BG63177B1 - Screening device of x-ray or gamma-rays - Google Patents

Abstract

The device shall be used for the prevention of the release of X-ray of gamma-rays through an aperture in a screening channel, for example produced in irradiation with an electron beam. It includes a screening wall (2) forming a screened channel (3) with inlet and outlet hole. A source (1) generating X-ray or gamma-rays is fitted in wall (2). Multiple partition walls (7-1, 7-2 & 7-3) are fitted in channel (3) and are folded at least once between its inlet and outlet hole. 9 claims, 15 figures

Description

The invention relates to a screening device for x-ray or gamma-ray, in particular to screening devices for stopping x-ray or gamma-ray, which are generated, for example, by electron beam irradiation from the discharge of an opening through a shielded channel.

BACKGROUND OF THE INVENTION

A shielding device is generally used to screen X-ray or gamma ray radiation emitted from a radiation source, which encloses the source by screening walls of concrete, lead or iron. This reduces the intensity of the emitted X-rays or hammocks as they pass through the shielding walls and prevents them from leaking. However, where a substance or material is inserted or removed from the device, the inside of the shielding device is ventilated or access to the interior of the shielding device is required, which must have an opening. Therefore, the radiation source cannot be completely sealed.

For example, when the radiation source is part of a production line, the material to be irradiated is placed inside the shielding device and the treated articles are removed through an opening of the shielding device.

In another example, flue gases (flue gases) or wastewater are introduced inside the shielding device and are emitted from the source and discharged from the shielding device. Exhaust gases or waste water may be placed in a treatment vessel in the shielding device, irradiated with an electron beam and discharged. In particular, when electron beam is irradiated, when electrons collide with the bombarded gas or the like, secondary X-rays are generated, whereby the treatment vessel and the exhaust gases and waste water irradiated with the electron beam become a source of X-ray radiation.

In this case, it is necessary to use some design for screening x-rays or hammers so that they do not protrude through the opening.

Typically, X-ray or gamma-ray electromagnetic waves diminish when passing through a substance. As the distance to the source of radiation increases, they become weaker and their intensity decreases upon reflection from the surface of the substance. Therefore, in order to prevent the discharge of X-ray or gamma-ray through an opening, the channel is usually surrounded from the source to the opening by screening walls which are highly resistant to the transmission of X-ray or gamma-ray, increasing the length of the channel and folding it. In the present description, the channel enclosed by shielding walls with the above properties is referred to as a "shielded channel".

Figure 14A of the accompanying drawings shows a known shielding device having external shielding walls 22 forming a central chamber housing an X-ray or gamma ray source 21. One of the walls 22 has an opening 26 covered with a door 27. The opening 26 is mainly used to access the inside of the shielding device. Due to the need for the door to have virtually the same screening capability as that of the screening wall, to prevent the passage and release of X-ray or gamma-ray through it, it is not costly. Moreover, since in this type of screening device the door can only be opened when no X-ray or gamma-ray radiation is emitted, they cannot be used when a substance or material is imported or exported in the presence of X-ray or gamma ray radiation, and in case of ventilation of the device.

Figure 14B of the accompanying figures shows another known shielding device with a broken shielded channel surrounded by shielding walls. The device has external shielding walls 22 forming a chamber housing the source of X-ray or gamma ray 21. The shielding walls 22 form a curved shielded channel 23 that extends from the chamber to an opening 28 into one of the shielding walls 22 and closes with a door 29 Door 29 is standard and when no X-ray or hammer is generated, it can be opened, allowing access to the inside of the screening device through the shielding channel. In addition, the shielding device can also be ventilated when generating x-rays or hammers, leaving the door open.

The accompanying figure 15 shows another known shielding device with a broken shielded channel enclosed by shielding walls. The shielding channels 23A and 23B are formed by the outer shielding walls 22. The source of the X-ray or gamma ray 21 is placed in a central chamber with the shielding walls 22. The shielding channels 23A and 23B have at their opposite ends openings 24 and 25. respectively. or hamlets, substance or material are introduced into the inside of the shielding channel through shielded channel 23B.

