Abstract: A spark discharge trace element detection system is provided which includes a spark chamber including a pair of electrodes for receiving a sample of gas to be analyzed at no greater than atmospheric pressure. A voltage is provided across the electrodes for generating a spark in the sample. The intensity of the emitted radiation in at least one primary selected narrow band of the radiation is detected. Each primary band corresponds to an element to be detected in the gas. The intensity of the emission in each detected primary band is integrated during the afterglow time interval of the spark emission and a signal representative of the integrated intensity of the emission in each selected primary bond is utilized to determine the concentration of the corresponding element in the gas.

Abstract: Quantum detection efficiency and spatial resolution in a kinestatic charge detector are improved by utilization of an x-ray transmissive device positioned within a collection volume of a kinestatic charge detector x-ray detection chamber for displacing the charge carrier generating medium within predetermined areas of the chamber. Within the chamber, quantum detection efficiency and spatial resolution are affected by distortion in electric field lines existing between a high voltage anode and a relatively low voltage collector electrode. The distorted field lines cause charge carriers generated in the medium by impinging radiation to impact on either the walls of the chamber or to follow non-linear paths between the point of creation and the collection electrode. By displacing the medium in the chamber in areas having the greatest electric field distortion, the quantum detection efficiency and spatial resolution are improved.

Abstract: An ionization detector comprises a substrate having detector traces adjacent conductive grounded traces to minimize crosstalk and charge leakage between the detector traces and to reduce the effects of contamination and humidity.

Abstract: A diagnostic whole body counter includes both a detector for external or beta radiation and a detector for internal or gamma radiation. A subject stands on a platform and external radiation detectors inset in a back wall of the radiation detector are employed to quickly check for any external radiation on the subject. After it is determined that no external radiation is present, the subject is scanned using an internal radiation detector which is transported vertically along the length of the subject. An intrinsic germanium detector is employed as the internal radiation detector to provide a highly accurate determination of radiation dosage. Variable diameter lead collimators are positioned in front of the internal radiation detector to vary the size of the area scanned by the internal radiation detector.

Abstract: An ionization monitor measures extremely small currents using a resistor containing a beta emitter to generate ion-pairs which are collected as current when the device is used as a feedback resistor in an electrometer circuit. By varying the amount of beta emitter, the resistance of the resistor may be varied.

Abstract: In an ionization type detector for high energy radiation wherein the energy of incident radiation is absorbed through the ionization of a liquid noble gas and resulting free charge is collected to form a signal indicative of the energy of the incident radiation, an improvement comprising doping the liquid noble gas with photosensitive molecules to convert scintillation light due to recombination of ions, to additional free charge.

Abstract: A system for indicating cracks in a hollow aircraft blade, such as a helicopter blade. A system wherein a pressure differential is maintained within the blade with respect to the ambient atmosphere and including a pressure sensor for mounting on the blade in communication with the interior of the blade and having a member which moves in response to pressure changes within the blade, a beta radiation source mounted on the member and disposed for radiation transmission to a detector, a beta radiation detector for mounting on a nonrotating portion of the aircraft for receiving radiation from the source, and circuitry having the output of the detector as an input and providing an output which varies as a function of the position of the pressure sensor member for indicating the pressure condition within the blade. An improved beta radiation detector housing which substantially eliminates detector sensitivity to radar transmissions while maintaining sensitivity to nuclear radiation in the beta range.

Abstract: A power supply for a gamma radiation detector, or other detector device electrically detecting the aperiodic occurrence of a phenomenon, comprises a free-running oscillator periodically outputting, at a low repetition rate, pulses having short widths and long intervals between them; a capacitor chargeable to the detector operating voltage for operating the electrical detector device; a charging circuit coupling the oscillator to the capacitor for charging same by the pulses periodically outputted by the oscillator, the capacitor being partially discharged by the detector device upon a detection of the phenomenon; and an oscillator control effective, upon a detection of the phenomenon by the detector device, to trigger the oscillator to immediately output a pulse for recharging the capacitor.

