Environment-adaptive concrete gamma-ray shielding capability measurement device and method

Abstract

An environment-adaptive concrete gamma-ray shielding capability measurement device and method. The measurement device comprises an irradiation test chamber and a plurality of concrete test blocks, wherein a shielding door is provided on the tail end of a channel (3) of a spiral structure in the irradiation test chamber, and a cavity is provided on the head end of the channel (3); a first cavity adapted for having a radiation source (5) placed therein is formed in the lower portion of the cavity, and a second cavity (4) adapted for receiving a sample to be tested is formed in the upper portion of the cavity; a three-dimensional laser scanner (7) is provided above the second cavity (4); and a plurality of radiation alarm devices (6) are provided on a wall of the channel (3). The size of the concrete test blocks matches the size of the second cavity (4), and each concrete test block is formed by concrete hemispheres (1, 2) which have exactly the same shape and have been subjected to micro-void filling using a neat cement paste, hemispheroidal cavities for receiving a silver dichromate dosimeter bottle (8) being provided in the middle of the concrete hemispheres (1, 2). By means of the present device, the concrete gamma-ray shielding capability measurement method based on an irradiation system avoids the problem of a calculated shielding capacity value being large due to the escape of scattered electrons when gamma rays and substances undergo a Compton effect.

Description

A device and method for measuring the gamma ray shielding ability of environmental concrete Technical Field

[0001] The present invention belongs to the technical field of building construction, and in particular relates to an environmental concrete gamma ray shielding capability measuring device and method. Background Art

[0002] Nuclear radiation generally refers to alpha, beta, gamma, X-rays, and neutrons. Of these, gamma rays and neutrons have the strongest penetrating power and, therefore, are the primary targets of protection in radiation protection. When studying the penetration of gamma rays into concrete, researchers often use a linear penetration test method. This method connects a radiation source, a concrete specimen, and a receiver. The shielding performance of the concrete is calculated by measuring the difference between the gamma ray intensity before and after shielding. However, this method fails to account for the scattered photons caused by the Compton effect between gamma rays and concrete. Photons scatter from the concrete, causing the receiver reading to be understated and the calculated shielding capability to be overstated.

[0003] Therefore, there is an urgent need to provide a convenient, safe, and environmentally friendly concrete gamma-ray shielding capability measuring device and a method for use.

[0004] Summary of the Invention

[0005] The present invention provides an environmental concrete gamma ray shielding ability measuring device and method, which avoids the problem of excessively large shielding ability calculation values ​​caused by scattered electrons escaping when gamma rays and matter produce Compton effect.

[0006] In order to solve the above technical problems, the present invention includes the following technical solutions:

[0007] An environmental concrete gamma-ray shielding capability test device comprises an irradiation test chamber and multiple groups of concrete test blocks. The irradiation test chamber is a spiral structure cast from barite concrete. A shielding door is provided at the end of the channel of the spiral structure of the irradiation test chamber, and a cavity is provided at the head end of the channel of the spiral structure of the irradiation test chamber. The lower portion of the cavity forms a first cavity for accommodating a radiation source, and the upper portion of the cavity forms a second cavity for holding a sample to be tested. A three-dimensional laser scanner is provided above the second cavity. Multiple radiation alarm devices are provided on the channel wall of the spiral structure of the irradiation test chamber. The dimensions of the concrete test blocks match the dimensions of the second cavity. The concrete test blocks are formed by concrete hemispheres of identical shape with micro-voids sealed by cement slurry. A hemispherical cavity is provided in the middle of the concrete hemispheres. The radius of the concrete hemisphere is 10 cm larger than the radius of the hemispherical cavity. The hemispherical cavity is used to hold a silver dichromate dosimeter bottle.

[0008] Furthermore, the concrete test block is installed in the second cavity through a support, and the support is fixed to the bottom end of the concrete hemisphere located at the lower end.

[0009] Furthermore, the support is a cylindrical support, and four of the cylindrical supports are evenly distributed at the bottom end of the concrete hemisphere located at the lower end.

[0010] Furthermore, it also includes a lightweight bracket, which is matched with the hemispherical cavity, and the silver dichromate dosimeter bottle is placed above the lightweight bracket.

