Abstract: An apparatus includes an ion chamber and a valve assembly. The ion chamber may include a housing enclosing a gas and one or more electrodes. The valve assembly is coupled to the ion chamber allowing control of replacement of the gas within the housing.

Abstract: The purpose is to provide a discharge system which can minimize wear of a connecting part of a discharging device and a refilling device which is caused under the influence of particulate matters contained in fluid even if connection and disconnection for refilling the discharging device with the fluid is repeated. A discharge system includes a discharging device capable of discharging the fluid, and a refilling device capable of refilling the discharging device with the fluid. The fluid is suppliable from the refilling device side to the discharging device side by inserting one of a discharge-side coupler provided to the discharging device side and a refill-side coupler provided to the refilling device side into the other to connect the discharging device to the refilling device. A clearance size d formed between the discharge-side coupler and the refill-side coupler is determined based on the particle size distribution of the particulate matters that constitutes the fluid.

Abstract: Devices, systems, and methods of using one or more memristors as a radiation sensor are enabled. A memristor can be attractive as a sensor due to its passive low power characteristics. Medical and environment monitoring are contemplated use cases. Sensing radiation as part of a security system (at an airport for example) and screening food for radiation exposure are also possible uses. The memristor as a radiation sensor may possibly provide an inexpensive and easy alternative to personal thermoluminescent dosimeters (TLD). Memristor devices with high current and low power operation may be attached with wearable plastic substrates. An example device includes two metal strips with a 50 ?m thick layer of TiO2 memristor material. The device may be made large relative to traditional memristors which are nanometers in scale but its increased thickness can significantly increase the probability of radiation interaction with the memristor material.

Abstract: A Geiger-Muller counter tube includes an enclosing tube, an anode conductor, a cathode conductor, an inert gas, and a quenching gas. The enclosing tube is at least partially cylindrical and has a sealed space. The anode conductor includes an anode electrode and a linear first metal lead portion. The anode electrode is arranged inside the space and formed in a rod shape. The first metal lead portion is connected to the anode electrode and supported at an end of the enclosing tube. The cathode conductor includes a cylindrical cathode electrode and a linear second metal lead portion. The cathode electrode surrounds a peripheral area of the anode electrode inside the space. The second metal lead portion is connected to the cathode electrode and supported at the end of the enclosing tube. The cathode electrode has a side surface through a part of which a through-hole passes.

Abstract: A radiation measurement apparatus for measuring radiation includes a first and second Geiger-Muller counter tubes and a radiation-direction calculating unit. The first Geiger-Muller counter tube seals an electrode within a circular pipe-shaped enclosing tube that extends in a straight line. The first Geiger-Muller counter tube is arranged along a first direction. The second Geiger-Muller counter tube seals an electrode within a circular pipe-shaped enclosing tube that extends in a straight line. The second Geiger-Muller counter tube is arranged in a second direction intersecting with the first direction. The radiation-direction calculating unit is configured to compare a first detection signal and a second detection signal with one another to calculate a direction of radiation to be emitted from the sample. The first detection signal is output from the electrode of the first Geiger-Muller counter tube. The second detection signal is output from the electrode of the second Geiger-Muller counter tube.

Abstract: A position-sensitive radiation counting detector includes a first and a second substrate. A gas is contained within the gap between the substrates. A photocathode layer is coupled to the first substrate and faces the second substrate. A first electrode is coupled to the second substrate and a second electrode is electrically coupled to the first electrode. A first impedance is coupled to the first electrode and a power supply is coupled to at least one electrode. A first discharge event detector is coupled to one of the electrodes for detecting a gas discharge event in the electrode. The radiation counting detector further includes a plurality of pixels, each capable of outputting a gas discharge counting event pulse upon interaction with radiation received from the photocathode. Each gas discharge pulse is counted as having an approximately equal value.

