31 results about "Gas electron multiplier" patented technology

The present invention provides a digital imaging photodetector with a gas electron multiplier. The digital imaging photodetector comprises a gas electron multiplier detector. The gas electron multiplier detector includes a photoelectric converter for converting incident light into photoelectrons or Compton electrons; a gas electron multiplier (GEM) for receiving the photoelectrons or Compton electrons from the photoelectric converter and multiplying them; and a readout unit for receiving an electrical signal indicating a position where an electron cloud multiplied in the gas electron multiplier arrives on an anode, recognizing coordinates of the electron cloud based on the received signal, and outputting the coordinates of the electron cloud. According to the digital imaging photodetector of the present invention, real-time imaging of image information can be achieved by multiplying photoelectrons or Compton electrons, which are discharged due to a photoelectric effect or a Compton effect induced by visible rays, ultraviolet rays or X-rays, using the gas electron multiplier.

[Problems to be Solved] It is an object of the present invention to provide a novel radiographic image detector which can detect radiation, such as hard X-rays or γ-rays, with high sensitivity and which is excellent in position resolution and count rate characteristic.

[Means to Solve the Problems] A radiographic image detector comprises a combination of a scintillator, such as a lanthanum fluoride crystal containing neodymium, for converting incident radiation into ultraviolet rays; and a gas multiplication ultraviolet image detector for converting ultraviolet rays into electrons, amplifying such electrons by use of a gas electron avalanche phenomenon, and detecting the electrons. The radiographic image detector is characterized in that the gas multiplication ultraviolet image detector is basically constituted by a photoelectric conversion substance, such as cesium iodide or cesium telluride, for converting ultraviolet rays into electrons; a gas electron multiplier for amplifying electrons by use of the gas electron avalanche phenomenon; and a pixel electrode having an amplification function and a detection function.

The invention provides a microchannel plate type fast neutron position gas detector and a detection method thereof, and relates to the field of nuclear technology applications. The detector comprises a gas chamber with an intake hole and an exhaust hole, a drift cathode, a microchannel structure plate, a gas electron multiplier, a high voltage dividing circuit, a read out PCB and a working gas. The drift cathode is arranged in the gas chamber with the intake hole and the exhaust hole. The microchannel structure plate is arranged below the drift cathode. The gas electron multiplier is arranged below the microchannel structure plate. The read out PCB is arranged below the gas electron multiplier. The working gas fills the whole chamber and a microchannel in the microchannel structure plate. The microchannel plate type fast neutron position gas detector provided by the invention can normally work at a high counting rate, and can be used for large part non-destructive detection and container scanning security check.

A readout board for use in a micropattern gas detector comprises a plurality of detector pads arranged into a plurality of consecutive layers that are separated by dielectric spacer material. An electron cloud hitting the front side of the readout board will induce a charge on one of the detector pads of the uppermost layer. By capacitive coupling, the signal will propagate downwards through the consecutive layers until it reaches the bottom layer, from which the charges are read out and analyzed. The position of the impact can be determined by comparing the charges that have spread to neighboring readout pads. Since only the bottommost layer of the readout pads needs to be connected to readout electronics, incident particles can be localized at high precision despite the relatively large size of the readout pads in the bottom layer. The invention is effective both in a gas electron multiplier (GEM) and in a MicroMegas detector.

The invention is a manufacturing method for gas electron multiplier polymers film mesh applied to the X ray detection. The invention uses 308nm norm molecular laser to irradiate the polyimide (PI) coated with red copper film at the two surfaces, the micro-aperture mesh are formed on the PI film by using the effect of the micro-aperture array mask board attached on the PI film. The mesh with any size can be acquired with X-Y scanning platform. The invention produces the gas electron multiplier polymer film mesh can be acquired by using 308nm norm molecular laser poring method. It is simple and effective.

