Abstract: An electromagnetic radiation source is disclosed that produces a single mode operation at a desired operating frequency. The electromagnetic radiation source is included in a wide variety of applications including a wireless power transmission system, a system for providing wireless/high-bandwidth communications in accordance with the present invention, a lighting system, an irradiation system, a weapons system, etc.

Abstract: A device and method which comprises a sensing surface on a membrane, solid surface or electrode, where the sensing surface contains a photo-voltage active material chosen in relation to a particular target substance to be detected and quantified. The photo-voltage active material is of a type which produces an interfacial photo-voltage electrical signal upon illumination. The particular photo-voltage active material chosen for a particular target substance is one in which the presence of the target substance causes a change in the electrical signal produced. The presence of the target substance modifies the expected photo-voltage produced by the sensing surface upon illumination. The photo-voltage produces signals which are detected by electronic circuits, and the presence and concentration of the target substance is determined by analyzing the difference between the photo-voltage of the target sample versus the photo-voltage of a control sample lacking the target substance.

Abstract: The system and method provide security and cargo handling personnel a versatile tool to rapidly check cargo for hidden radiological materials, explosives, drugs, and chemical weapons material. Gamma ray emission is stimulated by a pulsed neutron source. The gamma ray signature is used to classify the material. Passive gamma ray analysis can be used to detect and identify radiological material. The method of determining the contents of a target includes irradiating a target; detecting at least one spectrum emitted from the target; performing a primary analysis to extract a first set of indicators; and performing a secondary analysis to decide the contents of the target. The primary analysis utilizes either a least squares analysis or principal component analysis. The secondary analysis utilizes a generalized likelihood ratio test or support vector machines.

Abstract: Discriminating radioactive nuclides of a gamma ray source and nondestructively measuring an image concentration and spatial distribution of a gamma ray by radioactive nuclides. A visualizing apparatus having a container 1 including a gamma ray source 2; a gamma ray detector 7 around the container 1 which detects gamma rays through a collimator 6; a gamma ray detection signal processing device 9 which processes a gamma ray detection signal measuring energy and counted value thereof; an energy discrimination processing device 10 which performs discrimination and intensity analysis of radioactive nuclides by performing spectrum analysis of gamma ray energy and intensity measured for each unit time or position; an imaging calculation processing device 11 which forms images of concentration and space distribution of the gamma ray source for each discriminated radioactive nuclide; and an image display device 12 which performs visual display based on a result of the calculation processing.

Abstract: An approach for the selection of Compton camera shapes, configurations, positions, orientations, trajectory paths, and detector element sets is provided for collecting data for analysis using the surface integral and integral-of-line-integral methods of reconstruction Compton data. Methods are introduced for (1) selecting one or more imaging lines through a radioactive distribution for which approximations of integrals of radioactivity are to be derived, (2) selecting and using Compton camera relative positions, relative orientations, and detector element sets that “correspond to” the selected imaging lines to collect the needed data; and (3) deriving approximations of integrals of radioactivity along those imaging lines. This methodological approach is used to reconstruct line integrals, cross-sections, local volumes, parallel projections, and cone-beam projections of radioactive distributions.

Abstract: A measurement device, such as a laser radar, is described that comprises a transmitter portion for transmitting radiation to a remote probe volume, a receiver portion for detecting radiation returned from the remote probe volume and a processor for analysing the detected return radiation. The device is suitable for transmitting and receiving radiation through a window portion having associated window cleaning apparatus (e.g. wiper 62) for cleaning said window portion in response to a cleaning activation signal. The processor is arranged to generate a cleaning activation signal for activating window cleaning apparatus when the properties of said detected return radiation are indicative of a reduction in transmission through at least part of said window portion. In one embodiment, a conically scanned lidar is described that generates a cleaning activation signal when the power of detected return radiation varies as a function of the angle of transmission of radiation from the device.