Abstract: A wide range radiation dose rate meter for civil defense use, including a iger-Mueller tube used in a continuous counting mode and for measuring dose rates from the natural background to about 30. rads/hr., with an ion chamber arranged to measure higher dose rates up to 10,000 rads/hr. The instrument has a sample and record capability in which the selected radiation detector will have its output connected to a selected storage capacitor for a precise interval of time determined by a timing circuit and the storage capacitor will accumulate and hold a voltage proportional to the dose rate, which can be read by means of an electrometer at a later time. The instrument has a self contained hand cranked power supply and all components are selected for long shelf life.

Abstract: An x-ray detector for use in computerized tomography employing a liquefied xenon as a high density detecting medium comprises a housing having an x-ray permeable window and containing at least one electrically conductive voltage plate spaced from, and parallel to, at least one collector plate comprising a plurality of conductive elements. The liquid xenon fills the space between the voltage and collector plates.

Abstract: A substrate penetrates a main seal in an ionization chamber filled with pressurized gas. In one form of the present invention, a second chamber is provided around the region of penetration. The substrate then also penetrates the second chamber. The second chamber is pressurized with a gas at a lower pressure than in the ionization chamber. Thus, the pressure differential across the main seal is lowered, thereby reducing the load on the main seal.

Abstract: A high resolution x-ray detector for medical computerized tomography systems is filled with a high pressure noble gas as a detecting medium. The detector comprises a housing having an x-ray permeable window and containing at least one electrically conductive voltage plate and at least one collector plate comprising a plurality of conductive elements. The gaseous detecting medium, such as xenon, occupies the space between the voltage and collector plates.

Abstract: A technique for detecting the spatial distribution of propagating energy induces secondary energy produced in a detector to drift in a predetermined direction at a predetermined velocity and synchronously moves the detector in a direction opposite to the direction of drift of the secondary energy at a velocity equal in magnitude to the magnitude of the velocity of drift of the secondary energy. Although the secondary energy is drifting with respect to the detector, the synchronous detector movement causes the secondary energy to appear stationary with respect to a source of radiation, resulting in "kinestatis" of the secondary energy. The secondary energy resulting from the radiation integrates along stationary paths in the detector (operated as a "kinestatic detector") and is subsequently detected when a collection volume of the detector sweeps through the stationary secondary energy.

Abstract: Proportional counters for the detection and measurement of radioactive surface contaminations are provided with at least two flat window faces enclosing an angle and being formed by a thin foil spread or stretched by a framework including thin rods arranged along the inner edges of contacting window faces, to which rods the foil may be adhered. A perforated lattice or grid cage serves in particular to protect the thin window against any contact, the cage provides for a spacing of about double rod thickness between the framework and the controlled surface. Preferred is a polygonal and in particular hexagonal lattice whose grid wires or strips do not lie in the main scanning direction. Particularly convenient for checking pipelines are, for example, cylindrical measuring probes comprising window foils extending over and perhaps adhered to a circularly arranged frame of thin rods.

Abstract: A multi-channel electrophoresis apparatus is fitted with a detection means disposed substantially across the width of the medium, intersecting all channels. The detection means senses components of samples as they migrate past the detection means and identifies the channel in which the detected components are located. In the preferred embodiment, the samples are tagged with radioisotopes which are detected by the detector.

Abstract: An improved ion detector device of the ionization detection device chamber ype comprises an ionization chamber having a central electrode therein surrounded by a cylindrical electrode member within the chamber with a collar frictionally fitted around at least one of the electrodes. The collar has electrical contact means carried in an annular groove in an inner bore of the collar to contact the outer surface of the electrode to provide electrical contact between an external terminal and the electrode without the need to solder leads to the electrode.

