Abstract: Devices and methods for detecting radiation are described. A detector for detecting radiation comprises a housing containing an ionisable gas, an array of anode wires extending substantially in a first plane, and arranged to be held at a first potential for attracting electrons, and at least one cathode wire spaced in a predetermined relationship from the anode wires, arranged to be held at a second, lower potential. The detector further comprises at least one additional electrode positioned adjacent a periphery of the array of anode wires, and arranged to be held at a third potential, greater than the second potential. A window for a radiation detector is described and comprising a housing containing an ionisable gas is also described. The window comprises a layer formed of an electrically conductive material forming an electrode, a layer formed of a plastic, arranged to support the layer formed of electrically conductive material, and a layer of gas impermeable material.

Abstract: A detector for detecting ionising radiation having at least one detector arranged to be connected to a read-out arrangement for the reading-out and the evaluation of a signal from the detector. The detector has a carrier material and a layer having an active detector material applied to the carrier material, which active detector material is arranged, in the event of its receiving incident ionising radiation that is incident upon the layer, to give rise to ionisation in the active detector material in the layer. An electrical field is applied across the layer, whereby the ionisation gives rise to an electric current. The read-out arrangement is arranged to detect such that it can in this way detect the incident ionising radiation. The active detector material in the layer contains ZnO to such an extent that ionising radiation gives rise to a detectable electric current.

Abstract: Disclosed herein is a method of determining a characteristic of radiation detected by a radiation detector via a multiple-pixel event having a plurality of radiation interactions. The method includes determining a cathode-to-anode signal ratio for a selected interaction of the plurality of radiation interactions based on electron drift time data for the selected interaction, and determining the radiation characteristic for the multiple-pixel event based on both the cathode-to-anode signal ratio and the electron drift time data. In some embodiments, the method further includes determining a correction factor for the radiation characteristic based on an interaction depth of the plurality of radiation interactions, a lateral distance between the selected interaction and a further interaction of the plurality of radiation interactions, and the lateral positioning of the plurality of radiation interactions.

Abstract: A radiation detector has an electron emitter that includes a coated nanostructure on a support. The nanostructure can include a plurality of nanoneedles. A nanoneedle is a shaft tapering from a base portion toward a tip portion. The tip portion has a diameter between about 1 nm to about 50 nm and the base portion has a diameter between about 20 nm to about 300 nm. Each shaft has a length between about 100 nm to about 3,000 nm and an aspect ratio larger than 10. A coating covers at least the tip portions of the shafts. The coating exhibits negative electron affinity and is capable of emitting secondary electrons upon being irradiated by radiation. The nanostructure can also include carbon nanotubes (CNTs) coated with a material selected from the group of aluminum nitride (AlN), gallium nitride (GaN), and zinc oxide (ZnO).

Abstract: The instant invention relates a convertible radiation beam analyzer for measuring the distribution and intensity of radiation produced by a radiation source. More specifically, the instant invention is a convertible radiation scanning device that includes a single guideway module constructed and arranged for attachment to dynamic phantom tank in various orientations for traversing a radiation detection probe through a radiation beam along various axes to determine radiation intensity and distribution throughout the beam.

Abstract: An energy cell, employed as a passive energy source or a detector for sensing high energy photons, takes advantage of the differing electrical properties of metals to produce an induced electromagnetic force charge when exposed to dosages of high energy photons such as x-ray or gamma rays.

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 miniaturized and highly integrated optical deflection apparatus is realized in which the number of electrodes for driving the optical deflection apparatus is reduced. The optical deflection apparatus implements a sheet member that is electrically floating and plural electrodes that are implemented on a substrate. The sheet member includes a member having a light reflection region and an electret member that is charged at a predetermined electric potential. The sheet member is tilted by applying an electric potential that is substantially equivalent to an electric potential of the electret member to one of the electrodes and applying a ground potential to another one of the electrodes.