Abstract: In a vehicle, a single detector plane simultaneously measures radiation coming through two coded-aperture masks, one on either side of the detector. To determine which side of the vehicle a source is, the two shadow masks are inverses of each other, i.e., one is a mask and the other is the anti-mask. All of the data that is collected is processed through two versions of an image reconstruction algorithm. One treats the data as if it were obtained through the mask, the other as though the data is obtained through the anti-mask.

Abstract: The present invention relates to a device enabling quantification of dose delivery in radiotherapy treatment during patient-specific treatment of the patient utilising measurements in predefined time-intervals with information means positioned in the radiation beam, between the patient and the source and converting the readings to corresponding measures in a phantom.

Abstract: The method shows how to violate predictions of quantum mechanics for matter. For light, the method has been disclosed in patent application Photon Violation Spectroscopy. The methods are different in specifying different methods for light and matter. For matter, the method typically uses the single 5.5 MeV alpha (He++) emitted from the radioisotope Americium-241 in spontaneous decay, a thin gold foil beam splitter, and two surface barrier alpha detectors. The detectors deliver a characteristic electrical pulse with amplitude proportional to matter wave energy. A circuit reads the coincidence rate and singles rates of pulses from the two detectors. Quantum mechanics predicts that the particle would go one way or the other at the beam splitter, and coincident detections of pulses characteristic of such a particle would occur only at an easily calculated chance rate. However, the method at hand shows such characteristic pulses occur in coincidence at a rate greatly exceeding chance.

Abstract: Methods and apparatus for analyzing gas-oil-water compounds in oilfield and other applications are disclosed using terahertz radiation. A sample analyzer includes a sample chamber having a fluid communication port configured to receive the sample. The analyzer also includes a filter to filter samples and selectively remove oil, water or gas from reservoir mixture received by the sample chamber. A terahertz (THz) radiation detector is provided in electromagnetic communication with the sample. The terahertz detector provides a detected output signal indicative of the terahertz electromagnetic radiation detected from the sample. In some embodiments, the device also includes a terahertz source illuminating the sample, the terahertz detector detecting a portion of the terahertz source illumination as modified by the sample. The detected portion of the spectrum of terahertz radiation can be processed to analyze the composition of the sample.

Abstract: A radiological imaging apparatus of the present invention includes an X-ray source for emitting an X-ray, a ?-ray detecting section for outputting a detection signal of a ?-ray, and an X-ray detecting section for outputting a detecting signal of an X-ray. The X-ray source moves around a bed for placing an examinee. The ?-ray detecting section has a plurality of radiation detectors aligned in the longitudinal direction of the bed and placed around the bed. The X-ray detecting section is positioned in a region formed between one end and the other end of the ?-ray detecting section in the longitudinal direction of the bed. The X-ray source is also positioned in the region. Since the X-ray detecting section is placed in the region, it is possible to accurately combine a PET image and an X-ray computed tomographic image.

Abstract: A method and apparatus for discriminating the types of radiation interacting with an integrated radiation detector having of a pulse-mode operating photosensor which is optically coupled to a gamma-ray scintillator sensor and a neutron scintillator sensor and uses an analog to digital converter (ADC) and a charge to digital converter (QDC) to determine scintillation decay times and classify radiation interactions by radiation type. The pulse processing provides for, among other things, faithful representation of the true energy spectrum of the gamma radiation field and allows for radioisotope identification by searching for the presence of characteristic energy lines in the gamma energy spectrum. The pulse shape discrimination method ensures that the high sensitivity and resolution of the isotope identification function is not affected during operation in mixed neutron-gamma fields.

Abstract: To detect whether a substrate is in a focal plane of a scatterometer, a cross-sectional area of radiation above a certain intensity value is detected both in front of and behind a back focal plane of the optical system of the scatterometer. The detection positions in front of and behind the back focal plane should desirably be equidistant from the back focal plane along the path of the radiation redirected from the substrate so that a simple comparison may determine whether the substrate is in the focal plane of the scatterometer.