Abstract: To enable an ionization chamber used for measuring the intensity of a beam of ionizing radiation, for example an electron beam produced by a linear accelerator and used for radiotherapy, both to give an output signal which is independent of ambient pressure and temperature and to present a low weight of scattering material per unit area to the beam, the chamber is of flexible construction so that the volume of gas in it adapts to ambient pressure and temperature, and such that the weight of gas in the active region between the electrodes per unit area remains substantially constant. Suitably, the electrodes are conductive layers on flexible plastics sheets, an outer annular portion of one sheet providing a flexible connection between two opposed chamber wall portions which remain substantially planar and parallel; the proportional change (.DELTA.V.sub.1 /V.sub.1) in a volume bounded by the opposed wall portions and including the active region equals the proportional change (.DELTA.V.sub.2 /V.sub.

Abstract: Pulse pile-up rejection in nuclear and X-ray spectrometry is reduced or eliminated by providing the low-pass filter with a storage element which is charged to the value substantially by the voltage step generated by a quantum of radiation before the filtering process commences and only then effecting the filtering process. The step values before and after the rise of the step can be detected and with storage of the previous value, the energy proportional output can then be detected as the difference. The method and apparatus eliminates the rise time of the storage element as a factor contributing to pulse pile-up.

Abstract: In an invention detector having an array of detectors, grounding pads are positioned in the spaces between some detectors (data detectors) and other detectors (reference detectors). The grounding pads are kept at zero electric potential, i.e., grounded. The grounding serves to (1) drain away electrons and thereby prevent an unwanted accumulation of charge in the spaces, and (2) cause the electric field lines to be more perpendicular to the detectors in regions near the grounding pads.

Abstract: An apparatus for detecting propogating energy in a defined space includes a medium disposed within the space which interacts with the incident propogating energy to produce secondary energy. An electrostatic field is impressed across the defined space for directing the secondary energy toward a planar detector located at one end of the space. Adjacent the detector is positioned a planar grid for preventing the secondary energy from being detected by the detector prior to passage through the grid. The grid comprises a three layer device having a middle layer formed of an electrically insulative sheet material of a relatively stiff structure. The other two layers comprise conductive layers on opposed surfaces of the first layer which are connected to an electric potential for creating a field across the grid structure and a further field between the grid structure and the detector for accelerating the secondary energy toward the detector in the area of the grid at a space between the grid and detector.

Abstract: Apparatus and method for electronically reading planar two dimensional .beta.-ray emitter-labeled gel electrophoretograms. A single, flat rectangular multiwire proportional chamber is placed in close proximity to the gel and the assembly placed in an intense uniform magnetic field disposed in a perpendicular manner to the rectangular face of the proportional chamber. Beta rays emitted in the direction of the proportional chamber are caused to execute helical motions which substantially preserve knowledge of the coordinates of their origin in the gel. Perpendicularly oriented, parallel wire, parallel plane cathodes electronically sense the location of the .beta.-rays from ionization generated thereby in a detection gas coupled with an electron avalanche effect resulting from the action of a parallel wire anode located therebetween. A scintillator permits the present apparatus to be rendered insensitive when signals are generated from cosmic rays incident on the proportional chamber.

Abstract: A Geiger-Mueller tube includes a tubular, stainless steel cathode (A) which defines a chamber (B) therein. An anode (C) extends axially through the chamber in a spaced relationship with the cathode. A thin layer of rhenium (20) is plated on an interior surface (12) of the cathode. End caps (32, 36) and ceramic fittings (34, 38) hermetically seal the ends of the cathode tube. The cathode chamber is charged with a gaseous mixture including in primary part noble gases, such as neon and argon, and about 1-3% bromine or other halogen gases. The Geiger-Mueller tube with a rhenium plated cathode is relatively inexpensive to manufacture, provides excellent bromine and halogen degradation resistance at elevated temperatures, and provides superior, linear operating characteristics over a wide range of temperatures.