When X-rays or hammocks pass through the screened channel, they diminish depending on the distance they have traveled, ie. the length of the screened channel, and the number of reflections they were subjected to. If the intensity of the X-ray or gamma-ray at the output of the screened channel is 1/100 of their intensity at its input, the attenuation rate is 100. The following empirical equation is used to calculate the degree of attenuation and to construct the screen channels:

I = I _o x L ² x R ^N (1), in which ² _O is the intensity of the X-ray or gamma-ray at points that are one unit distance from the center of the source, ² is their intensity at the outlet of the screened channel, L is the distance from the center of the source to the outlet, R is the degree of attenuation for one reflection of the rays, N is the number of reflections of the rays for the distance from the source to the outlet. Therefore, the degree of attenuation η for x-ray or gamma-ray at the opening is proportional to the square of the distance (L) from the source and to the N-degree of the number of reflections. Therefore, the decay rate η is derived from the following equation:

η -L ² x R ^N (2)

As shown in equation (2), the degree of attenuation depends on the distance and the number of reflections, which is why a screening device with a screened channel with an opening must have a larger volume and more material for screening X-ray or gamma ray than a device that is completely closed. This can be seen when comparing Figures 14A and 14B. When receiving x-rays or hammers in larger quantities and with more screening energy, more distance and more reflections are required, and therefore more volume and more material are needed. With a greater amount of substance or material introduced into or removed from the shielding device, the cross section of the shielded channel increases, resulting in an increase in the volume and quantity of the shielding material in the described examples of known devices. In particular, when treating exhaust gas that is irradiated in an electron beam screening device, the area of the shielded channel varies from several square meters to several tens of square meters. The increased volume imposes restrictions on the design of the device, and the large amount of shielding material increases its price and weight. This leads to an increase in the cost of the foundation on which the device is installed.

Publication JP 62-274300A discloses a radioactive radiation shielding channel comprising a cylindrical channel housing and a screw made of radioactive radiation shielding material and secured to the housing. The screw forms a folded passage for circulation of fluid flow inside the housing and has an axis extending along the axial axis of the housing. The screw is mounted by rotating in the housing and can also be rotated by a drive unit. In order to obtain satisfactory shielding of the X-ray or hammock, the inner surface of the cylindrical body and the outer periphery of the screw are connected by welding, so as to avoid the formation of a gap between the cylindrical channel and the outer periphery of the screw.

However, this method of avoiding gap formation is not effective because the contact line between the screw and the cylindrical channel is helix and it is very difficult to secure the screw to the cylindrical channel by welding without forming any gap.

This known solution cannot meet the requirements for use for an electron beam gas treatment system. In order to achieve satisfactory shielding in such a system, the known device must have very large dimensions, making it very difficult to make a very large screw and to attach it even more to the cylindrical housing.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a screening device for x-rays or hammers that has a substantially reduced volume and amount of material in the channel made therein.

The problem is solved according to a first aspect of the invention by creating a screening device for x-rays or hammers containing a shielding wall forming in it at least one screened channel with an inlet and outlet. The shielding wall allows the placement of an X-ray or gamma ray source, at which point it is located on the side of the inlet of the shielded channel. At least one inner panel or wall is located in at least a portion of the shielding channel. The inner plate or wall extends in a direction from the inlet to the outlet of the screened channel and is positioned such that the outlet is visually hidden from the inlet. Moreover, the inner plate or wall is bent at least once in the shielding channel and comprises a dividing plate or partition wall through which the shielding channel is divided into multiple passages.

It is appropriate that the partition plate or partition wall be in the form of a folded screen with at least one fold.

The shielding device may comprise at least one second dividing plate or wall located in at least a portion of the shielding channel to divide the passage into multiple secondary passages.

X-rays or hammocks can be generated from electron beam irradiation.

The electron beam may be designed to handle flue gas.

According to a second aspect of the invention, an X-ray or gamma-ray screening device is provided, comprising a screening wall forming at least one screened channel with an inlet and outlet opening, wherein an X-ray or gamma-ray source is placed in the wall, at which side it is located. the inlet of the shielded channel that is folded. The at least one dividing plate or partition wall is located in at least part of the screened channel, dividing it into multiple passages.

According to the second embodiment of the device, it is possible that x-rays or hammocks may also be generated by electron beam irradiation.

The electronic beam according to the second embodiment of the device may also be intended for flue gas treatment.

It is appropriate that the partition plate or partition wall be substantially at least one-twentieth and at least ten times the thickness of the half-attenuation layer of the material of the partition plate or partition wall.