Abstract: The present invention relates to a beam analyzing system and a method for analyzing pulsed particle or laser beams. The inventive beam analyzing system comprises a detector unit, a unit for generating a pulsed reference laser beam, a first electro-optical modulator and a first read-out photo detector, wherein the optical input of the first electro-optical modulator is connected with the unit for generating a pulsed reference laser beam, wherein the optical output of the first electro-optical modulator is connected with the first readout photo detector and wherein the signal input of the first electro-optical modulator is connected with the detector unit.

Abstract: Laser scanning apparatus and method using diffractive optical elements are disclosed. In one embodiment, an apparatus includes a radiation source to generate a radiation beam with an intensity profile and a wavelength capable of heating a region of a substrate, a beam shaping device based on a diffractive optical element (DOE) to transform the radiation beam to a particular shape with a particular intensity profile to illuminate the region and a state adapted to support the substrate. In another aspect, a method includes generating from a radiation source a radiation beam with an intensity profile and a wavelength capable of heating a region of a substrate transforming a shape of the radiation beam with the intensity profile to a particular shape of the radiation beam with a particular intensity profile through processing the radiation beam in a beam shaping device based on a diffractive optical element (DOE).

Abstract: Apparatus and accompanying methods for the detection and subsequent destruction or disablement of Improvised Explosive Devices (IEDs) while maintaining a satisfactory level of human safety. Operationally, our inventive method and apparatus detects the IED using one or more methods including: detecting internal battery components; detecting magnetic signature(s) of the IED; detecting a characteristic energy spectrum of the IED; and/or detecting characteristic chemical signatures of the device(s). Once detected, the device may be further characterized and then subsequently deactivated and/or destroyed by a shaped pulse charge directed at the device or its power source (battery) from a safe distance.

Abstract: A method for producing stimulated emission of gamma radiation comprising: 1] providing at least first and second gamma-radiation sources, both sources being in recoil-free first-excited nuclear levels and the second source being in resonance with the first source and the gamma radiation from the first source being incident on the second source, 2] during the lifetime of its excited state, abruptly moving the first source through a distance equal to ½ the wavelength of the radiation emitted therefrom, thereby inducing a ?-phase-shift gamma radiation transparency in the second source whereby the ?-phase-shifted gamma radiation stimulates the excited nuclear resonant state of the second source to emit gamma radiation.

Abstract: The invention provides a method for the identification of deposits of solid materials in process plants, the method comprising the creation of a theee-dimensional image by means of tomography, preferably passive tomography, most preferably gamma-ray tomography. Typically, the solid materials comprise gamma-ray emitting solid materials and the process plants comprise nuclear process plants. In general, the deposits of solid materials are deposited from liquid media, and the liquid media preferably comprise aqueous suspensions of these materials. The method is particularly applicable to highly active nuclear waste liquids in High Activity Storage Tank (HAST) applications, and offers significant advantages over the methods of the prior art, since it comprises a non-invasive technique which does not require the prior installation of a detector in the vessel from which data are to be obtained.

Abstract: A radiation detector includes: a radiation detecting unit including a radiation sensor detecting a radiation sensitive to light, a signal amplifier, a pulse-height discriminator, and a counter; an optical pulse emitting unit configured to emit an optical pulse for confirming operational integrity of the radiation detecting unit; an emission controlling unit configured to control an operation of the optical pulse emitting unit; and a light path through which light is led from the optical pulse emitting unit to a vicinity of the radiation sensor. The emission controlling unit including a mechanism for adjusting emission time characteristics of the optical pulse emitting unit.

Abstract: A method for high spatial resolution imaging of a plurality of sources of x-ray and gamma-ray radiation is provided. High quality mechanically bent diffracting crystals of 0.1 mm radial width are used for focusing the radiation and directing the radiation to an array of detectors which is used for analyzing their addition to collect data as to the location of the source of radiation. A computer is used for converting the data to an image. The invention also provides for the use of a multi-component high resolution detector array and for narrow source and detector apertures.

