RU2268762C2 - Ionization x-ray electron-beam detector - Google Patents

Abstract

FIELD: medical equipment; X-ray diagnostics.

SUBSTANCE: device can be used in X-ray digital visualization systems. X-ray electron-beam detector has case, conversing member, collecting electrode, deflection system and electron searchlight. Conversing member has to be air-proof gas ionization chamber, which has drift electrode to be output window of the case. Electrodes of signal electrode system of air-proof ionization chamber are withdrawn onto surface of the chamber at the side of collecting electrode, deflection system and electron searchlight.

EFFECT: improved counting characteristics; higher quality of image; widened field of X-ray check.

1 dwg

Description

The proposed ionization x-ray electron beam detector is intended for use in x-ray digital imaging systems, in particular, in x-ray devices for medical diagnostics.

Known similar detectors used in x-ray installations for recording the distribution of the radiation flux density at the output of an object (see. X-ray technology: Handbook. In 2 books. Book 1. / Under the general editorship of V.V. Klyuev. - M .: Engineering, 1992. - P.159-160; patent 96108319 RU, IPC 6 H 01 J 31/58, published 10.27.98). These detectors contain a housing with an inlet window, a deflecting system, a converting element (photoconductive target or microchannel plate) located parallel to the plane of the inlet window, an electronic spotlight located in a vacuum environment from the side of the converting element not facing the inlet window. The x-ray beam through the input window enters the converting element and interacts with it. The potential relief obtained as a result of the interaction is read by a scanning electron beam formed by an electronic searchlight.

These detectors are characterized by a small x-ray control field, which is equal to the field of the converting element, significant inertia and low efficiency of registration of x-ray radiation, due to the properties of the converting element.

The closest in technical essence is the detector described in patent 96108319 RU, IPC 6 H 01 J 31/58, published 10.27.98, This detector contains a housing deflecting system, a converting element located parallel to the plane of the input window of the detector, a collector electrode and electronic searchlight located in a vacuum environment from the side of the converting element, not facing the input window. The converting element is a microchannel plate, which simultaneously performs the function of an amplifying element. The x-ray beam through the input window enters the converting element and interacts with it. The potential relief obtained as a result of interaction on the surface of the converting element from the side of the electronic searchlight is read by a scanning electron beam formed by the electronic searchlight.

The use of a microchannel plate as a transforming element complicates the design and manufacturing technology of the detector. The significant inertia of the microchannel plates does not allow an increase in the event counting rate, and the technological limitations on increasing the area and thickness of the microchannel plates do not allow an increase in the X-ray control field and the efficiency of X-ray detection.

The technical result of the present invention is to increase the speed of counting events, the field of x-ray control and the efficiency of registration of x-ray radiation. In addition, the design of the detector is simplified and technological difficulties in its manufacture are reduced.

The problem to which the claimed invention is directed is achieved by the fact that in a known x-ray detector comprising a housing, a conversion element, a collector electrode, a deflecting system and an electronic searchlight, the conversion element is a sealed gas ionization chamber, the drift electrode of which is also the input window of the housing and the electrodes of the system of signal electrodes of the sealed gas ionization chamber are brought to its surface from the side of the collector located in vacuum a ring-shaped electrode, the deflection system and the electron gun.

The drawing shows a schematic General view of an ionization x-ray electron beam detector.

The ionization x-ray electron-beam detector comprises a collector ring-shaped electrode 1, an electronic searchlight 2, a deflecting system 3, a housing 4, a conversion element, which is a sealed gas ionization chamber 5, containing a drift electrode 6, which is also an input window of the housing 4, and a signal electrode system 7, the electrodes of which are through conductors isolated from each other, discretely distributed over the surface and volume of the dielectric gas-tight plate, and brought to the surface of the sealed gas ionization chamber from the side of the collector ring-shaped electrode 1 and the electronic spotlight 2. The internal volume of the detector conversion element is filled with gas, and a high vacuum is maintained in the remaining volume of the detector. A positive potential is applied to the drift electrode 6 with respect to the cathode of the electronic spotlight 2, and a negative potential with respect to the cathode of the electronic spotlight 2 is applied to the collector ring-shaped electrode 1.

The device operates as follows. Gamma-rays of the radiation flux, passing through the input window of the housing 4, which is also the drift electrode 6 of the sealed gas ionization chamber 5, interact with the gas filling it. The electrons formed as a result of the interaction under the influence of an electric field created by the drift electrode 6 move toward this electrode, and the ions move toward the signal electrode system 7. When ions are deposited on the electrodes of the signal electrode system 7, the negative surface uniformly distributed charge partially existing on these electrodes is partially compensated after a preliminary cycle of scanning them with an electron beam, a charge relief is formed corresponding to the distribution of the radiation flux intensity from EKTA observation. The next time you scan the electrodes of the signal electrode system 7 with an electron beam, the latter will restore the original potential of these electrodes, as a result of which the signal taken from the collector ring-shaped electrode 1 will contain information about the original x-ray image.

At least, the ionization x-ray electron-beam detector can be single-axis.

The use of the conversion element, which is a sealed gas ionization chamber, instead of the conversion element, which is a microchannel plate, favorably distinguishes the proposed detector from the specified prototype, as this leads to an improvement in the counting characteristics of the detector, an increase in the field of x-ray control, and an increase in the detection efficiency of γ-quanta, which allows to reduce the dose received by the control object. In addition, the design and manufacturing technology of the detector is simplified and cheapened.

Claims (1)

X-ray electron beam detector, comprising a housing, a converting element, a collector electrode, a deflecting system, and an electronic searchlight, characterized in that the converting element is a sealed gas ionization chamber, the drift electrode of which is also the input window of the housing, and the electrodes of the signal electrode system are sealed gas the ionization chamber is brought to its surface from the side of the collector electrode, the deflecting system and the electronic searchlight.