Abstract: The present disclosure relates to an ionization chamber with a built-in temperature sensor, which is especially adapted for devices, such as X-ray units, gamma irradiators and linear accelerators, whichever is used for performing radiation dose output measurement accordingly. In an embodiment, the ionization chamber comprises: a cavity, an inner electrode, a chamber wall, an outer electrode, a guard electrode and a calibrated temperature sensor for detecting real-time temperature inside the cavity of ionization chamber to be used in the correction process of radiation dose measurement signals. With the aforesaid device, not only the accuracy of measurement can be improved effectively, but also the time consumed in a radiation dose measurement period can be reduced greatly since it will no longer bear the disadvantage that the radiation dose measurement has to wait until the temperatures inside and outside the cavity of ionization chamber had reached a thermal equilibrium before the measurement.

Abstract: The gas filled in an envelope contains nitrogen and hydrogen. The nitrogen used as a supplementary gas is not polymerized even when radiation is applied to it, and serves to achieve higher resolution than in the case where carbon dioxide is used as the supplementary gas. The hydrogen can reduce the change of gas gain.

Abstract: The invention comprises a radiation and contamination monitor for the monitoring of radiation and contamination. The instrument is intrinsically safe and comprises a radiation detector, a power source, a signal processor and a display, said power source, signal processor and display being housed within a sealed instrument housing formed from a non-metallic material which is resistant to static discharge. The detector may be housed in a detachable housing for contamination monitoring.

Abstract: The invention is a digital radiation detector utilizing the stable timing functions of a microcontroller or plurality of microcontrolling devices to perform three independent functions. A first timer generates a continuous square wave output that is fed through a class B amplifier to yield a stable, drift-free power supply for a connected radiation sensor. A second timer is used as an event counter for counting the processed pulses coming from the radiation sensor. A third timer acts as a real time clock generating a one-second interrupt for quantifying the number of counts per second. The number of counts per second can be communicated as raw data through a communication interface or presented as a number of audible or visual displays.

Abstract: A G.M. tube environment radiameter including a sensitivity degradation monitoring device, comprising: a cyclic counter circuit for counting the pulses coming from the G.M. tube; b) a power operated moveable support for a weak radioactive source, adapted to alternatively move said source between two stable positions, a first position in which the source is reproducibly located close to the G.M. tube so as to cause it to generate pulses of the same magnitude order as the pulses generated under action of the standard background environment radioactivity, and a second position in which the source intensity is negligible with respect to the one caused by the standard background radioactivity; a circuit for measuring and storing the pulse intensities generated by the radioactive source when it is close to the G.M. tube, both in the test stage and in subsequent times as well as for performing the ratio of said pulse intensity values.

Abstract: A vacuum ionization gauging tube, particularly a Bayard-Alpert (B-A) type vacuum ionization gauging tube, has a firmly compact construction, and provides the capabilities for minimizing outgassing gases and measuring pressures accurately without affecting the ultimate pressure range. The B-A vacuum ionization gauging tube includes a filament having a total surface area of between 6 mm.sup.2 and 20 mm.sup.2, a grid formed like a coil from a 0.1 mm to 0.3 mm diameter metal wire, the coil having a diameter of 5 mm to 7 mm and a length of 15 mm to 20 mm and across which it can be energized, an ion collector electrode having substantially the same length as the filament, and a metal envelope for enclosing the above electrode elements and which is maintained at a potential lower than that of the filament. The grid coil has a winding pitch of between 1.5 mm and 2.5 mm. The filament and grid are spaced apart from each other by the distance of between 2 mm and 4 mm.

Abstract: The present invention is a thin filament embedded in a low density aerogel for use in radiation detection instruments and incandescent lamps. The aerogel provides a supportive matrix that is thermally and electrically nonconductive, mechanically strong, highly porous, gas-permeable, and transparent to ionizing radiation over short distances. A low density, open-cell aerogel is cast around a fine filament or wire, which allows the wire to be positioned with little or no tension and keeps the wire in place in the event of breakage. The aerogel support reduces the stresses on the wire caused by vibrational, gravitational, electrical, and mechanical forces.