Abstract: The present invention relates to a method of detecting and localizing gamma radiation from a target source in the possible presence of background gamma radiation, said method comprising the steps of: a) detecting the directional intensity distribution of gamma rays with respect to a preferred direction, b) analysing the direction dependence, correcting for efficiency and solid angle of the detection means, c) determining the amount and spatial distribution of background radiation, d) determining the background contribution of the intensity measured in the preferred direction from the amount and spatial distribution of background radiation, e) determining the strength of gamma radiation in a preferred direction by subtracting from the intensity measured in the preferred direction any background contribution from non preferred directions.

Abstract: Systems and methods are described for detecting the presence and/or absence of a solid, liquid or gas which utilize an RF energy emitter and RF energy detector for determining whether a solid, liquid or gas is present within a defined physical space. More specifically, an RF energy emitter is provided at a first side of a solid, liquid or gas transmission channel and an RF energy receiver/detector is provided at an opposite side of the solid liquid or gas fluid channel. The RF energy emitter either continuously or periodically emits RF energy which in the preferred exemplary embodiment is in the high-frequency or more preferably ultrahigh frequency signal range. The amount of detected RF energy transferred across the channel is used in determining the presence and/or absence of a solid, liquid or gas.

Abstract: An electromagnetic radiation source is disclosed. The electromagnetic radiation source includes an anode having a first conductor, a second conductor positioned relative to the first conductor, a plurality of pole pieces coupled to at least one of the first conductor and the second, and at least one mechanical phase reversal positioned along the first conductor or second conductor. Adjacent pole pieces are separated by a gap. The electromagnetic radiation source also includes a cathode separated from the anode by an anode-cathode space, electrical contacts for applying a dc voltage between the anode and the cathode and establishing an electric field across the anode-cathode space, and at least one magnet arranged to provide a dc magnetic field within the anode-cathode space generally normal to the electric field.

Abstract: Systems and methods are described for image reconstruction. A set of conical integrals are calculated to satisfy a completeness condition and are related to a distribution of radioactivity.

Abstract: This invention relates to an apparatus for detecting hydrogeneous material on a ship's deck comprising a neutron source located below the surface of the ship's deck and emitting fast/energy-rich neutrons, and a detector device that is located below the surface of the ship's deck and detecting thermal neutrons. The invention further relates to a corresponding method of detecting hydrogeneous material on a ship's deck. Hereby an apparatus and a method are provided for detecting occurrences of water on a ship's deck, wherein these occurrences appear in particular when travelling in rough weather conditions. The apparatus being located below the ship's deck, it is consequently not exposed to wear due to rough weather conditions.

Abstract: The present invention is directed toward an apparatus and methods for detection and identification of target radionuclides and threatening radionuclides that may be present in a sample volume. One aspect of the invention provides a digital computational apparatus that determines similarity or identity to a target radionuclide or a threatening radionuclide. In another aspect, the invention provides a high throughput apparatus for detection of a target radionuclide in a sample volume, or for identifying a target radionuclide present in a sample volume. In a further aspect the invention provides a high throughput apparatus for communicating the presence of a target radionuclide in a sample volume, the identity of a target radionuclide in a sample volume, or both to appropriate personnel.

Abstract: A method of measuring the activity of a radioisotope (3) placed in an ionisation chamber (1) consists in:—determining the energy spectrum of the radiation emitted by the radioisotope;—automatically comparing the energy spectrum with a set of pre-recorded or pre-programmed radioisotope energy spectra in such a way as to identify the radioisotope present;—subsequently, automatically directing the calibration coefficient corresponding to the radioisotope present to the electronic measuring elements in order to obtain the appropriate activity measurement. The invention provides a totally automatic activity measurement. Moreover, the invention also relates to an activity meter with radioisotope recognition which is used to obtain an automatic activity measurement. The device employs one or more scintillation—or semi-conductor-type radiation detectors (10) for determining the energy spectrum of the radioisotope present.