Until now, it was considered that according to the screening device manufacturing procedure according to equation (1), the attenuation rate for X-ray or gamma ray does not change even if the shielded channel is separated, since the distance to the source and the number of reflections remain unchanged.

The invention has the following advantages. The attenuation rate for x-rays or hammers is increased by dividing the duct by a dividing plate or partition wall into multiple aisles. The degree of attenuation increases even if the separation plate is of a thickness that is not sufficient by itself to screen X-rays or hammocks. In this way a shielding effect is achieved with a reduced volume and amount of material used.

An explanation of the attached figures

In FIG. 1 shows a horizontal cross-section of an X-ray or gamma-ray screening device according to a first embodiment according to a first aspect of the invention;

In FIG. 2 is an enlarged axonometric view of the partition plates or partitions of a shielding device according to the first embodiment of the first aspect of the invention;

In FIG. 3 is a horizontal cross-sectional view of an X-ray or gamma-ray screening device according to a second embodiment of a first aspect of the invention;

In FIG. 4 is a graph showing the ratio of the degree of X-ray attenuation as a function of the ratio of thickness to the size of the half-attenuation layer;

In FIG. 5 is a graph showing the degree of X-ray attenuation depending on the number of partition blocks or partitions;

In FIG. 6 is a horizontal cross-section of a shielded channel used to explain Equations (2) and (3) below;

In FIG. 7 schematically illustrates an example of the use of a shielding device according to the invention in an electron beam gas treatment system;

In FIG. 8 is an axonometric view of a shielding device whose shielded channel is divided by partitions according to one embodiment of a second aspect of the invention.

In FIG. 9 is a horizontal cross-sectional view of an exemplary solution of a shielding device;

In FIG. 10 is a vertical sectional view of part of the exemplary solution of FIG. 9;

In FIG. lie is a graph showing the degree of X-ray attenuation as a function of the ratio of thickness to the size of the half-attenuation layer;

In FIG. 12 is a graph showing the X-ray attenuation rate depending on the value of the LI / S ratio;

In FIG. 13 is an enlarged axonometric view of the separation plates or partitions of the shielding device according to one embodiment, which is a combination of the first and second aspects of the invention.

In FIG. 14A shows a horizontal cross-section of a conventional screening device against X-ray or gamma ray;

In FIG. 14B shows a horizontal cross-section of another conventional screening device against X-ray or gamma ray; and

In FIG. 15 shows a horizontal cross-section of a third conventional screening device against X-ray or gamma ray.

Examples of carrying out the invention

Description of the solutions of the first aspect of the present invention with reference to FIG. from 1 to 6.

In FIG. 1 shows an X-ray or gamma ray screening device according to a first embodiment of the first aspect of the invention. The shielding device houses a radiation source 1, for example, a substance or material irradiated with an electron beam that emits secondary X-rays. The device has external shielding walls 2 forming in it a shielded channel 3. The shielding walls 2 contain blocks of partition plates or partitions 4-1 and 4-2. The shielding channel 3 has an X-ray inlet A at its end near the source 1 and an X-ray outlet B at its opposite end that is away from the source 1. Typically, the exit hole B closes with shield door 2d. The partition plates or partitions 4-1 and 4-2 are arranged so in the screened channel 3 that the inlet A is visually hidden from the outlet B.

In FIG. 2 is an enlarged view of each of the partition blocks or partitions 4-1 and 4-2. Each block consists of an upper panel 5, a lower panel 6 spaced below it, and a plurality of dividing plates or vertical partition walls 7-1, 7-2 and 7-3, which are located between the upper and lower panels 5 and 6 and are separated horizontally in a direction perpendicular to the longitudinal axis of the shielding channel 3 (Fig. 1). The shielding walls 2 touch the upper 5 and the lower panel 6 so that the X-rays through the contact portions of the shielding walls 2 with the upper 5 and the lower panel 6 are prevented. The dividing plate or partition wall 7-1, 7-2 or 7-3 consists of an inner slab or wall and divides the shielded channel 3 into multiple passages positioned laterally from one another, as shown in FIG. 2. Each of the partition plates or partitions 71, 7-2 and 7-3 is in the form of a folded screen and 5 is folded 90 ° with a central vertical fold line extending between its upper and lower ends, which are fixed respectively, to the upper 5 and the lower panel 6. The folds may be one or more, although 10 in FIG. 2 each of these dividing plates or partitions 7-1, 7-2 and 7-3 has a single fold 7f.