Abstract: A neutron ionization chamber of the gamma ray compensation type comprises a neutron-sensing ionization chamber portion having an electrode surface coated with a material for sensing neutrons, a gamma ray-sensing ionization chamber portion which has a low neutron sensitivity in comparison with the neutron sensitivity of said neutron-sensing material, a device for substracting ionization currents in the gamma ray-sensing ionization chamber portion from ionization currents in the neutron-sensing ionization chamber portion, and a coating material which is coated on an electrode surface of the gamma ray-sensing ionization chamber portion, the coating material including a material for sensing neutrons the percentage of which is less than the the percentage of the neutron sensing material of the neutron sensing ionization chamber portion.

Abstract: An integrated radiation detector comprises a number of electrode plates assembled at a mutual distance. The electrode plates comprise slots in which electrically insulating gas-tight strips projecting through all the electrode plates are provided, of which strips one serves as an input window and the remaining strips serve as walls of the detection spaces. For sealing, the strips are interconnected, for example, by means of electrically insulated glued joints. Since the detector need no longer be assembled in a gas-tight housing, connections for the electrodes can be realized in a simple manner. Parts of the electrodes projecting beyond the actual detection space on the side of the input window may serve a collimator for the incident radiation.

Abstract: A directional gamma ray monitor is based on a method for measuring the gamma ray flux within a small solid angle. The method entails measuring the flux incident on a detector 36, measuring the flux incident on the detector 36 when behind a shielding block 50, which is arranged to subtend the said small solid angle with the detector 36, and determining the difference between the two measurements. In an apparatus for carrying out the method, the shielding block 50 is moved between a position when it is on the axis of a gamma ray detector 36 and a position where it is displaced from the axis of the gamma ray detector 36.

Abstract: Disclosed is a dosimeter-radiation meter for measuring a dose flow of ionizing radiation including a Geiger-Mueller tube and data processing circuitry. The data processing circuitry comprises a circuit for shaping and amplifying the pulses delivered by the tube, circuits for storing digital representations of characteristic parameters associated with a particular Geiger-Mueller tube, a section circuit for applying either sensed pulses or the coded parameters to a calculation unit, a calculation unit for counting pulses and for correcting the pulse count according to the precoded stored parameters and a display unit for displaying the dose count or flow rate.

Abstract: A process for precision measurement of charged particle emissions from a surface and an apparatus for providing a high resolution digital image of the distribution of such emissions in a minimum exposure time over a relatively large surface area. The process of measurement uses the direction of emissions as determined by two or more position measuring elements of an area detector. The apparatus is based on multiple region detector elements that employ proportional amplification of ionization in a gas.

Abstract: A gated strip proportional detector includes a gas tight chamber which encloses a solid ground plane, a wire anode plane, a wire gating plane, and a multiconductor cathode plane. The anode plane amplifies the amount of charge deposited in the chamber by a factor of up to 10.sup.6. The gating plane allows only charge within a narrow strip to reach the cathode. The cathode plane collects the charge allowed to pass through the gating plane on a set of conductors perpendicular to the open-gated region. By scanning the open-gated region across the chamber and reading out the charge collected on the cathode conductors after a suitable integration time for each location of the gate, a two-dimensional image of the intensity of the ionizing radiation incident on the detector can be made.

Abstract: A process for the examination of the flat radiograph of an object irradiated with the aid of an ionizing radiation source is disclosed. In an ionization chamber is detected the latent image of the object formed by the different electrical charges produced in the volume of the chamber under the influence of the impact of the radiation flux which has traversed the object. As this irradiation is continuous, the object to be examined is moved relative to the ionization chamber in the direction and at the migration speed of the ions formed in the electrical field thereof.

Abstract: A beta radiation particle detector having a housing that is substantially impervious to beta radiation particles and which surroundingly encompasses an ionization chamber which is defined by electrically conductive walls is disclosed. The walls terminate in an edge which defines an opening into the ionization chamber with the opening being covered by a beta radiation pervious electrically conductive window that entraps, within the ionization chamber, a quantity of gaseous molecules which are adapted to ionize upon impact with a beta radiation particle. An electrode is disposed within the ionization chamber and has a generally shallow concave surface having a width which is substantially greater than its depth and which faces the electrically conductive window.