Abstract: A method of obtaining a tomographic image of part of an animal or a part of an animal including a human being or a part of a human being by using radioactive radiation is disclosed. The animal is at least partly placed into a measuring cavity having an axial axis. The measuring cavity being at least partially surrounded by a cavity wall which is provided with a plurality of pinholes, and behind the pin holes (as viewed from the measuring cavity or lumen) detection means are placed. A radioactive radiation from a radioactive isotope administered to the animal is detected in a position-related manner by the detection means and data obtained with the detection means are used for the generation of the tomographic image.

Abstract: A method of creating an image of a radiation source includes detecting radiation associated with a first location of the radiation source. Data substantially corresponding to the radiation associated with the first location is processed to provide a first value. The first value is employed to generate a first portion of the image associated with the first location. Radiation associated with a second location of the radiation source is detected. Data substantially corresponding to the radiation associated with second location is processed to provide a second value. The second value is employed to generate a second portion of the image associated with the second location.

Abstract: An accelerated weathering test apparatus and method for calibration and operation thereof including a spectroradiometer for monitoring a full spectrum power distribution of a light source. Calibration includes a calibration light source in a factory test apparatus operated at a fixed power level and collecting the full spectrum power distribution of the calibration light source to generate a first data set. The calibration light source is then installed in a client test apparatus and operated at the fixed power level in order to collect the full spectrum power distribution and generate a second data set. The first and second data sets are filtered and aligned to determine a system response factor of the client test apparatus so that the irradiance level control may be calibrated.

Abstract: A method and apparatus are provided for determining radiation dose rates at selected locations within an environment. Incident gamma ray energy and count rate are measured at one or more measured locations within the environment to obtain a measured spectrum for those measured locations. The spatial position of the measured locations is also measured. An emitted spectrum is then determined for the measured locations based on the measured spectrum. The emitted spectrum may then be used to determine the dose rate at one or more selected locations (which may be different than the measured locations). In this way the invention provides an accurate solution for the dose rate at any point of interest within the environment based on the measured count and incident energies.

Abstract: A method of creating an image of a radiation source includes detecting radiation associated with a first location of the radiation source. Data corresponding to the radiation associated with the first location is processed to provide a first value. The first value is employed to generate a first portion of the image associated with the first location. Radiation associated with a second location of the radiation source is detected. Data corresponding to the radiation associated with second location is processed to provide a second value. The second value is employed to generate a second portion of the image associated with the second location.

Abstract: A method of obtaining a tomographic image of part of an animal or a part of an animal including a human being or a part of a human being by using radioactive radiation is disclosed. The animal is at least partly placed into a measuring cavity having an axial axis. The measuring cavity being at least partially surrounded by a cavity wall which is provided with a plurality of pinholes, and behind the pin holes (as viewed from the measuring cavity or lumen) detection means are placed. A radioactive radiation from a radioactive isotope administered to the animal is detected in a position-related manner by the detection means and data obtained with the detection means are used for the generation of the tomographic image.

Abstract: An X-ray or neutron-optical system comprising an X-ray or neutron source (1) from which corresponding radiation is guided as a primary beam (2) to a sample (4) under investigation, with an X-ray or neutron detector (6) for receiving radiation diffracted or scattered from the sample (4), wherein the source (1), the sample and the detector are disposed substantially on one line (=z-axis) and wherein a beam stop (5; 31; 41) is provided between the sample and the detector whose cross-sectional shape is adjusted to the cross-section of the primary beam is characterized in that the beam stop is disposed to be displaceable along the z-direction for optimum adjustment of the amounts of useful and interfering radiation impinging on the detector. This protects the detector from the influence of the primary beam while allowing a maximum amount of diffracted or scattered radiation to reach the detector, wherein the beam stop can be easily adjusted to temporally changing properties of the beam optics.