Abstract: One embodiment of the present invention is an electron beam treatment apparatus that includes: (a) an array of lamps that output radiation; (b) a support mechanism adapted to support a substrate at a treatment position above the lamps; and (c) a lamp heat shield, disposed above the array, having a radiation absorption portion adapted to absorb radiation from at least a portion of the array, and a radiation reflection portion adapted to reflect radiation from at least a portion of the array towards the substrate when disposed at the treatment position.

Abstract: A method and apparatus for determining the position of a gamma ray interaction are disclosed. A medium that emits light in response to an interaction between a gamma ray and the medium is provided. A plurality of photodetectors is used to detect the light and determine a first three-dimensional position of the interaction. A field is produced in the medium that directs ionization electrons resulting from the interaction to a collector. A portion of a shutter system that corresponds to the interaction is opened. The shutter selectively blocks and permits the passage of the ionization electrons to the collector. A second three-dimensional position of the interaction is determined by localizing a two-dimensional position of the interaction in the collector and determining a third dimension based on a time of arrival of the ionization electrons relative to when the light is detected.

Abstract: The invention relates to a multi-layered radiation converter, a radiation detector comprising such a converter as well as a radiation-based imaging system using such a detector. Each converter layer (32) in the radiation converter is adapted for interaction with incident radiation to cause the emission of electrons into drift holes defined in the converter layer. The drift holes of one converter layer (32-1) are staggered with respect to the drift holes of another converter layer (32-2). By mutually shifting the converter layers such that the drift holes of two different layers are no longer well-aligned, but rather staggered with respect to each other, the effective conversion area will be increased, and the probability of incoming radiation passing through the stack without interaction with the converter layers will be significantly reduced.

Abstract: A radiation detector including a chamber capable of being filled with an ionizable and scintillating substance, and a radiation entrance arranged such that radiation can enter said chamber partly for ionizing said ionizable and scintillating substance, partly for being converted into light therein, is disclosed. The detector further includes a light detector for detection of said light, and an electron avalanche detector for avalanche amplification and detection of electrons released as a result of the ionization. Further, there are provided means for correlating detected light and detected electrons, which are derivable from a single radiation photon; and means for producing a signal from the correlated detected light and detected electrons. The detector is particularly suitable for positron emission tomography (PET).

Abstract: A high-speed, three-dimensional, gamma-ray imaging method and system as well as a detector and array of such detectors for use therein are provided which characterize radioactivity distributions in nuclear and radioactive waste and materials facilities by superimposing radiation images on a view of the environment using see-through display screens or shields to provide a stereoscopic view of the radiation. The method and system provide real-time visual feedback about the locations and relative strengths of radioactive sources. The method and system dynamically provide continuous updates to the displayed image illustrating changes, such as source movement. A pair of spaced gamma-ray cameras of a detector subsystem function like “gamma eyes”. A pair of CCD cameras may be coupled to the detector subsystem to obtain information about the physical architecture of the environment.

Abstract: A method and apparatus for determining the position of a gamma ray interaction are disclosed. A medium that emits light in response to an interaction between a gamma ray and the medium is provided. A plurality of photodetectors is used to detect the light and determine a first three-dimensional position of the interaction. A field is produced in the medium that dire ionization electrons resulting from the interaction to a collector. A portion of a shutter system that corresponds to the interaction is opened. The shutter selectively blocks and permits the passage of the ionization electrons to the collector. A second three-dimensional position of the interaction is determined by localizing a two-dimensional position of the interaction in the collector and determining a third dimension based on a time of arrival of the ionization electrons relative to when the light is detected.

Abstract: A thin film ferroelectric/piezoelectric discharge device exhibits a stable high electrical resistance state. With an applied voltage, electron avalanche breakdown occurs and the device exhibits a low resistance state and recovers from this state. Thereby it is a solid state spark gap. With reduction of the voltage after breakdown the conduction of current ensues and contributes to the spontaneous recovery of the high resistive state evidenced by the measured increase in resistance in time. Gamma radiation ionization perturbs this recovery rate and this can be measured and differentiated from the conduction current induced resistance change. Thereby it is a room temperature gamma detector. The device is made by growing a controlled thickness of oxide on a titanium metal or alloy (12) surface (14) by anodization; heating in a metal oxide powder transforming the oxide into a ferroelectric/piezoelectric (16); and applying an electrode (18) to the exposed ferroelectric/piezoelectric surface.

