Abstract:
PROBLEM TO BE SOLVED: To provide a substrate for electron amplification which can achieve a sufficient amplification factor while suppressing the occurrence of discharge in electron avalanche amplification, and to provide a method for manufacturing such a substrate for electron amplification.SOLUTION: A substrate 10 for electron amplification comprises an insulating glass base 11, conductive layers 12 and 13 formed on both of principal surfaces of the glass base 11, and through-holes 15 formed in a laminate 14 of the glass base 11 and the conductive layers 12 and 13. The substrate for electron amplification is arranged so that electric fields inside the through-holes 15 are formed by a potential difference between the conductive layers when a voltage is put between the surfaces of the conductive layer, thereby causing electron avalanche amplification inside the through-holes. In the substrate for electron amplification, insulating parts 20 are formed on at least one principal surface of the glass base 11 so that one ends surround openings of the through-holes 15 of the glass base 11, and the other ends are in contact with ends 12a, 13a of the conductive layers.
Abstract:
The invention relates to a gas avalanche detector for detecting and locating X-ray or gamma ray ionizing radiation in radiographic imaging, the detector comprising: a gas enclosure (10) provided with an admission window (FE) for admitting a beam (FX) of incident X-ray photons; an intermediate plane electrode (12) placed in said gas enclosure (10) between two end plane electrodes (11, 13) and held parallel to the two end plane electrodes (11, 13); the configuration of the end plane electrodes (11, 13) and of the intermediate plane electrode (12) forming an amplification space (20), the amplification space (20) also constituting a conversion space in which the incident X-ray photons (FX) are convertible into electrical charges, the electrical charges being made up of primary electrons and of corresponding ions; the intermediate electrode (12) being operable at an electrical potential relative to the electrical potentials of the end electrodes (11, 13) suitable for generating an electric field that causes the primary electrons to be multiplied by the avalanche phenomenon in the amplification space (20) in the vicinity of the intermediate electrode (12); one of the end electrodes (13) being configured as a collector electrode for picking up the electrical signals induced by the ions; and said admission window (FE) being placed level with the amplification space (20) between the intermediate plane electrode (12) and said collector electrode (13) to admit said photon beam between the intermediate plane electrode (12) and said collector electrode (13). The invention also relates to a radiographic imaging device including such a gas detector.
Abstract:
A presente invenção diz respeito a um contador gasoso de cintilação proporcional de alta pressão com grelhas múltiplas para radiação ionizante como raios X, raios gama, electrões e outros leptões carregados, partículas alfa e outras partículas carregadas dando informação sobre a energia dissipada no gás e o instante em que ocorreu a detecção, através de um impulso electrónico cuja amplitude é aproximadamente proporcional a esta energia. É essencialmente caracterizado por : - ter paredes exteriores (1) metálicas ao potencial da terra; - ser cheio à pressão de 1 a 100 atmosferas com um gás nobre puro e/ou continuamente purificado ou em mistura; - compreender: um fotocátodo de CsI reflectivo; e quatro grelhas: G1 (2), G2 (3), G3 (4) e G4 (5) feitas de uma malha fina com transmissão óptica elevada, não inferior a 80 %, definindo-se 5 regiões delimitadas pelas grelhas (2, 3, 4, 5) - sendo as tensões aplicadas ás diversas grelhas através dos passadores (9), as quais produzem campos eléctricos que não variam com o tempo nas diversas regiões do detector.
Abstract:
An ionising radiation detector comprising a chamber (1) filled with a noble gas and provided with an internal proportional counter (2) defining, between itself and an upper wall of the chamber, an absorption region (A) in which the radiation is ionised. The proportional counter comprises at least one anode (6) and at least one cathode (5) that are parallel to one another and separated by a layer of insulating material (7). Both the cathode and the layer of insulating material include at least one through-hole (8) in which a substantially uniform electric field is provided to form a region where electrons produced by the ionisation of the radiation are multiplied. Said detector is useful in medical imaging, biology, crystallography and particle physics.
Abstract:
The present invention concerns detectors for ionizing radiation (X-rays, gamma rays, electrons, protons, alpha particles, etc. as well as neutrons) of the gas proportional scintillation counter type. The preferred embodiment for X-ray detection consists in a detector, filled with very pure xenon at atmospheric pressure, with a 2.5 cm diameter radiation window (1), a grid with a spherical (2 cm radius) curvature (2) with its edges placed 0.8 cm away from a plane grid which is placed in contact with or close to a photomultiplier tube (4). This photomultiplier has uniform sensitivity in the 170 nm wavelength region. This detector presents an energy resolution of 8.0 % for 5.9 keV X-rays.
Abstract:
The counter is sensitive and compact and is intended to detect ionizing radiations, particularly for dosimetry and decontamination. The tube counter is of a flat construction and is composed of a few simple synthetic pans (1, 8, 9) as well as of a very elastic counter wire (2) which allows an easy production. The life duration of the tube counter filled with gas and carefully isolated is over 12 years. The tube counter may be adapted to a pocket apparatus. It is then associated with a high voltage generator with low parasitic voltages, provided with a pulse discriminator with parasitic voltage compensation.