Other

US Government as Represented by the Secretary of the Army

General Research Corporation

Thomas G Miller

Billie O Rogers

Thomas G Roberts

George R Edlin

Leon H Riley

Charles L Johnson

Dennis R Womack

Robert G Polk

Bonnie G McDaniel

Lee A Hilbert

John E Hagefstration

Wilford W Gebhart

Apparatus and method for discriminating against neutrons coming from directions other than a preferred direction and discriminating against gamma rays. Two photomultiplier (PM) tubes 9,10 are parallel to each other and are attached to one end of a light pipe 12. A neutron scintillator 13 is attached to the other end of the light pipe. The scintillator 13 is comprised of optical fibers arranged contiguously along a first direction, which is perpendicular to a length dimension of the optical fibers, and which optical fibers alternate between optical fibers which emit photons only in the lower portion of the electromagnetic spectrum and optical fibers which emit photons only in the higher portion of the electromagnetic spectrum. Typically, the optical fibers are about 100-250 microns. Filters 7,8 are between the PM tubes and the light pipe. One filter 7 transmits only photons in the lower end of the electromagnetic spectrum and the other filter 8 transmits only photons in the higher portion of the electromagnetic spectrum. Neutrons proceeding from a source which is parallel to the first direction will tend to cause only one optical fiber to emit photons. If neutrons enter the scintillator perpendicular to such first direction, photons will most likely be emitted by more than one optical fiber. A signal processing unit 11 will register a detected neutron if a signal is received from only one PM tube and will register a background event if signals are received from both PM tubes. If a gamma ray enters the detector and is detected, the scattered Compton electron most likely will cross two or more optical fibers, causing signals in both PM tubes. A signal processing unit 11 will register the event as a background event.

Method and apparatus for a directional neutron detector which

A contraband detection system (18) using a single, cone shaped neutron beam determines substances concealed in a sample object by developing total neutron cross section spectra for a plurality of elements, including carbon, nitrogen, oxygen, hydrogen and other potential contraband-indicating elements. A processor (26) performs a contraband determination classification based on the neutron total cross section spectra for the plurality of elements, including hydrogen and elements which do not have peaks in the energy range of interest. The contraband detection system (18) includes a neutron source (20) for producing a pulsed, cone shaped beam of fast white neutrons; a spatial neutron detection array (40); a conveyor system (28) for situating a sample object (29) between the source (20) and the detection array (40); a spectra analysis system (24) for determining the neutron total cross section spectra of elements located in the sample object; and the processor (26). The neutron source (20) produces a pulsed beam (36) of fast white neutrons having sufficient energy range whereby removal of neutrons from the beam caused by the presence of a plurality of contraband-indicating elements can be determined. Various techniques of making contraband classification determinations are also disclosed.

Contraband detection apparatus and method

An improved fast neutron x-y detector and radiographic/tomographic device utilizing a white neutron probe (4). The invention includes a multiple scattering filter (44), radiographic and tomographic imaging of the number densities of atoms in small volume increments through a sample 32 and the atomic, chemical and physical structure of a sample, (32), and neural net analysis techniques, where the neural net is trained through use of simulated volume increments. The invention detects fast neutrons over a two dimensional plane, measures the energy of the neutrons, and discriminates against gamma rays. In a preferred embodiment, the detector face is constructed by stacking separate bundles (6) of scintillating fiber optic strands (20) one on top of the other. The first x-y coordinate is determined by which bundle (6) the neutron strikes. The other x-y coordinate is calculated by measuring the difference in time of flight for the scintillation photon to travel to the opposite ends of the fiber optic strand 20. In another embodiment, the detector is constructed of discrete scintillator sections (48) connected to fiber optic strands (52) by couplers (50) functioning as lens. The fiber optic strands (52) are connected to a multi-anode photomultiplier (100) tube (56). The x-y coordinate of a neutron interaction is determined by the row and column of the affected scintillation section (48). Neutron energy for both detectors is calculated by measuring the flight time of a neutron from a point source (2) to the detector face.

High energy x-y neutron detector and radiographic/tomographic device

A laser pulse fiber optic neutron detector which is capable of discriminating against background neutrons and gamma rays while measuring both the energy of an incoming neutron and its direction has a sensor having a plurality of vertically-stacked organic fiber light pipes and a reflector at one end of the light pipes. Ionized tracks in the light pipes caused by neutron radiation are detected by directing pulsed laser radiation into one end of the light pipes and detecting the laser radiation backscattered and reflected from the light pipes.

