit. The optical spectrometer is characterized by further comprising a reference light source used for creating reference light; the reference light source which is alight-emitting diode is connected with the micro-controller. Compared with the prior art, the optical spectrometer and the calibration method thereof have the advantages as follows: 1. reasonable design, simple structure and large measuring dynamic range are ensured; 2. the absolute sensitivity of the photomultiplier is reasonably calibrated, therefore, the response linearity of the optical spectrometer is good; 3. thermostatic control is carried out to a reference detector, the reference light source and the photomultiplier, thus effectively enhancing the work stability of the optical spectrometer; and 4. the performance of the optical spectrometer is substantially enhanced under the condition that a small amount of cost is increased.

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. 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.

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.

A charged particle detector consists of a plurality independent light guide modules assembled together to form a segmented in-lens on-axis annular detector, with a center hole for allowing the primary charged particle beam to pass through. One side of the assembly facing the specimen is coated with or bonded to scintillator material as the charged particle detection surface. Each light guide module is coupled to a photomultiplier tube to allow light signals transmitted through each light guide module to be amplified and processed separately. A charged particle detector is made from a single block of light guide material processed to have a cone shaped circular cutout from one face, terminating on the opposite face to an opening to allow the primary charged particle beam to pass through. The opposite face is coated with or bonded to scintillator material as the charged particle detection surface. The outer region of the light guide block is shaped into four separate light guide output channels and each light guide output channel is coupled to a photomultiplier tube to allow light signal output from each channel to be amplified and processed separately.

An apparatus and method for characterizing cavitation that occurs in a fluid exposed to acoustic energy. The apparatus comprises a vessel for holding the fluid; an acoustic energy generating means for generating acoustic energy, the acoustic energy generating means being positioned to transmit the acoustic energy into the fluid while the fluid is held in the vessel; and a cavitation detection means for detecting cavitation in the fluid held in the vessel. In a preferred embodiment, the cavitation detection means comprises a light detection means, such as a photomultiplier tube, that detects sonoluminescent emission from the fluid. The method comprises the steps of exposing a volume of process fluid to acoustic energy at a specified power level; measuring the photon output from the fluid over a period of time; and when the photon output deviates from a desired level, initiating a remedial step to bring the photon output back to approximately the desired level.

The invention discloses an optical detection device for corona discharge. An atmospheric ultraviolet window band imaging detection optical path thereof comprises a stray light shield, an atmospheric ultraviolet window band ultraviolet lens, an atmospheric ultraviolet window band band-pass ultraviolet filter, an ultraviolet image intensifier, a light cone, a CCD or CMOS area array image sensor, an image processing circuit and a first liquid crystal display which are arranged in sequence. A solar blind ultraviolet band non-imaging detection optical path thereof comprises a total emission mirror, a spectroscope, a solar blind ultraviolet band-pass filter, a solar blind ultraviolet lens, a multiplier phototube, a signal processing circuit module and a second liquid crystal display. The device has the main advantages that the corona detection data is more complete and reliable, and the failure level of corona discharge and discharge degree are convenient to be analyzed.

This invention is a detecting of Roman-Mie dispersion laser atmosphere signal and laser radar. It sets up the radar with the output of double-frequency 532nm and triple-frequency 355nm, launches the 532nm, 15% of the 35nm to the sky and 85% of the 355nm after diffusion, and the two optical paths parallel with the optical path of the receiving telescope, and simultaneously carry out the pitching motion with the receiving telescope; the receiving telescope backward dispersing light, the backward light gets into the telescope, then passes the glare tube, the adjusting field view stop and ocular glass, and the dichroic mirror process, and divides the 407nm, the 386nm and the 532nm scattered light into three beams, and the 532nm scattered light is divided into 15% and 85% beams, and the four beams are respectively received by the multiplier phototube, magnified by the magnifier and collect and process the data. It can detect the level visibility of the atmosphere, the aerosol of the whole troposphere and the vertical outline of winding cloud light eliminating system and the water and air mixture ratio from the ground to the lower part of the troposphere. The detecting error of the level visibility is 15%, the errors of the aerosol light eliminating modulus and the vertical outline of the water and air mixture are 20%.

The invention discloses a single-wavelength four-Raman laser radar detection system and a detection method. The system combines three laser radar technologies of atmospheric temperature measurement via pure-rotation Raman scattering, vapor measurement via vibration Raman scattering, and measurement of atmosphere aerosol optical characteristics via Raman Mie scattering and an inversion method. The laser radar system employs 355 nm single-wavelength pulse laser as a detection light source and a large-diameter optical reception telescope with high transmittance for measuring the wavelength to collect atmospheric back scattering light signals, four wavelength atmospheric Raman scattering light signals and Mie scattering echo light signals of 353 nm, 354 nm, 355 nm, 386 nm, and 407 nm are mutually separated via an angle separation method of color separation filters and interference filters by a following optical path, the above five-wavelength scattering light signals are gated via narrowband interference filters, photoelectric conversion of photomultipliers of the same type is accomplished, and data acquisition is accomplished by a five-channel data collector.