The invention provides an ionization absorption spectrum detection device based on a multi-channel electron multiplier; the ionization absorption spectrum detection device includes an ionization chamber for ionizing gas, a golden net, the multi-channel electron multiplier, a voltage increasing and signal acquisition circuit, and a signal processing system; the golden net is arranged in the ionization chamber and arranged for collecting ions generated from ionization in the ionization chamber; the multi-channel electron multiplier is arranged in the ionization chamber, has the position opposite to the position of the golden net so as to form an electric field between the multi-channel electron multiplier and the golden net, receives the ions collected by the golden net through the action of the electric field and outputs a corresponding ion signal; the voltage increasing and signal acquisition circuit is connected to the multi-channel electron multiplier and arranged for providing voltage for the multi-channel electron multiplier and acquiring and outputting the ion signal; the signal processing system is arranged for receiving the ion signal and acquiring a corresponding ionization absorption spectrum according to the ion signal. The ionization absorption spectrum detection device can improve the accuracy degree of measurement beam line energy resolution ratio and reduce the influence of gas collision broadening on a final result.

A dosimeter based on a gas electron multiplier and method of use thereof for measurement of doses of therapeutic radiation to which a tissue-phantom is exposed. Subsequent to the in-phantom measurement and verification of radiation beam delivery, radiation can be effectively delivered to a human target organ, based on the verification of radiation quantities to which the phantom was exposed. Use of a gas electron multiplier-based dosimeter facilitates precise and accurate verification of the radiation dose within a phantom by taking measurements in real time, with no need for subsequent film processing.

An array gas electron multiplier (GEM) digital imaging radiation detector and a control method thereof are disclosed. The array gas electron multiplier (GEM) digital imaging radiation detector includes an array GEM detector. The array GEM detector includes: an ionized electron generation unit for generating ionized electrons in internal filling gas by incident X-rays or gamma rays or by incident charged particles; a gas electron multiplication unit for multiplying the ionized electrons of the ionized electron generation unit in filling gas inside hole of a gas electron multiplier (GEM), through electron avalanche effect, using the GEM, to form electron clouds; a readout for detecting and outputting coordinates of the electron clouds as the readout receives positions through electrical signals, in which the positions of the electron clouds, being multiplied and formed in the gas electron multiplication unit, reach output electrodes. Therefore, the present invention can multiply ionized electrons of internal filling gas as a gas electron multiplier (GEM) generates an electron avalanche effect in the hole thereof, in which the ionized electrons are generated as a photo-electron effect or a Compton effect is induced by high energy incident light, such as X-rays or gamma rays, or which are directly generated by incident charged particles, and can convert image information of the inside or outside of an target object into images of two-dimensions, in real time, such that the detector can be properly used as a security search apparatus in a harbor or an airport, or can be adapted as a core part of industrial nondestructive testing apparatus.

A detector for radiation, particularly high energy electromagnetic radiation is provided. The detector includes a converting section including a cathode for converting the radiation incident on the converting section in electrons by the photoelectric effect. The detector further includes a gas electron multiplier for generating an electron avalanche from electrons which are generated by the converting section and enter the gas electron multiplier, the gas electron multiplier including a first electrode, a dielectric layer and a second electrode, the first electrode being disposed at a first side of the dielectric layer adjacent to the converting section and the second electrode being disposed at a second side of the dielectric layer opposite to the first side. The gas electron multiplier includes a number of holes filled with gas, the holes extending through the first electrode, the dielectric layer and the second electrode.

A multilayer thick gas electron multiplier for suppressing a charging effect and a preparation method thereof are provided. The multilayer thick gas electron multiplier comprises a substrate unit anda diamond-like carbon-based film, wherein a plurality of arrayed through holes are disposed on the substrate unit; isolating rings are disposed in the circumferential direction of the through holes and are located on the upper and lower surfaces of the substrate unit; the diamond-like carbon-based film is formed in a surface of the substrate unit not covered by the isolating rings. The multilayerthick gas electron multiplier is improved in working stability, greatly increased in gain, and expanded in application range.