In FIG. 3 shows an X-ray or gamma ray screening device according to a second embodiment of the invention. In this embodiment, the shielding device has a spiral partition wall 8 disposed in the shielded channel 3 and extending between the inlet A and the outlet B. The radius wall 8 is wound around the center line C _L and extends longitudinally to the shielded channel. 3 in a constantly changing sequence of planes. The other elements of the shielding device of FIG. 3 25 are identical to those of FIGS. 1. These parts and components of the apparatus according to FIG. 3, which are structurally and functionally identical to those shown in FIG. 1 are denoted by the same numbers.

Description of an experiment with the shielding device shown in FIG. 1.

Two dividing plates or partitions of the block of FIG. 2 are inserted into the shielding device according to FIG. 1. A screening test for secondary X-rays obtained by electron beam irradiation. In this test, X-rays are emitted from irradiated material and have a maximum energy of 0.5 MeV and 0.8 MeV. Partition walls are of different materials, incl. iron and lead, and have different thicknesses, as shown in Table 1 below. The thickness-to-size ratio of the half-attenuation layer in Table 1 is defined as the ratio of the thicknesses of the partition walls to the half-attenuation layer shown in Table 2, and the half-attenuation layer is defined as the thickness of a sheet of material in which the intensity of X-ray fluxes through it, it is halved from its original value. The half-attenuation layer depends on the type of material and the maximum energy of the X-rays.

Table 1.

(Partition walls used in the experiment)

Partition wall material Partition wall thickness (mm) The ratio of thickness to the half-attenuation layer 0.5 MeV 0.8 MeV 1 0.10 0.08 Iron 3 0.29 0.23 10 0.95 0.76 20 1.91 1.52 10 2.49 1.42 Lead 20 4.97 2.83 40 9.95 5.67

Table 2. '(Semi-attenuation layer for X-rays)

Partition wall material (density) X-ray Energy (MeV) Half-attenuation layer (mm) Concrete 0.5 34.2 (2.4) 0.8 42.3 Iron 0.5 10.5 (7.86) 0.8 13.2 Lead 0.5 4.0 (11.34) 0.8 7.1

The total absorption coefficients of the materials used in the calculation of the half-attenuation layers are quoted by "Radiation" by Kyoritsu Shuppan and the material densities by "Rika Nenpyo" (Scientific Almanac) by Maruzen.

If the X-ray intensities at the input A and the output B of the shielded channel are assumed to be 1 _A and 1 _c , respectively, the attenuation rate η of the shielding device is defined as η - Ι _Α / Ι _Β . In FIG. 4 shows the degree of attenuation, depending on the ratio of thickness to the half-attenuation layer, measured for different materials and thicknesses of the partition plates and partitions, as well as different energies of the X-rays transmitted. In FIG. 4 confirms that the passed X-rays are suppressed if the partition walls have a thickness of 2.5 times (at a decay rate of 2 ² · ³ = 5.7) relative to the half-attenuation layer. It is also confirmed that even if the thickness of the partition walls is less than this value, a greater attenuation effect is obtained than in the absence of a partition wall. For example, even at a thickness-to-semi-attenuation ratio of 0.1, an attenuation degree of 50 to 100 is obtained, which means a significant attenuation effect. Increasing the thickness of the partition walls does not alter the damping effect, but diminishes the benefits of the shielding device in terms of the installation process or for cost-efficiency reasons. Therefore, the thickness of the partition walls may be practically at most several tens of times greater than the half-attenuation layer.

In another X-ray screening test, the number of partition blocks or partitions is increased (an additional partition or partition block is included, as shown by the dashed line in Fig. 1) without changing the partition wall thickness. The X-rays are generated from an X-ray source 1 with a maximum beam energy of 0.5 MeV, the lead barrier walls are 20 mm thick, measuring the attenuation rates for the first, second and third blocks of partition plates or partitions respectively. The results are shown in FIG. 5. Because the lead walls are 20 mm thick, in FIG. 5 shows the attenuation effect of only the reflected X-rays which are not affected by the X-rays transmitted. It is confirmed that the relationship between the number of blocks of partition plates or partitions and the degree of attenuation does not satisfy equation (1) but the following equation (3) derived according to the invention:

I _n = I _nl x [(a x L _n ² / S _n ) + β] ' ¹

According to the invention, if the intensities of X-rays from the radiation source 1 are denoted respectively by ² ,, ² 2 ,. ~, ² M in the respective folded portions Ρ ,, Ρ ^ ..., P _n of the shield passage 3 formed by the external shielding walls 2, as shown in FIG. 6, the intensity of ² n in the section Pn can be calculated from the intensity ² o1 in the previous section R _n, according to the above equation (3). In this equation S _n is the cross-sectional area of the screened channel from section P _n _, to section P _n , L _n is the distance from the folded section P to section P _p , and a and β are constants that depend on the shape of the section of the channel . In Equation (3), the term [a x L _n ² / S _n ) + β] denotes the attenuation rate for a single folded section. Equation (3) shows that the attenuation rate for a single folded section of the screened channel is proportional to the square of the distance from the point of reflection and is inversely proportional to the cross-sectional area of the channel. Therefore, the damping effect of the shielded channel can be increased by reducing its cross-sectional area, for example, by reducing the step (distance between) of the partition walls, as well as by increasing the number of reflections and distance.

The shielding device of FIG. 3 is also subjected to an X-ray screening test by electron beam irradiation. The spiral partition wall is made of iron and has a thickness of 10 mm. X-rays are generated from an X-ray source 1 and have a maximum energy of 0.5 MeV and 0.8 MeV. In this test, the attenuation rate η (= ² a / ² c) is 2000 at 0.5 MeV and 1500 at 0.8 MeV. Therefore, the shielding device according to FIG. 3 had the same damping effect as that of the device of FIG. 1.

Since the first X-ray screening device according to the first aspect of the invention has dividing plates or partitions located in the screened duct, the screening efficiency of the X-ray or screening device is increased, and the installation space and the cost of manufacturing the device can significantly to reduce.

In FIG. 7 shows an example in which the X-ray and gamma-ray shielding device of the invention is applied to an electron beam gas treatment system. The gas to be treated is fed through an inlet duct 31 into a treatment vessel where it is irradiated with an electron beam. The electrons are obtained from an electron beam generator and their energy ranges from 10 keV to several MeV. After irradiation, the gas is released through an outlet duct 34. Secondary X-rays whose maximum energy is equal to the energy of the electron beam are obtained by the impact of the electron beam with the bombed gas. Therefore, to prevent secondary X-rays from escaping, the shielding device is mounted so that the shielding walls 2 enclose the treatment vessel 32, the inlet duct 31, and the outlet duct 32. To prevent the discharge of secondary X-rays from the outlets of the inlet 31 and air ducts 34 are provided with a plurality of folds 7-1, 7-2 and 7-3, so that the inlet openings 31A and 32A for X-rays are visually hidden from the corresponding outlet openings 31B and 32B. Partition walls 7-1, 7-2 and 7-3 are made of a screen material of concrete, iron or lead, and their thickness ranges from a few tens to several tens of the layer for the damping of the screening material. The thickness of the partition wall is determined on the basis of the composition of the shielding material and the maximum energy of the x-rays generated. The electron generator 33 is of the self-shielding type, with the obtained X-rays being protected from being passed through the passing tip 37.

Description of another solution of the second aspect of the invention.

In FIG. 8 is an axonometric screening device for X-rays or hammers according to one embodiment of the second aspect of the invention. As can be seen from the figure, the shielding device includes a shielded channel with an inlet 11 and an outlet 12 for x-rays or hammers formed by external shielding walls 13. The shielded channel is bent at an angle of 90 °. Inlet 11 and outlet 12 are located at opposite ends thereof. The shielding channel of the shielding device also has dividing plates or partitions, which include vertical and horizontal dividing plates or partitions, combined to divide the shielded channel into multiple parallel passages 18, each of which has a rectangular section.

As indicated above, Equation (3) shows that the degree of attenuation in the fold of the shielded channel is proportional to the square of the distance to the point of reflection and is inversely proportional to the cross-sectional area of the shielded channel. It therefore follows that the damping effect of the shielded channel can be increased by reducing the cross-sectional area of the channel, as well as by increasing the number of reflections and the distance.

