RU2790441C1 - X-ray collimator manufacturing method - Google Patents

Abstract

FIELD: experimental physics and engineering instrumentation.

SUBSTANCE: invention relates to experimental physics and engineering instrumentation and concerns unwanted X-rays shielding in X-ray diffraction experiments for studying crystal structures of chemical compounds at high pressure and high temperature using high pressure chambers with diamond anvils equipped with a heating element. X-ray collimator is manufactured using a device consisting of two punches 1 and an insert 2 made of ceramic material placed between the punches, the profile of which follows the punches 1 profile. The insert 2 has a lenticular shape in the central part and a torus shape in the periphery, along the central axis of which holes are made in the punches 1 and in the insert 2 forming a single through hole, the diameter of which is equal to the outer diameter of metal capillary 5, which is placed in the through hole. The punches 1 are pressed to transfer the pressure created in the insert 2 to the capillary 5 to compress the capillary 5 and reduce its inner diameter in the compression zone. The capillary 5 is removed from the device and cut across the compression zone to obtain two identical collimators.

EFFECT: invention provides possibility to manufacture a collimator that allows diffraction experiments to be performed at high pressure and high temperature.

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Description

FIELD OF TECHNOLOGY

The invention relates to instrumentation in experimental physics and technology and concerns shielding of unwanted X-ray radiation when conducting X-ray diffraction experiments to study the crystal structures of chemical compounds at high pressure and high temperature using high-pressure chambers with diamond anvils equipped with a heating element.

BACKGROUND OF THE INVENTION

There are a large number of X-ray collimators for conducting experiments using diamond anvil high-pressure chambers, but they can all be divided into two categories: collimators consisting of one or more plates in which the necessary holes are made and collimators in the form of a tube with an internal hole .

Closest to the proposed method is the method of manufacturing the collimator presented in the document (US 4,602,377, published 22.07.1986 [1]). The collimator is a metal tube compressed by external high pressure with one hole, about 100 µm in diameter. The collimator is equipped with a lead tip, in which a hole is drilled. The method of manufacturing such a collimator is to drill a hole in a lead tip. The lead tip limits the use of the collimator in high temperature measurements.

X-ray diffraction makes it possible to determine the crystal structure and phase composition of the compound under study. It is known that many compounds have structural phase transitions at external high pressure and high temperature. Knowledge of the crystal structure and phase composition of a compound is often necessary to fully describe and understand its physical properties. Most X-ray diffraction experiments are currently carried out using synchrotron radiation. However, the shortage of time at synchrotron sources makes it important to carry out preliminary experiments in laboratories using standard X-ray diffractometers.

The technical problem solved by this invention is the creation of a method for manufacturing a collimator that will dock with a laboratory X-ray diffractometer and allow diffraction experiments to be carried out at high pressure and high temperature.

DISCLOSURE OF THE INVENTION

The technical problem is solved by a method for manufacturing an X-ray collimator, which consists in using a device containing two punches and an insert made of ceramic material placed between them, the profile of which repeats the profile of the punches, while the insert has a lentil shape in the central part, and a torus shape on the periphery , along the central axis of which holes are made in the punches and the liner, forming a single through hole, the diameter of which is equal to the outer diameter of the metal capillary, which is placed in the through hole, the punches are squeezed by a press to ensure the transfer of pressure created in the liner to the capillary, compression of the capillary and reduction its inner diameter in the compression zone, the capillary is removed from the device and cut across in the compression zone to obtain two identical collimators.

In addition, it is preferable to place the metal capillary in the through hole in such a way that the ends of the capillary are at a depth selected from the condition that they do not go beyond the hole when the capillary is compressed.

In this case, the press load is selected from the condition of providing the required reduced inner diameter of the collimator.

In addition, the height of the liner is chosen from the condition of providing the required length of the collimator hole with a reduced diameter.

The photon flux emitted from the X-ray tube of a laboratory diffractometer usually has a significant angular divergence and a large width. This angular divergence and large beam width must be eliminated in order to obtain a diffraction pattern only from the object under study, i.e., to prevent the emission of unwanted radiation that can scatter on the sample environment. One way to reduce the angular divergence and obtain a narrower parallel X-ray beam is to use a collimator. The collimator manufactured by the proposed method can be represented as a tube with a hole located between the X-ray source and the object under study. The magnitude of the angular divergence and the width of the X-ray beam obtained at the exit from the collimator are determined by the length and diameter of the collimator hole through which the X-rays pass. When using a collimator, the intensity of the photon flux decreases.