The invention discloses a sliding type self-tensioning method for installing and manufacturing a large-area gas electron multiplier (GEM) detector. The sliding type self-tensioning method comprises a GEM film fixing method and a method for applying a tension force on the GEM film. Two kinds of pad strips are used for fixing a drift electrode and four edges of a GEM film. The first kind of pad strips are arranged in the middle between the drift electrode and the GEM film edge; and the second kind of pad strips are arranged at positions, approaching corner, of the two ends of the drift electrode and the GEM film edge. Sliding blocks are fixed at the outer sides of the two kinds of pad strips; and screw holes are formed in the outer sides of the sliding blocks. Clamp grooves are formed in the main frame; the parts, with the screw holes, of the outer sides of the sliding blocks are clamped into the clamp grooves for positioning; and through holes are formed in the walls of the clamp grooves; and bolts pass through the through holes and are screwed into the screw holes for tensioning. According to the invention, the method has all advantages of the self-tensioning method but problems that exist when the GEM detectors with the levels above nanometer level are manufactured are solved. Therefore, the provided method has the high design flexibility and can be used for manufacturing large-area GEM detectors with all shapes and various dimensions.

An apparatus for detecting X-rays comprises a scintillator which emits a plurality of photoelectrons upon being impacted by an X-ray photon. The photoelectrons are amplified in a gas electron multiplier and the resultant photoelectrons are accumulated on a two dimensional array of charge collection electrodes. Electrical signals are produced which indicate the quantity of photoelectrons which strike each charge collection electrode. A processor determines a location of the X-ray photon strike by analyzing the spatial distribution of the photoelectrons accumulated by the array of charge collection electrodes. The intensity of the X-ray photon is determined from the number of accumulated photoelectrons.

A gas electron multiplier comprises a read-out positive anode plate (1) and a micro grid electrode structure (2), the micro grid electrode structure (2) is formed by cascading of n layers of micro grid electrodes (21) through a support structure (3), and the support structure (3) is fixed on the read-out positive anode plate (1), wherein micropores of the micro grid electrode (21) of an upper layer are staggered with the micropores of the micro grid electrode (21) of a lower layer, a gas avalanche amplification region is formed among the micro grid electrodes (21), and n is an integer greaterthan 3. The gas electron multiplier can improve total gain of the of electron multiplication and simultaneously reduce ion feedback rate. A photoelectric detector can be manufactured based on the gaselectron multiplier, and thus, problems, such as increase of cost and decline of counting rate, caused by resistive electrodes are avoided, gain stability is improved, moreover, a problem that a photocathode material sensitive to visible light is liable to be damaged by ion feedback is solved.

The invention discloses a circuit board partition block seamless laser processing method for a thick gas electron multiplier. The method comprises steps that 1), rough shape cutting is carried out according to design requirements to acquire an original plate; 2) a positioning hole is drilled in the original plate acquired through rough shape cutting in the step 1); 3) the original plate after treatment in the step 1) is covered with a dry film layer, and the dry film layer is exposed and developed; 4) the original plate after treatment in step 3) is subjected to copper window etching, and a dry film is removed; 5) laser drilling on the original plate after treatment in the step 4) is carried out; 6), an outer layer line is prepared on the original plate after treatment in the step 5), andacid etching is carried out; and 7), gold plating on the surface of the original plate after treatment in the step 6) is carried out. The method is advantaged in that product quality is improved, compatibility is improved, and production difficulty is reduced.

The invention discloses a multilayer net boron-coating thick GEM (Gas Electron Multiplier) neutron detector, which comprises a drifting electrode and a reading electrode, wherein the drifting electrode and the reading electrode are arranged in parallel side by side; a neutron transformation body is arranged between the drifting electrode and the reading electrode in parallel; the neutron transformation body comprises at least one layer of metal net; the surface of the metal net is coated with boron; the surface, which faces the reading electrode, of the drifting electrode is coated with the boron; a thick gas GEM is arranged between the neutron transformation body and the drifting electrode in parallel. According to the multilayer net boron-coating thick GEM neutron detector disclosed by the invention, a transformation area and a multiplication area are separated, the transformation area can be based on a plurality of boron-coating metal substrates, neutron detection efficiency can begreatly improved, no expensive boron 10 materials are wasted, the thick GSM of the multiplication area is durable, and gain can be easily controlled.