For example, if the partition wall 14 divides the shielded channel into nine identical parallel passages 18, as shown in FIG. 8, the attenuation effect for one fold is about 9 times greater than the attenuation effect that would be obtained without partition walls 14. Therefore, if the shielded channel has five folds and is divided into nine identical parallel passages, the effect the attenuation is about 60,000 (= 9 ^J ) times larger, although the volume of the shielded channel remains virtually unchanged. It has been experimentally found that the attenuation effect is obtained when the thickness of each of the partition walls 14 is at least one-twentieth (1/20) of the half-attenuation layer for X-rays or hammers passing through the partition walls 14. Therefore, partition walls 14 may be of very small thickness. This is another very important fact established according to the invention.

The following is an experiment conducted with a screening device according to the invention.

In FIG. 9 shows an X-ray shielding device with external shielding walls 13 forming a shielded channel in which an X-ray source 15 (an electron beam or material) is located. As can be seen from FIG. 10, in the area 16 of the shielded channel shown shaded in FIG. 9, a partition wall 14 is arranged parallel to the floor of the screened channel. In FIG. 9, the outlet is numbered 17. The shielded channel is 900 mm wide and 3000 mm high, and the partition wall 14 is positioned 1000 mm above the floor for dividing the shielded channel into two passages 18 at a 2: 1 cross-sectional area ratio. . X-rays are generated from an X-ray source 15 and have maximum energies of 0.5 MeV and 0.8 MeV. The partition wall 14 is made of various 5 materials, incl. aluminum, iron and lead, and is of different thicknesses, as shown in Table 3 below. The thickness-to-semi-attenuation ratio in Table 3 indicates the ratio of the thickness of the partition walls to the semi-attenuation layer given in Table 4.

Table 3, (Partition walls used in the experiment)

Partition wall material Partition wall thickness (mm) The ratio of thickness to the half-attenuation layer 0.5 MeV 0.8 MeV 5 0.16 0.13 Aluminum 10 0.33 0.27 1 0.10 0.08 Iron 3 0.29 0.23 10 0.95 0.76 20 1.91 1.52 10 2.49 1.42 Lead 20 4.97 2.83 40 9.95 5.67

Table 4.

(X-ray half-attenuation layer)

Material for Energy of Semi-attenuation layer partition wall (density) x-rays (MeV) (mm) Concrete 0.5 34.2 (2-4) 0.8 42.3 Aluminum 0.5 305 (2.69) 0.8 37.7 Iron 0.5 10.5 (7.86) 0.8 13.2 Lead 0.5 4.0 (11.34) 0.8 7.1

The total absorption coefficients of the materials used in calculating the half-attenuation layer are quoted by "Radiation" by Kyoritsu Shuppan and the material densities by "Rika Nanpyo" (Scientific Almanac) by Maruzen.

X-rays intensities I, / 1 ₃ (see Fig. 9) at the inlet and outlet of the shielding duct were measured and the attenuation rates η ( ^w 1 ₍ / 1 ₃ ) were calculated to compare the attenuation effects of the shielding a channel according to the invention and a screening channel without a partition wall.

In FIG. 11 shows the degrees of X-ray attenuation depending on the ratio of thickness to the half-attenuation layer. Point (a) indicates the attenuation rate for the half-attenuation layer for the screening duct (with a cross-sectional area of 2.7 m ² ) without a partition wall, o represents the attenuation rates of the X-rays per half-attenuation layer for the upper passage (with a cross-sectional area of 1.8 m ² ) on the screened channel with a partition wall and Δ - the degrees of attenuation for the half-attenuation layer for the lower transition (cross-sectional area 0.9 w ² ) in the screened mud with a partition wall. An analysis of what is presented in FIG. 11 shows that the attenuation rate is greater with a smaller cross-sectional area, with the same distance from the X-ray source and with the same number of reflections, and also that the attenuation effect increases when the shielded channel is separated by partition wall.

In FIG. 12 show the attenuation rates (1, / 1 ₃ ) for a single reflection in the shielded channel according to FIG. 9. Equation (3) described above can be deduced from the data shown in FIG. 12. From FIG. 11 confirms that the attenuation effect does not change even when the thickness of the partition wall is reduced to one-tenth of the half-attenuation layer (1 mm thick iron partition wall with a maximum X-ray energy of 0.5 MeV). By reducing the thickness of the partition wall 0.08 times from the half-attenuation layer (a 1-mm-thick partition wall with a maximum X-ray energy of 0.8 MeV), the attenuation effect is slightly reduced, but such an effect is still obtained by increasing the the attenuation efficiency without changing the shape of the shielded channel. Further increases in the thickness of the partition wall do not alter the damping effect, but diminish the advantages of the shielding device in terms of the installation process and for cost-efficiency reasons. Therefore, the thickness of the partition wall can be practically no more than ten times the size of the half-attenuation layer.