Abstract: A radiation detector that utilizes an unregulated power supply as opposed to a regulated power supply, since quantitative results are not required, only an audible signal, and an unregulated power supply is less expensive than that of a regulated power supply. The radiation detector includes a Geiger-muller tube, a nine volt DC power supply, a solid state oscillator with an output of 2 kilohertz, a high voltage power supply, and an audio amplifier.

Abstract: Ionising radiation detector with solid radiation conversion strip and manufacturing process for this detector.

Abstract: A photo-ionization detector (PID) including two detection units controls gas flows through the ionization chambers of the detection units for real-time self-cleaning and measurement. Operation of the PID can include flowing gas through the ionization chamber of one detection unit to measure the volatile gas concentration while stopping gas flow through the ionization chamber of the other detection unit. A UV lamp converts oxygen contained in the closed ionization chamber to ozone, which removes contamination in the closed ionization chamber, Continuous gas flows can alternate between one ionization chamber to the other. Alternatively, a PID with only one gas detection unit intermittently interrupts the flow of the ambient gas in the ionization chamber.

Abstract: The invention relates to a multi-layered radiation converter, a radiation detector comprising such a converter as well as a radiation-based imaging system using such a detector. Each converter layer (32) in the radiation converter is adapted for interaction with incident radiation to cause the emission of electrons into drift holes defined in the converter layer. The drift holes of one converter layer (32-1) are staggered with respect to the drift holes of another converter layer (32-2). By mutually shifting the converter layers such that the drift holes of two different layers are no longer well-aligned, but rather staggered with respect to each other, the effective conversion area will be increased, and the probability of incoming radiation passing through the stack without interaction with the converter layers will be significantly reduced.

Abstract: Bradbury-Nielson gates for the modulation of beams of charged particles, particularly ion beams in mass spectrometry, have been produced with an adjustable wire spacing down to 0.075 mm or a smaller spacing. The gates are robust, they can be fabricated in less than 3 hours, and the method of production is reproducible. In time-of-flight mass spectrometers, fine wire spacing leads to improvements in mass resolution and modulation rates. Gates that were produced using this new method have been installed in a Hadamard transform time-of-flight mass spectrometer in order to demonstrate their utility.

Abstract: The invention concerns a device and method for two-dimensional imaging and timing of particles or electromagnetic radiation with improved pulse-pair resolution. A detector, e.g. a michrochannel plate detector with a delay-line anode with three or more conductive members is used as exemplary embodiment for achieving these requirements. Redundant position and timing information is used for uniquely determine the timing and position of two or more particles, even if they arrive at the same time at the detector.

Abstract: A vapor trap for detecting VOCs includes a housing, having a first end portion, a second end portion and at least one opening for receiving gas vapor. The housing is at least partially buried in ground with a vapor containment mechanism detachably connected to the first end portion of the housing. The vapor containment mechanism can be removed after a predetermined time period and replaced with a vapor sampling mechanism. An organic vapor analyzer can be connected in fluid relationship to the vapor sampling mechanism to measure VOCs. Optionally, a vacuum pump can be utilized to draw vapor into the vapor trap and then subsequently into the organic vapor analyzer. There can be a first selector valve located between the vapor sampling mechanism and the vacuum pump and a second selector valve located between the vapor sampling mechanism and the organic vapor analyzer. A preferred organic vapor analyzer is a photo-ionization detector.

Abstract: In a flame ionization sensor type gas combustion control apparatus, the sensor is provided with a power supply which will increase the voltage as contamination build up occurs on the in-flame sensor electrode thereby keeping a constant sensor current and enabling the sensor to perform as intended even though insulative contaminant build up is present on the electrode.