[0011] The present invention also provides an environmental concrete gamma ray shielding capability determination method, and provides the aforementioned environmental concrete gamma ray shielding capability determination device for standby use. The method comprises:

[0012] Step S1, selecting a batch of 6 pairs of concrete hemispheres of different types;

[0013] Step S2: placing six silver dichromate dosimeter bottles into the hemispherical cavity of the concrete hemisphere at the lower end in sequence;

[0014] Step S3: placing six groups of concrete test blocks in the second cavity of the spiral structure of the irradiation test chamber, and using a three-dimensional laser scanner to locate the six silver dichromate dosimeter bottles respectively. Based on the three-dimensional coordinate values, the six silver dichromate dosimeter bottles are placed at the same three-dimensional coordinate point and fixed with lightweight brackets so that the six silver dichromate dosimeter bottles are fully exposed to the radiation field;

[0015] Step S4: closing the shielding door at the end of the spiral-structured passage of the irradiation test chamber, and starting the irradiation device to irradiate for 1 hour. After the irradiation is completed, the irradiation device is turned off. When the radiation value measured by the radiation alarm device reaches a normal level, the shielding door at the end of the spiral-structured passage of the irradiation test chamber is opened, and the six groups of concrete test blocks are removed, as well as the silver dichromate dosimeter bottles in the hemispherical cavities of the six groups of concrete test blocks.

[0016] Step S5: using an ultraviolet-visible spectrophotometer to measure the radiation dose absorbed by each silver dichromate dosimeter and record it as D0;

[0017] Step S6: Select three other batches of different types of concrete hemispheres with the same mix ratio, place a silver dichromate dosimeter bottle into the hemisphere cavity of each concrete hemisphere at the lower end, cover the concrete hemisphere at the upper end, and seal the micro-voids with cement paste to form six groups of concrete test blocks;

[0018] Step S7, repeating steps S3 to S4;

[0019] Step S8: using an ultraviolet-visible spectrophotometer to measure the radiation dose absorbed by each silver dichromate dosimeter, and recording them as D0, D1, D2, and D3 respectively;

[0020] Step S9: Calculate the photon attenuation effect using Formula 1:

[0021] Where μ is the linear attenuation coefficient, in cm -1 .

[0022] Furthermore, the cement paste mix ratio (kg / m 3 )as follows:

[0023] Furthermore, the cement is PO 52.5 cement, the fly ash is Class II fly ash, the mineral powder is S95 mineral powder, and the silica fume has a specific surface area of ​​18 to 25 m 2 / g, water reduction rate of admixture>15%.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] The present invention provides an environmental concrete gamma-ray shielding capability measurement device, comprising an irradiation test chamber, a spiral structure cast from barite concrete, a shielding door at the end of the spiral structure's passageway, and a cavity at the beginning of the spiral structure's passageway. The lower portion of the cavity forms a first cavity for accommodating a radiation source, and the upper portion of the cavity forms a second cavity for holding a sample to be tested. A three-dimensional laser scanner is located above the second cavity. Multiple radiation alarm devices are located on the walls of the spiral structure's passageway. The dimensions of the concrete test block match those of the second cavity. The concrete test block is formed from a concrete hemisphere of identical shape, micro-voids sealed with cement paste. A hemispherical cavity is located in the middle of the concrete hemisphere, with a radius 10 cm larger than the radius of the hemispherical cavity. The hemispherical cavity is used to hold a silver dichromate dosimeter bottle. The present invention utilizes a method for measuring the gamma-ray shielding capability of concrete based on an irradiation system, thereby avoiding the problem of overstated shielding capability calculations caused by scattered electrons escaping when gamma rays undergo the Compton effect with matter. In other words, the environmental gamma-ray shielding capacity test method of the present invention avoids the drawback of linear penetration testing methods, where photons scatter and escape from surrounding planes, causing large measurement errors. Consequently, the test results of the present invention are more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic structural diagram of a concrete hemisphere located at the lower end of an environmental concrete gamma ray shielding capability measuring device according to an embodiment of the present invention;

[0027] FIG2 is a schematic structural diagram of a concrete hemisphere located at the upper end of an environmental concrete gamma ray shielding capability measuring device according to an embodiment of the present invention;