According to the second aspect of the invention, since the screening device for x-ray or hammock has a shielded channel separated by dividing plates or partitions, the screening efficiency of the device for x-ray or hammock is increased, and the device needs relatively small space for installation and structural its value may be relatively low.

Description of a solution of a combination of the first and second aspects of the invention according to FIG. 13. This combination provides a significant damping effect for X-rays or hammocks.

In FIG. 13 is an enlarged block of dividing plates or partitions

4-1 (or 4-2). This figure corresponds to FIG. 2. The block 4-1 (or 4-2) shown in FIG. 13 is identical to block 4-1 (or 4-2) shown in FIG. 2, except that it includes a plurality of dividing plates or partitions 9 extending between the partition walls 7-1 and 7-3 vertically in a longitudinal direction in the longitudinal direction of the shielded channel 3 (see Fig. 1). The partition plate or partition wall 9 represents a second partition wall. As shown in FIG. 13, the shielded channel 3 (see FIG. 1) is separated by a divider plate or a partition wall 7-1, 7-2, or 7-3 into multiple passages arranged side by side, and the upper passage is separated by a divider plate or a partition wall 9 on a plurality of secondary passageways, each having a rectangular section, arranged vertically side by side. As a result, the X-ray attenuation rate can be further increased.

Various changes and modifications can be made to the invention without departing from the scope of the appended claims.

Industrial applicability

The invention is suitable for a screening device in which an X-ray or gamma-ray source cannot be completely isolated due to the need for the substance or material to be imported and removed from the device when X-ray or gamma-ray radiation is emitted from the source. The invention is particularly applicable to flue gas treatment systems in which x-rays are generated by electron beam strikes with the treated gas and the treated gas and by-product must be drawn through an opening in the shielded channel.

Claims

Claims (9)

1. An X-ray or gamma-ray shielding device comprising a shielding wall (2) forming at least one shielding channel (3) therein, including at least an inlet (A) and an outlet (B), the shielding wall (2) being adapted for accommodating a source of X-ray or gamma ray (1) and located at the side of the inlet (A) of the shielding channel (3), and at least one inner plate or wall (7-1, 7-2, 7-3), located in at least part of the screening channel (3), with the inner plate or wall (7-1, 7-2, 7-3) oriented in the direction from the inlet (A) to the outlet the opening (B) of the shielding duct (3), wherein the inner plate or wall (7-1, 7-2, 7-3) is inserted into the shielding duct (3) such that the outlet opening (B) is visually hidden from the inlet (A), characterized in that the inner plate or wall (7-1, 7-2, 7-3) is bent at least once in the shielding duct (3) and comprises a dividing plate or partition wall (9,14), through which the shielding channel (3) is divided into multiple passages (18). A screening device according to claim 1, characterized in that the dividing plate or partition wall (9, 14) is in the form of a folded screen with at least one fold (7f). Shielding device according to claim 1, characterized in that it comprises at least one other dividing plate or wall (9, 14) located in at least part of the shielding channel (34) for dividing the passage into multiple secondary passages (18). Shielding device according to any one of claims 1 to 3, characterized in that the X-ray or gamma ray are generated by electron beam irradiation. Shielding device according to claim 4, characterized in that the electron beam is designed to process flue gases. 6. An X-ray or gamma-ray shielding device comprising a shielding wall (13) forming at least one shielding channel therein, including at least an incoming wall, 5 a door (11) and an outlet (12), the shielding wall (13) being adapted to accommodate an X-ray or gamma ray source and is located on the side of the inlet (11) of the shielding channel, characterized in that the shielding channel is bent in shape and at least one dividing plate or partition wall (9, 14) is disposed in at least a portion of the shielding channel to divide the shielding channel into multiple passages (18). Shielding device according to claim 6, characterized in that x-rays or hammers are generated by electron beam irradiation. Screening device according to claim 7, characterized in that the electron beam is designed for flue gas treatment. Shielding device according to claim 6, characterized in that the partition plate or partition wall (9, 14) has a thickness that is substantially at least one-twentieth of the size of the half-attenuation layer of the material of the partition or partition wall (9 , 14). Attachment: 15 figures