Abstract: The present invention relates to an electronic circuit for measuring small amounts of charge or small electrical currents. One embodiment of the present invention provides an electronic circuit for measuring current or charge that can be used with a variety of sensing media (including high impedance sensing media) that produce a signal by either charge or current production or induction in response to physical phenomena occurring within the sensing media. In another embodiment, the voltage level (bias) of either the sensing or reference electrode can be switched relative to the other upon receipt of a triggering pulse. This changes the polarity of the electric field to cause charge of the opposite polarity to be driven to the sensing electrode, thereby eliminating the need to electrically connect a discharge path to the sensing electrode to clear the charge accumulated at the sensing electrode.

Abstract: A radiation detector including a chamber capable of being filled with an ionizable and scintillating substance, and a radiation entrance arranged such that radiation can enter said chamber partly for ionizing said ionizable and scintillating substance, partly for being converted into light therein, is disclosed. The detector further includes a light detector for detection of said light, and an electron avalanche detector for avalanche amplification and detection of electrons released as a result of the ionization. Further, there are provided means for correlating detected light and detected electrons, which are derivable from a single radiation photon; and means for producing a signal from the correlated detected light and detected electrons. The detector is particularly suitable for positron emission tomography (PET).

Abstract: A detector unit for two-dimensional detection of incoming radiation from an X-ray source, primarily for use in X-ray radiography. The unit includes a solid material structure (2) having a plurality of passages (6) extending therein and comprising surface portions (7) comprising a conversion medium. The surface portions of the passages are inclined, so that the incoming radiation impinges at an acute angle onto the surface portions. In this way, the efficiency of the detector and the positional resolution are improved.

Abstract: The invention relates to an ionization chamber for radiometric measuring instruments, specially for transversal surface measurement systems, comprising a housing with filling gas therein, having at least one radiation input window and a plurality of collector electrodes in the housing with insulated, outward leading electrical connections, whereby an electrical potential difference (voltage) exists between the housing and the collector electrodes. The inventive device enables an ionization chamber for radiometric measuring instruments to be created, specially for transversal surface measurement systems. Said chamber is sufficiently sensitive and meets the usual high requirements of ionization chambers with regard to vacuum-tightness, base current and temperature dependency.

Abstract: An x-ray fluorescence instrument for measuring the presence of lead in a sample. The lead is bombarded with gamma rays from a source thereof and in turn, emit x-rays. The x-rays are detected by a scintillation detector which emits photons that are directed to a photomultiplier tube which provides signals to an electronic processor including multichannel analyzers to provide output signals representative of the lead present in the sample. The instrument includes a cone plug disposed between the gamma ray source and the detector to prevent gamma rays from directly striking the detector.

Abstract: A photo-ionization detector (PID) includes an ultraviolet (UV) lamp that transmits UV light into an ionization chamber to ionize volatile gases. An ion detector in the ionization chamber includes interdigital electrodes that collect resulting ions using an electrical field perpendicular to the UV light propagation. A pump in the PID circulates gases through the ionization chamber in a direction perpendicular to the electrical field and to the UV light propagation. The PID additionally provides a UV monitor having interdigital electrodes that release electrons when struck by the UV light. The size of a monitor current in the UV monitor indicates the intensity of the UV light. The UV monitor is in a UV monitor chamber that protects the UV monitor from exposure to the ionized gases and improves the accuracy of UV intensity measurements.

Abstract: The coplanar interdigitated grid technique with single electrode readout provides substantial spectral performance improvement over that of conventional full-area planar electrode detectors and over coplanar interdigitated grid detectors which measure the difference between the induced charge signals from two interdigitated coplanar grid electrodes. The signal from only one interdigitated grid electrode is read out. The signal response is optimized by changing the relative areas of the two grid electrodes and the bias applied across the detector. Only one preamplifier is needed and signal subtraction is not necessary. This eliminates the electronic noise contribution from the additional preamplifier used in the normal coplanar grid implementation, and conventional single-amplifier detector electronics can be used.