In devices with diamond anvils operating at high pressures and high temperatures, the dimensions of the objects under study are about 10 µm, the diameter of the hole in the gasket is 100 µm, and its thickness is about 10 µm. The proposed method makes it possible to manufacture a collimator that is compatible with high-pressure chambers with diamond anvils and allows measurements of X-ray diffraction patterns at high temperatures in the range of 20-650°C and high pressures using a standard laboratory X-ray diffractometer. The resulting X-ray diffraction patterns should provide an opportunity during processing to determine quantitatively the crystal structure and phase composition of the chemical compound under study.

The proposed method allows you to create a metal collimator for x-rays of a simplified design with a simplification of its manufacturing technology. The collimator makes it possible to obtain a parallel X-ray beam at the output with an angular divergence of up to 0.5° and a diameter of 30 µm. This collimator is tied to a laboratory X-ray diffractometer and a high-pressure chamber with diamond anvils and a high-temperature heater.

LIST OF DRAWINGS

Figure 1 shows a drawing of a device for the manufacture of a collimator in vertical section.

Figure 2 shows the area in which the collimator is crushed, in a vertical section, on an enlarged scale. The arrows show the direction of the forces acting in the insert.

Figure 3 shows the dependence of the diameter of the capillary outlet on the force of the press.

IMPLEMENTATION OF THE INVENTION

The collimator manufacturing device consists of two punches 1 pressed into the matrix block 3 and an insert 2 made of ceramic material: pyrophyllite, lithographic stone or pressed powder materials. In cross section, the insert 2 follows the profile of the end surfaces of the punches 1 facing each other. In the center of the punches 1 and the insert 2 there are through holes that form a single through hole. The insert 2 has a lentil shape in the center and a torus shape on the periphery.

The method of manufacturing an x-ray collimator is carried out as follows.

For the manufacture of the collimator, a metal capillary 5, for example, stainless steel, with an outer diameter of 4 mm and an inner diameter of 1 mm or less is used. This capillary 5 is placed in the through hole of the device in such a way that both of its ends are in the holes of the punches at a depth of at least 3 mm. The length of the capillary 5 is limited by the height of the punches 1 or the height of the pads 4, which can be placed above and below the punches 2. The outer diameter of the capillary 5 is equal to the diameter of the through hole.

The opening of the capillary 5 is pre-washed and cleaned of foreign particles. The capillary 5 is placed in the device in the holes of the punches 1 and the insert 2. The entire assembly is placed between the anvils of the press. By squeezing the assembly with a press, pressure is created in the lentil and torus of the liner 2, which deforms the capillary 5, reducing its inner diameter to the required value. Thus, it is possible to obtain the required diameter of the inner hole in the collimator by adjusting the load of the press.

The crushed capillary 5 is removed from the device and cut in the middle along the diameter in the compression area. In this way, two identical metal collimators are obtained, which can be attached to a laboratory X-ray diffractometer. The length of the collimator hole can be changed by changing the height of the ceramic insert 2, and the depth of the depressions on the surfaces of the punches 1. In this example, the height of the ceramic insert 2 was 8.2 mm. The length of the compressed part of the collimator was 3 mm.

Figure 3 shows how the inner diameter of the hole in the capillary 5 depends on the load applied to the press for a stainless steel capillary with an outer diameter of 4 mm and an inner hole of 1 mm.

The metal collimator obtained by the proposed method allows measurements of X-ray diffraction patterns at high temperatures in the range of 20 - 650°C and high pressures using a standard laboratory X-ray diffractometer.

Claims (4)

1. A method for manufacturing an x-ray collimator, which consists in using a device containing two punches and an insert made of ceramic material placed between them, the profile of which repeats the profile of the punches, while the insert has a lentil shape in the central part, and a torus shape on the periphery, along the central axis of which holes are made in the punch and the liner, forming a single through hole, the diameter of which is equal to the outer diameter of the metal capillary, which is placed in the through hole, the punches are squeezed by a press to ensure that the pressure created in the liner is transferred to the capillary, the capillary is compressed and its reduction inner diameter in the compression zone, the capillary is removed from the device and cut across in the compression zone to obtain two identical collimators. 2. The method according to claim 1, according to which the placement of the metal capillary in the hole is carried out with the placement of the ends of the capillary at a depth selected from the condition of not leaving the hole when the capillary is compressed. 3. The method according to claim 1, in which the press load is selected from the condition of providing the required reduced internal diameter of the collimator. 4. The method according to claim 1, according to which the height of the liner is selected from the condition of providing the required length of the collimator hole with a reduced diameter.

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