Abstract: A gamma-ray compensated ionization chamber wherein the state of compensating a gamma-ray is controlled by utilizing the effect that a change in the applied voltage ratio of a high-voltage electrode to a compensating electrode changes the form of an electric field around the holes in a signal electrode.

Abstract: The invention relates to a method and an apparatus for qualifying the operation of a radiation (e.g. neutron) detector containing an ionizable gas (e.g. He.sub.3), such as a detector disposed in a logging sonde designed to be lowered in a well, wherein a radioactive source capable of ionizing said gas is disposed inside the detector. From the counts of the ionization pulses, one qualifies the operation of the detector. The method provides either a verification (usually performed before the logging operation, outside the well) or, when carried out while the detector is operating in the well, a stabilization of the measured spectrum.Preferably, the internal source is an alpha source comprising uranium or americium and which is disposed inside the detector in the form of a thin foil.

Abstract: The anode connections in a gas-filled X-ray detector are mounted so as to extend transversely of the anode wire so that a substantial saving as regards space is achieved. In order to reduce field inhomogeneities in the ionization space, there may be provided a field profile bush which partly encloses the anode wire and field bushes may be arranged around the anode connection pins.

Abstract: A wire chamber or proportional counter device, such as Geiger-Mueller tube or drift chamber, improved with a gas mixture providing a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor.

Abstract: A high speed curved position sensitive porportional counter detector for use in x-ray diffraction, the detection of 5-20 keV photons and the like. The detector employs a planar anode assembly of a plurality of parallel metallic wires. This anode assembly is supported between two cathode planes, with at least one of these cathode planes having a serpentine resistive path in the form of a meander having legs generally perpendicular to the anode wires. This meander is produced by special microelectronic fabrication techniques whereby the meander "wire" fans outwardly at the cathode ends to produce the curved aspect of the detector, and the legs of the meander are small in cross-section and very closely spaced whereby a spatial resolution of about 50 .mu.m can be achieved. All of the other performance characteristics are about as good or better than conventional position sensitive proportional counter type detectors. Count rates of up to 40,000 counts per second with 0.5 .mu.s shaping time constants are achieved.

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: 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: The invention relates to the examination of samples which, by thermal or photon excitation, are able to emit electrons. These electrons are detected and located by a counter incorporating a cathode forming a mesh network. Pointed anodes coincide with the axes of the meshes. The enclosure of the apparatus is sealed by the sample and its excitation means. The invention can be used in dosimetry or in the checking of surface states.

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: A gamma ray energy filter for a improving the uniformity of response of a Geiger-Muller tube comprises only two spaced filter bodies. To improve the uniformity of the energy response, the two filter bodies consist of a lead/tin alloy containing substantially less than 95% but not substantially less than 40%, and suitably 50-60%, of lead. To improve the polar response particularly in directions away from the normal to the longitudinal axis of the tube, and at quite low energies, adjacent edges of the filter bodies are inclined to the longitudinal axis over a majority of their radial thickness at less than 45.degree., and circumferentially-spaced apertures with axes inclined to the longitudinal axis are provided in at least one of the bodies.

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: 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.

Abstract: Gas-filled detector for locating the presence in space of particles or radiations. The detector according to the invention comprises a curved body containing a gaseous fluid under pressure, and being provided with a window, and on the inside, an elongated element forming means of picking-up an avalanche of elements, said means being constituted by a structure of the type with at least one curved conducting strip held in such a way by the body that it projects into the enclosure and that one of its longitudinal edges is parallel to the axis of the window. The invention finds an application in X-ray crystallography.

Abstract: In devices having several electrical connections passing through a separation wall, feedthrough is realized by means of a flexible printed tape. The printed tape includes a number of electrical conductors, and is enveloped by a polyimide carrier which constitutes with an epoxy glue a very reliable permanent seal in separation walls of both metal and ceramic materials.