Abstract: The present invention relates to a device for measuring an absorbed dose in an ionizing radiation field, and to a sensitive medium for use in an ionization chamber. The device includes a detector body (11) which is of the ionization chamber type and comprises two mutually spaced electrode elements (20, 30) and means (50) which together with the electrode elements delimit in the detector body a measuring first chamber (40) for a sensitive medium. A second chamber (60) is disposed in spaced relationship with the measuring chamber, and a flow channel (61) extends through one of the electrode elements such as to connect the measuring chamber with the second chamber. The sensitive medium is a liquid. According to the invention, the sensitive medium is a mixture of isooctane (C8H18) and tetramethylsilane (Si(CH3)4).

Abstract: A system for obtaining improved resolution in room temperature semiconductor radiation detectors such as CdZnTe and Hgl.sub.2, which exhibit significant hole-trapping. A electrical reference plane is established about the perimeter of a semiconductor crystal and disposed intermediately between two oppositely biased end electrodes. The intermediate reference plane comprises a narrow strip of wire in electrical contact with the surface of the crystal, biased at a potential between the end electrode potentials and serving as an auxiliary electrical reference for a chosen electrode--typically the collector electrode for the more mobile charge carrier. This arrangement eliminates the interfering effects of the less mobile carriers as these are gathered by their electrode collector.

Abstract: Electron capture detector for use with an effluent stream from a gas chromatograph includes an electron source means and an adjacent ionization chamber in which electron capture takes place. The active region of the ionization chamber is disposed to receive free electrons and a flow of purge gas. The detector has an inlet port for receiving a sample gas as well as an outlet port for exhausting the sample gas and the purge gas. A collector electrode in the detection chamber is biased so as to collect the free electrons in the absence of electrophilic substance. Electrophilic substances in the detector will reduce the flow of electrons to the collector and generate an ionic current. An insulative member in the form of a flow guide may be located at the portion of the anode so as to permit pulsing of free electrons to the anode but substantially block the ionic current, i.e., to discriminate between the free electrons and the ionic current.

Abstract: A "blink" technique, analogous to a person blinking at a flash of bright light, is provided for mitigating the effects of single event current latchup and prompt pulse destructive radiation on a micro-electronic circuit. The system includes event detection circuitry, power dump logic circuitry, and energy limiting measures with autonomous recovery. The event detection circuitry includes ionizing radiation pulse detection means for detecting a pulse of ionizing radiation and for providing at an output terminal thereof a detection signal indicative of the detection of a pulse of ionizing radiation. The current sensing circuitry is coupled to the power bus for determining an occurrence of excess current through the power bus caused by ionizing radiation or by ion-induced destructive latchup of a semiconductor device.

Abstract: A radiation monitoring system and method characterized by the use of paired active and passive radiation detectors to monitor exposure to a radiation field. The active detector provides an output representative of radiation exposure on a real time basis while the passive detector is readable on a delayed basis after exposure to radiation for a period of time to provide an output representative of radiation exposure over said period of time. Respective readers are provided for extracting the radiation exposure information from the detectors, as is a processor which determines a quantity of radiation exposure from the radiation information extracted from the detectors. The processor corrects radiation exposure data derived from one of the detectors using radiation exposure data derived from the other of the detectors.

Abstract: A surface ionization detector for detecting organic molecules such as illicit drugs and non-organo-nitrate explosives includes a heated surface and a collector electrode. A sample containing trace amounts of the organic molecules in ambient air is directed over the heated surface maintained at a temperature in the range of 500.degree. C. to 800.degree. C., thereby causing the molecules to decompose into fragments. A polarization voltage between 18 V and 24 V is applied to ionize the fragments which are then collected by the collector electrode. An electrometer connected to the collector electrode measures the current and a change in the current indicates the presence of ionized fragments, and thereby indicates the presence of the organic molecules. The temperature of the heated surface and the polarization voltage are optimized for detection of particular organic molecules.

Abstract: A hot cathode ionization pressure gauge with the following electrodes, arged at a distance from one another in the specified sequence along an axis:a) a thermionic cathode filament which has a central active part and lateral support parts;b) an essentially flat, diaphragm-like control electrode,c) an essentially flat apertured acceleration electrode andd) an essentially flat ion collector electrode,and with a base plate on which the control electrode, the acceleration electrode and ion collector electrode are mounted, in each case via support means running at right angles to the main part of the relevant electrode and via a support bolt connected to the support means.

