SU1639272A1 - Combined detector for roentgen tomography - Google Patents

Abstract

The invention relates to the detection of x-ray radiation used in scanning systems, computer tomographs. The purpose of the shadow is to improve the image resolution in contrast by decreasing the dependence of the amplitude of the detector signal on the spectral composition of the radiation while maintaining the high effect of the X-ray diffraction and low afterglow. The goal is achieved by using a ZnSe-based scintillator as a sensitive element of the detector. In this case, neurovalent activators Te or Mg at a concentration of 3 mol.% Or donor A1 or acceptor Cu at a concentration of 2–0 2 mol L were used as quality activators. Due to the high efficiency of X-ray transformations with a low energy resolution of the detector, an improvement in the image quality of tomograms has been achieved as compared with the use of traditional detectors based on body and halogenoid scintillators. 1 hp f-ly, 2 tab. C 9

Description

This invention relates to the detection of ionizing radiation and can be used in X-ray tomographs.

The aim of the invention is to improve the image resolution in contrast by reducing the dependence of the amplitude of the detector signal on the spectral composition of the radiation while maintaining a high X-ray conversion efficiency and low afterglow.

According to this solution, a scintillator — activated zinc selenide — was used as the sensitive element of the detector.

As activators, Te or Mg activators were used at a concentration of 3 mol.%, Either donor - A1 or acceptor - Cu at a concentration of 2-10 2 mol.%.

 Despite their high light output, transparency and kinetic characteristics, these scintillators are not spectrometric, i.e. practically do not possess energy resolution.

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This property of scintillators from Zelennd zinc, which prevents the use of spectrometry, significantly improves the resolution of the contrast, when used as detectors for X-ray computed tomography.

The drawing shows a combined detector for X-ray computed tomography.

The detector contains a scintillator 1, an optical connection 2, a photodiode 3. The scintillator 1 is connected via a optical connection 2 to a photodiode 3. On-J5 is connected by means of a material that is transparent to the radiation of the scintillator 1 and has a refractive index, intermediate between the refractive indices of scintillator 1 and photodiode 3 materials (in particular, epoxy resin, silicone glue, etc.).

A reflective coating is applied to the entire surface of the scintillator 1, with the exception of the 25 plane connected to the photodiode 3.

The detector works as follows.

X-ray radiation is absorbed by the scintillator 1 JQ and is converted by it into a snake. The light signal through the optical connection 2 enters the photodiode 3, in which it is converted into an electrical one. Electric ,,. The CHI and the L of photodiode 3 are amplified by electronic units and analyzed by computer (not shown in the drawing).

In tab. Figure 1 shows the main parameters of scintillators used in schmographin in combination with a photodiode.

In tab. 2 shows similar parameters of the proposed scintillators made of activated zinc selenide 45 depending on the type of activator and its concentration.

From the comparison of the data table. 1 and 2, we can draw the following conclusions.

The energy resolution of the proposed scintilla tori is much lower (4–7) times than in the known ones, and the contrast resolution in scintillators made of activated zinc selenide is much higher (2–5) times.

For all listed in table. 2, the types of activators of scits on the skeleton zinc skeleton differ little in their temporal characteristics, in the maximum of the emission spectrum, radio luminescence, energy resolution, and have high resolution and contrast.

The light yield of the activated zinc selenide depends significantly on the type and concentration of the activator and is within the suggested activator concentrations at a level that allows practical use of this material in X-ray computational tomography.

The increase in the concentration of the activators introduced into the crystals above mentioned in the table. 2 values (example No. 6 for all types of activators), leads to violation of single phase in crystals, cracking, reduced transparency and, as a consequence, a sharp decrease in light output.

The introduction of isovalent activators in a concentration of less than 3-10 2 mol.% And non-isovalent activators in a concentration of less than 3-1C emol. % significantly reduces the light output of scintillators, making them unsuitable for use.

Optimal concentrations of activators, taking into account the magnitude of the light output, are for Te and Mg - 3 3 mol.% For A1 and Cu - 2.%.

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Thus, due to the combination of properties, the proposed detector has an improved spatial resolution of the image in tomographic devices.

Claims (2)

1. A combined detector for X-ray computational tomography, comprising a sensitive element, a scintillator with a reflective coating, optically coupled to a photodiode, characterized in that, in order to improve image resolution in contrast by decreasing the dependence of the amplitude of the detector signal on the spectral composition of the radiation while maintaining high efficiency of re-genetransformation and low afterglow; activated zinc selenide is used as a sensitive element. 2. Detector on. 1, characterized in that as an 51639272 The element used is from a range of 3 mol.% for Te and Mg, Mg, A1, Cu in a concentration of 3--10 z-2-10 mol.% for A1, Cu. i i That blitz one one 0.5-5 0.5-1.5 0.005 0.2 0.01 0.5-5 415 550 480 540 9 12 12 390 18 730 15 one one one Those Mg A1 Si S-2 S-2 S-1 one 3 3.5 -2 - i ten 340 10 one 3 3.5 yuz h "then 10 10 10 10 2- 3- -g. dz Yy gz 10 (G3 g R 3. 5. 10 2 FROM ten . thirty 70 150 100 30 5 thirty 35 80 50 20 20 thirty 75 50 20 15 ten 40 65 40 10 5 0.05 0.05 0.05 0.05 0.05 0.05 0.05-0.1 m || 0.1 It 480 540 12 12 390 18 730 15 one one one Spreadsheets 640 640 640 640 640 640 30-650 00-62C 50 50- 50 50 50 50 None h m Missing 5 5 5 5 5 5 3-5 p AND "|| P 5-10 40-650 m P eleven ( .AND II Missing and 2-5 t . 1 11