Abstract: A method and system for detecting ionizing radiation emitted by material located over an extended area are provided. The method and system include a radiation detector disposed within a detector space on a detection axis. An array of collimating louvers is positioned about the radiation detector and is movable between different polar positions or angles relative to the detection axis. A mechanism is provided for moving the array of collimating louvers between the different polar angles to collimate the ionizing radiation from different locations over the area. The detector produces electrical signals as a function of the polar positions of the array of collimating louvers.

Abstract: A method of creating an image of a radiation source includes detecting radiation associated with a first location of the radiation source. Data corresponding to the radiation associated with the first location is processed to provide a first value. The first value is employed to generate a first portion of the image associated with the first location. Radiation associated with a second location of the radiation source is detected. Data corresponding to the radiation associated with second location is processed to provide a second value. The second value is employed to generate a second portion of the image associated with the second location.

Abstract: A high efficiency radiation detector employs longitudinally extending converter elements receiving longitudinally propagating radiation to produce high-energetic electrons received by detector structures in interstitial spaces. The secondary electron generation in this architecture allows great freedom in selection of converter materials and thickness. A variety of detector mechanisms may be used including ionization-type detectors or scintillation-type detector.

Abstract: A method of obtaining a tomographic image by using radioactive radiation. In accordance with the invention a method is used wherein a measuring cavity is used comprising an array of pinholes, wherein an axial component of the distance between two neighboring pinholes is smaller than the distance between two neighboring pinholes which in relation to the axial direction are situated in a transversal plane, behind a pinhold Pi detection means are placed, and that means are provided to limit the chance that via pinhole Pi radiation reaches any detection means other than detection means Di. The invention also relates to a suitable apparatus.

Abstract: The invention provides an improved correction technique for use in analysing bodies of material containing radioactive sources.

Abstract: The present invention provides an improved method for investing radioactive sources which takes into account variations in the materials potentially making up the samples. In particular, the invention provides a method of investigating radioactive sources in a sample, the method comprising detecting a portion of the emissions arising from the sample at an energy, the detected portion relating to a detected level, the detected being corrected according to a correction method to give a corrected level at that energy. The invention also provides improved transmission sources and improved transmission based correction techniques for use in investigating radioactive sources in a sample.

Abstract: A radiation detector system includes detectors having different properties (sensitivity, energy resolution) which are combined so that excellent spectral information may be obtained along with good determinations of the radiation field as a function of position.

Abstract: Servocontrol is achieved on a radiation detector that controls a motor (7) that makes a rod (9) slide, tilting a mobile portion (12) of an absorbing enclosure (2) to open or close a collimation slit (3) and adjust the amount of radiation received by the detection solid (1) to an ideal value for measurement precision. This device can be used particularly in gamma spectrometry.

Abstract: Methods for quantifying the irradiation dose received by an item or items, such as food items and medical items, undergoing irradiation-based sterilization, includes the steps of monitoring a selected electronic parameter associated with an economic single use sensor positioned adjacent the item or items and telemetrically relaying data associated with the monitored electronic parameter to a computer. The computer includes a computer program which is configured to determine the radiation dose received by the item or items by correlating the value of the monitored electronic parameter to a corresponding amount of radiation associated with the value. Related sensors and systems are also described.

Abstract: A high-flow rate, low-noise, gas sampling apparatus for collecting particulate such as biological, chemical, and radioactive material from a gas on a collector such as an impaction collector includes a housing having an inlet and an outlet and a fan disposed within the housing for drawing the gas into the inlet, past the collector for sampling, and exhausting the gas through the outlet. The fan is operable to produce a flow of gas through the housing of greater than about 50 liters per minute with a noise level emitted from the apparatus being less than about 60 decibels. The apparatus may be configured as a compact, unobtrusive, portable, lightweight apparatus for use in various indoor or outdoor locations. The apparatus may also include a sensor for the detection of radioactive material collected on the collector, a processor for monitoring the sampling, and the apparatus may be linked to a communications network such as the Internet. Methods for collecting particulate from a gas are also enclosed.