Abstract: A radiation counter comprises; electrodes made of nickel base super alloy containing the nickel in the weight ratio exceeding 30% and not exceeding 90% and the chrome, the iron, etc. as the balance; and counter gas in which the argon gas is the chief ingredient and with which the nitrogen gas is mixed in the volume ratio exceeding 2% and not exceeding 30%. The counter operates stably at a high temperature exceeding 450.degree. C., affords relatively large output pulse current and has short electron-collection-time characteristics.

Abstract: A Geiger-Mueller ("GM") tube containing a noble gas mixture of about 98-99.9% Ne and the remainder Ar, and in addition containing from 2-5% ethylene as the quench gas, provides high stability and high count rates in the temperature range from about -100.degree. C. to about 200.degree. C. When this GM tube is provided with a sleeve-and-screen liner in electrical contact with an outer cathode, the tube exhibits exceptional sensitivity. The sleeve may be a continuous deposit of a heavy metal having an atomic number from about 73 to about 83, deposited on the inner surface of the cathode tube, or the sleeve may be a foil liner of tungsten or tantalum. The screen is woven of metal wire on which is deposited a heavy metal.

Abstract: A radiation detecting arrangement for measuring or counting an ionizing radiation contains a compensating filter arrangement which safequards a measurement of the radiation dose which is either independent of the energy, or independent of both the energy and the direction thereof. The compensating filter arrangement contains a supporting tube made from a slightly absorbing metal having an ordinal number not higher than about 35, which surrounds a tubular radiation detector and which, on its surface, carries several ring-shaped filter parts. These filter parts are made from one or more metal sleeves of a heavy metal or of a heavy metal alloy slipped onto the supporting tube and soldered or cemented thereto. These filter parts, as regards position and shape, are manufactured by a metal-removing process with only the supporting tube being clamped by the metal-removing machine.

Abstract: The leading edge of the plates employed in a high pressure gaseous xenon x-ray detector are tapered so as to be narrower along the edge of the plates nearest to the x-ray source. Xenon x-ray detectors produced in accordance with the present invention exhibit an increased quantum detection efficiency without a significant increase in noise due to microphonics.

Abstract: An improved particle detection tube including a method for applying a radion transparent electrically non-conductive, opaque to ultraviolet light coating to the mica window of the tube. The coating reduces erroneous counts by preventing arcing between the tube anode and window. A purified mineral bituminous hydrocarbon based wax coating is applied to the mica window by cleaning the window with a hydrocarbon or chlorinated solvent rinsing with isopropyl alcohol drying the window dissolving 4 to 20 milligrams of purified bituminous hydrocarbon based wax in 1 to 2 milliliters of a hydrocarbon or chlorinated solvent on the window, and rotating the tube until the solvent evaporates to produce a film of the wax thereon.

Abstract: Apparatus is provided for detecting radiation such as gamma rays and X-rays generated in backscatter Mossbauer effect spectroscopy and X-ray spectrometry, which has a large "window" for detecting radiation emanating over a wide solid angle from a specimen and which generates substantially the same output pulse height for monoenergetic radiation that passes through any portion of the detection chamber. The apparatus includes a substantially toroidal chamber with conductive walls forming a cathode, and a wire anode extending in a circle within the chamber with the anode lying closer to the inner side of the toroid which has the least diameter than to the outer side. The placement of the anode produces an electric field, in a region close to the anode, which has substantially the same gradient in all directions extending radially from the anode, so that the number of avalanche electrons generated by ionizing radiation is independent of the path of the radiation through the chamber.

Abstract: An ionization chamber comprises a plurality of cylindrical electrodes which are coaxially arranged, and a casing which holds the cylindrical electrodes in it under the condition allowing the axial shifting of the edges of the cylindrical electrodes but preventing the radial shifting of the cylindrical electrodes whereby the slight relative deviation of parts for the ionization chamber can be minimized during use at high temperature or during a severe thermal cycle.