Abstract: A detecting head assembly provides output signals relating to individual ionizing events due to radioactive decay of material in a medium such as a radiochromatogram or electrophoretogram. The detecting head assembly comprises a scanning head which includes an ionization chamber comprising two spaced detecting electrodes each including an array of spaced conductors. The conductors extend transversely of one another to provide a plurality of conductor crossing points. A mask having a plurality of radiation transmissive zones or apertures is supported relative to the detecting electrodes such that said zones or apertures respectively correspond with the conductor crossing points.

Abstract: A hand-held radiation detector for measuring localized radiation at extremely low levels of the order of 1 CPM (counts per minute); an anode is provided in the form of a needle within a sealed chamber defined by a generally cylindrical housing having a metallized radiation window on one end; a focusing arrangement is utilized which enables efficient focusing of the electric field, such that avalanche and efficient electron multiplication occurs within the chamber responsive to the localized radiation entering the chamber, the focusing arrangement including (1) a needle point design to concentrate electric field lines on and in the immediate vicinity of the point, (2) a judiciously selected location for the needle at a sufficient distance from the radiation window such that the electric field lines emanating from the window are forced into the amplifying region (AR) of the needle, and (3) a suitably configured cathode defined by the radiation entrance window and the upper conducting tubular member of the housi

Abstract: The invention substantially eliminates measurement errors in radiation field strength due to circuit propagation time delays and slow drift conditions, Geiger-Mueller tube turn-on time and response curve variations, and the need to manually calibrate the measurement apparatus in high radiation fields to compensate for time errors. The exponential probability function has the property that the expected value for the arithmetic mean of any right hand segment of the curve is always the same provided that the axis is adjusted so that the starting point of the selected segment is zero. The curve is trimmed dynamically each time a new rate is calculated. An individual count of strike events is kept for N separate but consecutive time units, and the counts for the later occurring events are lumped together as the Main Event. After the data collection period ends, a total accumulated time and accumulated count are constructed. This construction begins by examining the Main Event data.

Abstract: Disclosed is an alpha monitor usable in an automated nuclear fuel pin loading and processing unit. Fuel pins or other elongated pins are fed laterally into the alpha monitor in a singular fashion and are translated by a first roller assembly into a weld flare machining and decontamination substation not forming a part of the invention. Pins return and are lifted upwardly and transferred across to a combined pin lifting and electrode operating means which lifts the pins upwardly into a clamshell electrode assembly which is spread open by a combined pin lifting and electrode operating means. Once inserted the clamshell type electrode arrangement closes around the fuel pins so that inspection can occur. Fuel pins are inspected by charging electrodes to a negative potential and measuring the change in charge occurring when positively charged alpha particles strike the negatively charged electrodes.

Abstract: A multi-cell radiation detector constructed such that a first group of electrodes to which is applied high voltage and a second group of electrodes to which are connected signal leads are alternately arranged inside a vessel containing ionizable gas enclosed therein. The first group electrodes are provided with terminals to which are connected leads for introducing high voltage from the exterior, while the second group electrodes are provided with terminals to which are connected leads for leading out signal outputs to the exterior. These leads and terminals are all disposed at positions offset from traveling path of the radiation so as to reduce the volume of the space under the weak electric field behind the electrode section.

Abstract: A pressure vessel of an X-ray detector, in which the contamination and leakage of xenon gas contained in the detector is prevented. The pressure vessel of the invention comprises a container of a curved pillar shape with a window through which the X-ray passes. The container is made of a metal, and the window faces inward of the curvature of the container. A carbon fiber-reinforced plastic sheet is fixed to the inner wall of the periphery of the window to cover the window. An elastic insulation sheet is attached to the inside of the carbon fiber-reinforced plastic sheet so as to cover the window. A metal foil is attached to the inside of the elastic insulation sheet so as to cover the window.