Abstract: A fire detector includes a scattered light detector unit and an ionization detector unit which are arranged upon a common base at each side of the center axis of a compartment defined by the base and a peripheral wall extending from the base. The scattered light detector includes a light source and a receiver, with their principal axes intersecting in a point of intersection which is positioned at one side of the center axis of the compartment and thus extends eccentric to the center axis. The ionization detector unit includes a holder for a preparation to be ionized, with the holder being arranged at the other side of the center axis. Suitably, a heat detector is further provided in the center axis.

Abstract: A position sensitive detector has one or more wedge-and-wedge anode units, each of which has four electrodes on a planar surface arranged in a plurality of sets of four wedge-shaped electrode elements each, with the sets extending across the anode unit. Two of the electrode elements become progressively wider from set to set from one side of the anode unit to the other, while the other two electrode elements become progressively narrower. The respective electrode elements in each set are electrically connected together to complete the four electrodes. The charge measured on each of the four electrodes can be utilized to determine the X and Y coordinates of an event which results in a charge cloud impacting the anode, with redundant information available from the four electrodes.

Abstract: A hot cathode ionization pressure gauge with the following electrodes, arged at a distance from one another in the specified sequence along an axis:(a) a thermionic cathode filament which has a central active part and lateral support parts;(b) an essentially flat, diaphragm-like control electrode,(c) an essentially flat apertured acceleration electrode and(d) an essentially flat ion collector electrode,(e) a base plate on which the filament, the control electrode, the acceleration electrode and ion collector electrode are mounted,wherein the base plate consists of a ceramic material and has a plurality of through holes, and each of said control, acceleration and ion collector electrodes comprises a support member having essentially a shape of an inverted "U" with first and second legs, one of said legs of each electrode support member extending through a corresponding hole of said base plate and being fixed therein.

Abstract: An optical ionization detector wherein a beam of light is split so that one arm passes through a fiber optics and the other arm passes through a gas-filled region, and uses interferometry to detect density changes in a gas when charged particles pass through it. The gas-filled region of the detector is subjected to a high electric field and as a charged particle traverses this gas region electrons are freed from the cathode and accelerated so as to generate an electron avalanche which is collected on the anode. The gas density is effected by the electron avalanche formation and if the index or refraction is proportional to the gas density the index will change accordingly. The detector uses this index change by modulating the one arm of the split light beam passing through the gas, with respect to the other arm that is passed through the fiber optic.

Abstract: The invention relates to detectors of ionizing radiation which use a photoconductor as the detecting element. The invention lies in an electrode moving in a direction OX through a photoconductive medium disposed between two grids of electrodes extending parallel to OX. During the irradiation time, the grid electrodes of one grid are raised to a positive potential relative to the electrodes of the other grid and electrons and positive ions are created in the photoconductor. The electrons are removed by maintaining the positive potential on the electrodes of said one grid for a period of time longer than the irradiation. During displacement of said moving electrode, only the positive ions give rise to current in the electrodes. The invention is applicable to radiotherapy and radiography.

Abstract: The objects of the invention are attained in an apparatus for performing a method of analysis of organic compounds in chromatography, comprising a chromatographic column sealingly connected with the housing of a surface ionization detector having coaxially arranged inside, a collector and a thermoemitter with current leads, the housing of the surface ionization detector being provided with an opening for an auxiliary gas feed line and an opening for delivering the spent gases. The thermoemitter includes a closed-end sleeve with a heating element in contact with the external non-working surface of the thermoemitter. The collector includes a hollow cylinder spaced from the inner ionizing surface of the thermoemitter, and the outlet portion of the chromatographic column being received inside and throughout the length of the collector.