Abstract: To prevent the anode wire which runs along the axis of the tube from vibrng at the end adjacent the window, a ceramic cup has a flat surface sealed to the inside of the window, and the end of the anode wire is captured within an opening of the cup.

Abstract: A highly sensitive Geiger-Mueller radiation detector with improved temperature stability and working life uses a cathode liner made of tungsten. The liner is resistant to attack by the halogen quench gases which are used in the detector. The method of conditioning the tube for use is much simpler and less expensive than it is for existing tubes.

Abstract: A highly sensitive Geiger-Mueller radiation detector with improved temperature stability and working life uses a cylindrical cathode made from a nickel copper alloy preferably containing predominantly nickel. This alloy is resistant to attack by halogen quench gases used in the tube and provides an excellent surface for the electrodeposition of platinum to provide a low porosity surface.

Abstract: A spark chamber frame 8 is manufactured using only inorganic materials. Spark chamber frame 8 includes a plurality of beams 10, 12, 14, and 16 formed from inorganic material, such as ceramic or glass, and are connected together at ends 9 with inorganic bonding material having substantially the same thermal expansion as the beam material. A plurality of wires 18 and 20 formed from an inorganic composition are positioned between opposed beams 10 and 14 and 12 and 16 so that wires 18 and 20 are uniformly spaced and form a grid. A plurality of hold-down straps 22, 23, 24, and 25 are formed of inorganic material such as ceramic or glass having substantially the same chemical and thermal properties as the beam material. Hold-down straps 22, 23, 24, and 25 overlie wires 18 and 20 extending over beams 10, 12, 14, and 16 and are bonded thereto with inorganic bonding material.

Abstract: A multicell x-ray detector of the gas-filled ionization type includes a metal body in which the front, rear, end and bottom walls together with a sealed cover define a channel in which there is a row of spaced apart electrode plates which define cells in which ionization events and resultant analog signals are produced in response to absorption of x-ray photons by the gas. The x-ray entrance window is formed in the front wall and extends over substantially the length of the channel. The window has a curved cross section which permits restriction of its internal stresses to tensile stresses so its thickness and, hence, its x-ray absorption is minimized. The edges of the electrode plates which are presented toward the window are curved to be concentric with and slightly spaced from the window.

Abstract: A gamma-ray compensated ionization chamber having cylindrical multiplex electrodes comprises first cylindrical multiplex electrodes and second cylindrical multiplex electrodes being arranged in reverse orders to that of the first cylindrical multiplex electrodes in the longitudinal direction of the cylindrical electrodes to prevent the deterioration of compensating characteristics caused by the variation of an external temperature and variation of gamma-ray spectrum.

Abstract: A cylindrical, multiple-anode proportional counter is provided for counting of low-energy photons (<60 keV) at count rates of greater than 10.sup.5 counts/sec. A gas-filled proportional counter cylinder forming an outer cathode is provided with a central coaxially disposed inner cathode and a plurality of anode wires disposed in a cylindrical array in coaxial alignment with and between the inner and outer cathodes to form a virtual cylindrical anode coaxial with the inner and outer cathodes. The virtual cylindrical anode configuration improves the electron drift velocity by providing a more uniform field strength throughout the counter gas volume, thus decreasing the electron collection time following the detection of an ionizing event. This avoids pulse pile-up and coincidence losses at these high count rates. Conventional RC position encoding detection circuitry may be employed to extract the spatial information from the counter anodes.

Abstract: A device for detecting and locating radiations, comprising at least one cathode brought to a first potential with respect to a reference potential in a sealed enclosure, a plurality of threadlike anodes insulated from one another and photosensitive means, said enclosure being provided with a port-hole transparent to the radiations involved, situated in register with said cathode and anodes, said device further comprising an insulating support with two faces, a portion of one of said two faces, situated in register with said port-hole, being coated with a layer of a conductive material forming a mesh network constituting said cathode, the extremities of said anodes being in the shape of a point and the axes of said anodes respectively coinciding with the axes of the meshes of said network, these points being recessed with respect to the insulating support face, coated with the network conductive meshes.