Abstract: Body structures into which a gamma-emitting isotope has been introduced are investigated using an imaging system comprising in sequence a collimator, a first detector, a filter, and a second detector. The first detector is partially transparent to the emerging photons and the filter is adapted to have an absorption edge energy fractionally less than the energy of the radioactive isotope source. The first detector produces an image of both scattered and non-scattered photons and the second detector simultaneously produces an image of only the scattered photons. The two images can be manipulated to produce an image due only to non-scattered photons which is the image of interest.

Abstract: A radiation detector has a housing in which is sealed a gas to be ionized when X-rays are projected therein. A plurality of electrodes for detecting the X-rays are arranged in the housing, and the housing is curved with a fixed curvature along the arranged direction of the electrodes. A vessel portion of the housing is closed by a cover portion. A cut extending in the longitudinal direction of the housing is formed in one side wall of the vessel portion. The cut is closed by an X-ray window. A window member of the X-ray window is made of carbon fiber reinforced plastics. The window member is bonded to the inside face of the side wall of the vessel portion, and is pressed against the inside face by the pressure of the gas sealed in the housing. Thus, the window member and the vessel portion are fully hermetically sealed. Since the X-ray transmission factor of the carbon fiber reinforced plastics is high, even low-energy X-rays can be projected with high intensity between the electrodes.

Abstract: A detector apparatus for differentiating between gamma and neutron radiation is provided. The detector includes a pair of differentially shielded Geiger-Mueller tubes. The first tube is wrapped in silver foil and the second tube is wrapped in lead foil. Both the silver and lead foils allow the passage of gamma rays at a constant rate in a gamma ray only field. When neutrons are present, however, the silver activates and emits beta radiation that is also detected by the silver wrapped Geiger-Mueller tube while the radiation detected by the lead wrapped Geiger-Mueller tube remains constant. The amount of radiation impinging on the separate Geiger-Mueller tubes is then correlated in order to distinguish between the neutron and gamma radiations.

Abstract: A Geiger-Mueller tube-based radiation measurement device includes circuitry for the correction of the dead time losses associated with the Geiger-Mueller tube. As the event count rate rises, the transfer function (e.g., the closed loop voltage gain) of an operational amplifier responding to an event count rate signal is modified to compensate for dead time losses experienced at high count rates. Preferably, an analog switch controlled by the event count rate signal automatically sets the voltage gain of the operational amplifier at a level corresponding to the desired amount of dead time compensation required to provide an accurate measurement of actual events. The dead time correction circuitry disclosed herein finds practical application in the use of well-known analog rate meter circuits of the charge pump type.

Abstract: The present invention relates to detectors used in X-ray tomographic imaging. The invention describes a xenon ionization detector having individual detector elements spaced 1.5 mil apart, thus providing high resolution. In one embodiment, a procedure is described for reducing a spurious electric current which was found to arise when such narrow spacings were used.

Abstract: This invention describes apparatus for and a method of measuring radiation field strength which uses a pulse enabled detector (e.g. G-M tube) and is based on the equation R=K/t, where R is the radiation field strength, t is the time till first strike, and K is a proportionality constant for the given apparatus. The G-M detector is enabled by pulsing the bias voltage across the detector up into its active region and then measuring the elapsed time interval to the incident of first strike. Since the reciprocal of this time is proportional to the radiation field strength, all information necessary to determine the field strength has been obtained. A constant wait time is employed after each strike to assure that the G-M tube full recovery time has expired, and the G-M tube is then enabled and the process repeated. Because of the random nature of radiation phenomena the confidence level that any given measurement is an accurate representation of the true average field strength is low.