Abstract: A method and apparatus are provided for assaying a waste container. The method includes the steps of forming a plurality of slices through a volume of the waste container, performing a relatively fast passive prescan to measure a level of radioactivity of each of the plurality of slices and identifying at least some slices of the plurality of slices having a relatively high level of radioactivity. In addition, the method includes the steps for performing a relatively fast active prescan of the drum to determine the average attenuation of the plurality of slices. The method further includes the steps of determining an passive assay time for the identified slices based upon the measured radioactivity and average attenuation and performing relatively slow passive and active CT scans of the identified slices based upon the determined passive and active CT assay time to quantify a source of the measured radioactivity by weight.

Abstract: A method, system and a radiation detector system for use therein are provided for determining the depth distribution of radiation-emitting material distributed in a source medium, such as a contaminated field, without the need to take samples, such as extensive soil samples, to determine the depth distribution. The system includes a portable detector assembly with an x-ray or gamma-ray detector having a detector axis for detecting the emitted radiation. The radiation may be naturally-emitted by the material, such as gamma-ray-emitting radionuclides, or emitted when the material is struck by other radiation. The assembly also includes a hollow collimator in which the detector is positioned. The collimator causes the emitted radiation to bend toward the detector as rays parallel to the detector axis of the detector. The collimator may be a hollow cylinder positioned so that its central axis is perpendicular to the upper surface of the large area source when positioned thereon.

Abstract: An absolute time scale clock includes a radioactive isotope and a computer. The computer includes a processor that determines an indication of the current absolute time and a memory that stores a decay constant of the radioactive isotope, a reference time, and an amount of the isotope at the reference time. A energy supply that provides power to the computer. The absolute time scale clock further includes a detector positioned to respond to emissions from the radioactive isotope. The detector generates an indication of the number of emissions over a time interval that varies with the decay rate of the isotope. The processor is responsive to the indication from the detector, the decay constant, the reference time, and the reference amount to determine the indication of current absolute time.

Abstract: A method and system for detecting ionizing radiation emitted by material located over an extended area are provided. The method and system include a radiation detector disposed within a detector space on a detection axis. An array of collimating louvers is positioned about the radiation detector and is movable between different polar positions or angles relative to the detection axis. A mechanism is provided for moving the array of collimating louvers between the different polar angles to collimate the ionizing radiation from different locations over the area. The detector produces electrical signals as a function of the polar positions of the array of collimating louvers.

Abstract: A method, system and a radiation detector system for use therein are provided for determining the depth distribution of radiation-emitting material distributed in a source medium, such as a contaminated field, without the need to take samples, such as extensive soil samples, to determine the depth distribution. The system includes a portable detector assembly with an x-ray or gamma-ray detector having a detector axis for detecting the emitted radiation. The radiation may be naturally-emitted by the material, such as gamma-ray-emitting radionuclides, or emitted when the material is struck by other radiation. The assembly also includes a hollow collimator in which the detector is positioned. The collimator causes the emitted radiation to bend toward the detector as rays parallel to the detector axis of the detector. The collimator may be a hollow cylinder positioned so that its central axis is perpendicular to the upper surface of the large area source when positioned thereon.

Abstract: A non-destructive method and apparatus which is based on in-situ gamma spectroscopy is used to determine the depth of radiological contamination in media such as concrete. An algorithm, Gamma Penetration Depth Unfolding Algorithm (GPDUA), uses point kernel techniques to predict the depth of contamination based on the results of uncollided peak information from the in-situ gamma spectroscopy. The invention is better, faster, safer, and/cheaper than the current practice in decontamination and decommissioning of facilities that are slow, rough and unsafe. The invention uses a priori knowledge of the contaminant source distribution. The applicable radiological contaminants of interest are any isotopes that emit two or more gamma rays per disintegration or isotopes that emit a single gamma ray but have gamma-emitting progeny in secular equilibrium with its parent (e.g., 60Co, 235U, and 137Cs to name a few).