[0028] FIG3 is a schematic structural diagram of an environmental concrete gamma-ray shielding capability measuring device according to an embodiment of the present invention;

[0029] FIG4 is a schematic diagram showing the placement of a silver dichromate dosimeter bottle in an environmental concrete gamma ray shielding capability determination device according to an embodiment of the present invention;

[0030] FIG5 is a schematic diagram showing the placement of a lightweight support in an environmental concrete gamma ray shielding capability testing device according to an embodiment of the present invention;

[0031] 6 is a schematic diagram illustrating the connection between the upper and lower concrete hemispheres of a concrete test block in an environmental concrete gamma ray shielding capability testing device according to an embodiment of the present invention;

[0032] FIG7 is a schematic diagram of a device for measuring the linear penetrating concrete gamma ray shielding capability.

[0033] In the picture:

[0034] 1—concrete hemisphere at the lower end; 2—concrete hemisphere at the upper end; 3—spiral-structured channel of the irradiation test chamber; 4—second cavity; 5—radiation source; 6—radiation alarm device; 7—3D laser scanner; 8—silver dichromate dosimeter bottle; 9—lightweight bracket; 10—cement paste; 11—cylindrical support, 12—radiation source, 13—dosemeter, 14—concrete sample, 15—γ-ray receiver, 16—lead plate. DETAILED DESCRIPTION

[0035] The following is a further detailed description of an environmental concrete gamma ray shielding capability measurement device and method provided by the present invention, in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in illustrating the purpose of the embodiments of the present invention. For ease of description, the "upper" and "lower" described below are consistent with the upper and lower directions of the accompanying drawings, but this does not constitute a limitation of the technical solution of the present invention.

[0036] Example 1

[0037] 1 to 7 , the structural composition of the environmental concrete gamma-ray shielding capability measuring device of the present invention will be described in detail.

[0038] Continuing with Figures 1 to 6, an environmental concrete gamma-ray shielding capability test device includes an irradiation chamber and multiple sets of concrete test blocks. The irradiation chamber is a spiral structure cast from barite concrete. A shielding door is located at the end of the spiral channel 3, and a cavity is located at the beginning of the spiral channel 3. The lower portion of the cavity forms a first cavity for accommodating a radiation source 5, and the upper portion of the cavity forms a second cavity 4 for holding the sample to be tested. A three-dimensional laser scanner 7 is located above the second cavity 4. Multiple radiation alarm devices 6 are installed on the walls of the spiral channel 3. The dimensions of the concrete test blocks match those of the second cavity 4. The concrete test blocks are formed from two identical concrete hemispheres sealed with cement paste 10 to create micro-voids. A hemispherical cavity is located in the middle of each concrete hemisphere. The radius of the concrete hemisphere is 10 cm larger than the radius of the hemispherical cavity. The hemispherical cavity is used to hold a silver dichromate dosimeter bottle 8. Specifically, a concrete hemisphere with a radius of 12 cm can be selected. In this case, the radius of the hemisphere cavity is 2 cm. The two concrete hemispheres with exactly the same shape are concrete hemisphere 1 at the lower end and concrete hemisphere 2 at the upper end.

[0039] In this embodiment, more preferably, in order to ensure the installation stability of the spherical concrete test block, the concrete test block is installed in the second cavity through a support, and the support is fixed to the concrete hemisphere 1 located at the lower end.

[0040] Specifically, the support is a cylindrical support 11, with four cylindrical supports 11 evenly distributed at the bottom end of the concrete hemisphere 1. The cylindrical supports 11 can be 1 cm in diameter and 3 cm in height. Of course, the support can also be a bayonet or groove, which is not limited here.

[0041] In this embodiment, more preferably, a lightweight bracket 9 is further included, and the lightweight bracket 9 cooperates with the hemispherical cavity. The silver dichromate dosimeter bottle 8 is placed above the lightweight bracket 9 to achieve stable placement of the silver dichromate dosimeter bottle 8.