Abstract: A radiation dosimeter includes a plurality of air wall type ionization chambers for radiation detection. Each ionization chamber is connected in series with a selectively actuable switching element under the control of a data processor. The ionization chamber switching element pairs are connected in parallel and the entire group is further connected in series with a load resistor and a source of known potential. A voltage threshold detector is connected across the load resistor and is effective to develop a signal proportional to the peak potential appearing across the load resistor when each of the switching elements is actuated to recharge the various ionization chambers. The voltage peak is proportional to the radiation rate. An A/D converter converts the output of the voltage threshold detector into useful data for a data processor which performs the functions of process control and calculation of radiation rate and cumulative dosage.

Abstract: A detector is provided comprising two insulating supports (44,46) in the form of half cylinders, provided on their cylindrical wall with a small pitch thread, said supports being fixed by their ends to a mounting frame (40) which holds them spaced apart and parallel, with their cylindrical wall turned outwardly, a cathode wire (60) being wound around the threaded portion of said supports and an anode wire being stretched inside the coil, between two terminals carried by the frame.

Abstract: A hand-powered alternator for generating an alternating voltage provides same through a rectifier to a high capacity capacitor which stores the resultant dc voltage and drives a voltage regulator to provide a constant low voltage output for a portable radiation detection instrument. The instrument includes a Geiger-Muller detector tube whose output is fed to a pulse detector and then through an event counter and LCD driver circuit to an LCD bar graph for visual display. An audio driver and an audio output is also provided. All circuitry used is low power so that the capacitor can be readily charged to a sufficient level to provide power for at least 30 minutes. A low voltage indicator is provided on the LCD display to indicate the need for manual recharging.

Abstract: A dosimeter for measuring the intensity of high energy electron, photon, or other particle radiation has ion, electron, and radiation shields about at least respectively sensitive components of the dosimeter. The entire dosimeter, therefore, can be assembled as a unit and portably placed in the radiation to be measured. Ruggedness for this desirable partability is provided by the use in the dosimeter of a pancake ionization chamber which also eliminates the need to calibrate radiologically the dosimeter.

Abstract: An imaging proportional counter which significantly reduces parallax errors when imaging point sources of radiation located at variable distances from the detector entrance window. The imaging proportional counter includes a gas filled enclosure with a concave shallowly curved radiation permeable entrance window allowing radiation from the source to enter the enclosure. A multi-wire grid assembly is spaced behind the entrance window within the enclosure. When a potential difference is applied between the grid assembly and concave entrance window an electrostatic field is generated such that near the interior surface of the window the field lines form a spherically focussed region. The concave entrance window also allows increased fill gas pressures such that radiation entering the detector will interact with the fill gas very near the entrance window while still in the spherically focussed region.

Abstract: An ion chamber exhibiting a flat response to a wide range of incident gamma energy is provided by a high-pressure fill gas mixture of a first major constituent, low atomic number gas which exhibits a reduced gamma response at low gamma energy levels, and a second minor constituent, high atomic number gas which exhibits an increased gamma response at low gamma energy levels. The preferred fill gas mixture is nitrogen as the major constituent and xenon as the minor constituent.

Abstract: A radiation dose-rate monitor is provided which operates in a conventional linear mode for radiation in the 0 to 0.5 R/h range and utilizes a nonlinear mode of operation for sensing radiation from 0.5 R/h to over 500 R/h. The nonlinear mode is achieved by a feedback circuit which adjusts the high voltage bias of the proportional counter, and hence its gas gain, in accordance with the amount of radiation being monitored. This allows compression of readout onto a single scale over the range of 0 to greater than 500 R/h without scale switching operations.

Abstract: Ionization chamber making it possible to measure high energy gamma radiation, wherein it comprises a tight cylindrical enclosure containing an ionizable gas, and several coaxial cylindrical electrodes, which are insulated from one another, and are positioned within the enclosure and are raised to different potentials, so as to produce an electrical field in the enclosure, whereby the innermost electrode is formed by a solid cylinder, the outermost electrode is formed by a solid tube and the intermediate electrodes are formed by a perforated tube.