Laser pulsed fiber optic neutron detector

Apparatus and method for detecting a particular type of particle in an energy range of interest are provided. The apparatus includes two photomultipliers (24, 26) which are spaced apart in facing relation to one another. A scintillator (22) is positioned between the photomultipliers (24, 26). The scintillator (22) comprises an array of optical fibers, preferably light pipes (40), arranged substantially contiguously side-by-side. Each of the light pipes (40) has a first end proximate the first photomultiplier (24) and an opposing second end proximate the second photomultiplier (26). Each light pipe (40) has one of its ends being non-transmissive of light. The light pipes are arranged so that contiguous ones of the light pipes (40) do not have their same ends being non-transmissive of light. Each of the light pipes (40) in the array have a cross sectional dimension thereof chosen in relation to a distance that the particular type of particle in the energy range of interest can travel. A signal processor unit (28) uses signals from the photomultipliers (24, 26) to determine when a particular type of particle in the energy range of interest is detected. The signal processor unit (28) discriminates between different types of particles and rays by determining the number of light pipes (40) affected within a predetermined time interval by an incoming particle or ray.

Method and apparatus for detecting and discriminating between particles

A device for seeing through battlefield smokes or aerosols that utilizes a igh power pulsed laser to burn or punch a hole through the smoke or aerosol and then utilize a thermal imaging device for viewing through the hole to determine objects being camouflaged by said smoke or aerosol screen.

Device for seeing through battlefield smokes and aerosols

A device for producing high power coherent radiation by using nuclear energy as the energy source to cause photons to be produced from a photon producing gas and in turn utilizing the photons to pump a laser gas to create a population inversion necessary for lasing.

High power nuclear photon pumped laser

Apparatus for accurately measuring the power of a pulsed laser without blocking or unduly perturbing the beam. The power of the beam is accurately and reliably measured by measuring the pressure of air which is expanded by heat from the laser beam.

Power measuring device for pulsed lasers

A device that can be used with high repetitions, high power, pulsed laser ams for beam diagnostics is described. The device utilizes a plurality of hole gratings made from wires or beam attenuators which are positioned in the laser beam by a synchronization technique for firing the high power pulsed laser. Each grating is in the high power beam for one pulse and is then out of the beam for (n-1) pulses, when n is the number of gratings used, to allow for cooling before it is used again.

Multi-grating attenuator for high power pulsed laser beams

A directional and size limiting gate for controlling the flow of animals between adjacent pens. Vertically disposed frame members are spaced apart in the form of an equilateral triangle. Latch and hinge arrangements along each vertical door edge permits a door to open from, or pivot from, any one of the frame members. The door has tabs horizontally extending beyond the vertical edges of the door. Each side of the door has a control rod guided by apertures in the tabs, with the control arm having hinge pins thereon. The hinge pins secure the tabs of the door to hinge sockets at spaced locations along the vertically disposed frame members. Some horizontally disposed frame members have sockets for receiving bars, said sockets being variably positionable along the horizontal frame members for controlling the size of animal passing therebetween and/or for holding one edge of the door in a selected position.

Directional and limiting gate

An animal size sorting and control gate for efficient operation in a number of operative modes permitting passage in a single direction, passage in both directions or passage in either direction. A pair of width limiters, each having a pair of horizontally disposed arms and a vertical rail extending between the arms, are pivotable with respect to horizontally disposed frame members. A plate underlying an upper horizontal frame member has a plurality of apertures arranged in circular arcs about either side of the frame members for alignment with an aperture in one of the arms of the width limiter to selectively fix the operating position of the width limiters by placing a pin through the aligned apertures. A space between the vertical rails of the width limiters determines the maximum size of animals which may pass therethrough. A pair of doors are hingedly connected to a pair of vertical frame members such that the doors span most of the area in the vertical direction between the arms of the width limiters, and in the horizontal direction between the vertical frame members and the vertical rail of the width limiters when the width limiters are pivoted into a generally co-planar relationship with the doors. Door stops along horizontal edges of the doors are positioned to cooperate against stop means on the arms of the width limiters.

Growing community of inventors

Madison, AL, United States of America

Thomas G Miller