Abstract: This disclosure is directed to a detector system for use in measuring while drilling (MWD) equipment. It comprises preferably duplicate chambers positioned to one another and mounted in a MWD system where they are subject to the same shock and vibration. The shock and vibration impinge on the two chambers, and cause two output signals to be formed. The two output signals are applied to a differential amplifier so that the microphonic portion of the signal is cancelled. This then leads to a differential output signal which carries in it the signals representing nuclear events detected by the similar or duplicate detector means. Alternately, a single chamber can be used if it is provided with two anode wires and they are connected to the differential amplifier for signal cancellation.

Abstract: A method and apparatus for correcting for the ballistic deficit effect that occurs when determining the spectra of radioactive substances with an ionizing radiation detector. Two pulses derived from each output pulse of the detector, each having different peaking times but both containing effects of the ballistic deficit, are compared to produce an error signal related to the difference of the peak heights of these two pulses. A part (or all) of the error signal is added to one of the pulses to produce a corrected amplitude pulse. In order to effectively compare the two pulses, each is separately stretched at its peak height. The corrected amplitude pulse is reformed for better handling by multichannel analyzer analog-to-digital converters, with a plurality of these reformed corrected amplitude pulses then being analyzed by the multichannel analyzer to achieve a nuclear spectra for which the ballistic deficit has been corrected.

Abstract: Apparatus for radiographic imaging including a multistage avalanche chamber receiving radiation from a multiplicity of radiation point sources on a sample and providing a multiple photon output indicative of the path of the emitted radiation through the avalanche chamber, image intensification apparatus receiving the photon output of the avalanche chamber, a camera receiving an output from the image intensification apparatus; image processing apparatus for receiving the camera output and carrying out a vector analysis on the information contained in the camera output in order to determine the location of the radiation emitting point source on the sample.

Abstract: A measuring device for checking of radiation fields from treatment machines for radiotherapy, comprising a measuring block (11) containing radiation detectors (1-10) arranged under a cover plate (13) provided with field marking lines (14) and energy filter (16), said detectors being connected to a readout unit for signal processing and presentation of measurement values, the arrangement of the radiation detectors in the block and the signal processing in the readout unit being such that the dose monitor calibration, the homogeneity of the radiation field, the geometrical correspondence of the radiation field and the light field, and the radiation energy can be checked simultaneously in one single irradiation of the measuring block and subsequent reading of the measurement results.

Abstract: A multi-zoned x-ray exposure detector for a scanning fan beam x-ray system comprises an electron emitter which upon exposure to x-rays emits electrons into a channel defined by an isolation walls. The channel contains air which is ionized. The isolation walls extend parallel to the direction of the sweeping fan beam behind the electron emitter. Within each channel formed by the isolation walls, is a collection electrode biased in voltage with respect to the electron emitter to collect the ions. The intersection of the beam and the channel defines a zone in which exposure may be determined.The current from the collection electrode is amplified by an amplifier to produce a signal related to x-ray exposure of each zone.

Abstract: An ionizing radiation detector is provided which is based on the principle of analog electronic integration of radiation sensor currents in the sub-pico to nano ampere range between fixed voltage switching thresholds with automatic voltage reversal each time the appropriate threshold is reached. The thresholds are provided by a first NAND gate Schmitt trigger which is coupled with a second NAND gate Schmitt trigger operating in an alternate switching state from the first gate to turn either a visible or audible indicating device on and off in response to the gate switching rate which is indicative of the level of radiation being sensed. The detector can be configured as a small, personal radiation dosimeter which is simple to operate and responsive over a dynamic range of at least 0.01 to 1000 R/hr.

Abstract: A high resolution directional gamma ray detector includes a thin piece of foil, such as tantalum, which reacts with gamma rays incident to the edge of the foil to generate electron/positron pairs. Gamma rays originating from directions other than a direction of interest are shielded from the foil by shielding plates. An opening between the foil by shielding plates. An opening between two collimating plates permits passage of gamma rays originating from a direction of interest and allows gamma rays originating from a direction of interest to react with the foil. The generated electron and positron cause ionization in a plurality of cells. Signals resulting from these ionizations are processed by an electronic computation system through the use of coincidence processing to determine whether the signals are the result of a reaction between the foil and a gamma ray which passed through the collimator opening.