Abstract: An ionization chamber has separate drift and detection regions electrically isolated from each other by a fine wire grid. A relatively weak electric field can be maintained in the drift region when the grid and another electrode in the chamber are connected to a high voltage source. A much stronger electric field can be provided in the detection region by connecting wire electrodes therein to another high voltage source. The detection region can thus be operated in a proportional mode when a suitable gas is contained in the chamber. High resolution output pulse waveforms are provided across a resistor connected to the detection region anode, after ionizing radiation enters the drift region and ionize the gas.

Abstract: An improved cylindrical Geiger-Mueller tube with a life at least ten times reater than that heretofore obtainable includes a re-entrant insulator at each end of the tube to support the coaxial anode and to shield the tube ends from the Geiger discharge.

Abstract: A radiation detector of the gas-filled counter tube type which has a reduced count rate drift. An electrically conductive coating is applied to the interior insulating surfaces in proximity to the anode wire of a gas-filled counter tube structure having an axially disposed wire anode. The electrically conductive coating is maintained at the same electrical potential as the anode and accumulated charges in proximity to the anode are thereby eliminated. Alternately, the electrically conductive coating applied to the interior insulating surfaces in proximity to the anode may be maintained at the same electrical potential as the outer conducting cylinder in order to eliminate accumulated charges. The elimination of accumulated charges in proximity to the anode significantly reduces count rate drift and hence improves detector performance.

Abstract: A location- or positionally-sensitive proportional counter tube of high resolution having a trough-shaped cathode in a counting chamber. A resiliently elastic wire forming the anode extends longitudinally through the counting chamber. Suitable fastening arrangements engage the ends of the wire so as to mount the wire equidistantly from the side walls of the cathode trough and in electrical communication with the input resistor of a preamplifier. The counting chamber is an openable high-pressure chamber with inlet and outlet apertures for a pressurized counter tube gas.

Abstract: An improved x-ray or other ionizing radiation detector comprises an array of adjacent cells comprised of alternately disposed oppositely polarized electrodes and guard electrodes and insulators between them. Means are provided for maintaining uniform and accurate dimensions between electrodes and the overall length of the array.

Abstract: Xonics chambers can normally be used only with comparatively low electrode voltages in the Townsend-plateau region of the discharge where no charge carrier multiplication occurs. The sensitivity is then comparatively low. The sensitivity can be increased by increasing the electrode voltage, but this gives rise to a high electrode voltage for a reasonable charge carrier multiplication. According to the invention a gas is added whose ionization energy is smaller than the energy of the lowest metastable levels of the rare gas in the chamber. The charge carrier multiplication, and hence the sensitivity is thus improved without the electrode voltage being substantially increased. For example, when 0.2% by volume trimethylamine is added, an electrode voltage of 13 kV already suffices.

Abstract: A two-dimensional array of ionization chamber x-ray detector cells comprises a plurality of planar anode assemblies disposed equi-distant between parallel cathode plates in a gas of high atomic number. Each anode assembly comprises a plurality of conductive strips disposed on a thin dielectric sheet in a direction substantially parallel to the incident x-ray energy.

Abstract: An ionization chamber for use in determining the spatial distribution of x-ray photons in tomography systems comprises a plurality of substantially parallel, planar anodes separated by parallel, planar cathodes and enclosed in a gas of high atomic weight at a pressure from approximately 10 atmospheres to approximately 50 atmospheres. The cathode and anode structures comprise metals which are substantially opaque to x-ray radiation and thereby tend to reduce the resolution limiting effects of x-ray fluoresence in the gas.In another embodiment of the invention the anodes comprise parallel conductive bars disposed between two planar cathodes.Guard rings eliminate surface leakage currents between adjacent electrodes.