[0042] Continuing to refer to FIG. 1 to FIG. 6 , the present invention further provides a method for determining the gamma ray shielding capability of environmental concrete, and provides the aforementioned device for determining the gamma ray shielding capability of environmental concrete for standby use. The method comprises:

[0043] Step S1, selecting a batch of 6 pairs of concrete hemispheres of different types;

[0044] Step S2: six silver dichromate dosimeter bottles 8 are sequentially placed into the hemispherical cavity of the concrete hemisphere 1 at the lower end; silver dichromate dosimeters are placed in the silver dichromate dosimeter bottles 8.

[0045] Step S3: placing six groups of concrete test blocks in the second cavity 4 of the spiral structure of the irradiation test chamber, and using a three-dimensional laser scanner 7 to respectively locate six silver dichromate dosimeter bottles 8, recording the three-dimensional coordinates (x1, y1, z1), (x2, y2, z2), (x3, y3, z3), (x4, y4, z4), (x5, y5, z5), and (x6, y6, z6); and placing the six silver dichromate dosimeter bottles 8 at the same three-dimensional coordinate point based on the three-dimensional coordinate values, and fixing them with a lightweight bracket 9 so that the six silver dichromate dosimeter bottles 8 are fully exposed to the radiation field;

[0046] Step S4: Close the shielding door at the end of the spiral channel 3 of the irradiation test chamber, start the irradiation device, and perform irradiation for 1 hour. After the irradiation is completed, turn off the irradiation device. When the radiation value measured by the radiation alarm device 6 reaches the normal level, open the shielding door at the end of the spiral channel 3 of the irradiation test chamber, remove the six groups of concrete test blocks, and remove the silver dichromate dosimeter bottles 8 from the hemispherical cavities of the six groups of concrete test blocks.

[0047] Step S5: using an ultraviolet-visible spectrophotometer to measure the radiation dose absorbed by each silver dichromate dosimeter and record it as D0;

[0048] Step S6: Select three other batches of different types of concrete hemispheres with the same mix ratio, place the silver dichromate dosimeter bottle 8 into the hemisphere cavity of the concrete hemisphere at the lower end, cover the concrete hemisphere at the upper end, and seal the micro-voids with cement paste to form six groups of concrete test blocks;

[0049] Step S7, repeating steps S3 to S4;

[0050] Step S8: using an ultraviolet-visible spectrophotometer to measure the radiation dose absorbed by each silver dichromate dosimeter, and recording them as D0, D1, D2, and D3 respectively;

[0051] Step S9: Calculate the photon attenuation effect using Formula 1:

[0052] Where μ is the linear attenuation coefficient, in cm -1 .

[0053] In this embodiment, more preferably, the cement paste mix ratio (kg / m 3 )as follows:

[0054] In this embodiment, more preferably, the cement is PO 52.5 cement, the fly ash is Class II fly ash, the mineral powder is S95 mineral powder, and the silica fume has a specific surface area of ​​18 to 25 m 2 / g, water reduction rate of admixture>15%.

[0055] In this embodiment, more preferably, the barite concrete mix ratio (kg / m 3 )as follows:

[0056] In this embodiment, more preferably, the aforementioned gamma ray shielding ability determination method and the commonly used linear penetration test method are used for determination, and ordinary concrete and barite concrete are selected for comparative tests, and the results are analyzed.

[0057] 7 , a commonly used linear penetration test method is shown, wherein a radiation emission source 12 , a dosimeter 13 , a concrete sample 14 , a gamma ray receiver 15 , and a lead plate 16 are provided.

[0058] Ordinary concrete mix ratio (kg / m 3 )as follows:

[0059] The radiation dose absorbed by each silver dichromate dosimeter of the ordinary concrete was measured by UV-visible spectrophotometer, and the values ​​were D0, D1, D2, and D3, respectively, which were 3.74, 1.07, 1.03, and 1.11, respectively. Substituting them into the photon attenuation effect formula,

[0060] Therefore, the environmental concrete gamma ray shielding ability determination method of the present invention is used to determine the linear attenuation coefficient μ of ordinary concrete. 新 is 0.125cm -1 .

[0061] For ordinary concrete measured by the commonly used linear penetration test method, the radiation dose absorbed by each silver dichromate dosimeter is D0=3.70, D1=0.81, D2=0.88, and D3=0.76. Substituting them into the photon attenuation effect formula,

[0062] Therefore, the linear attenuation coefficient of ordinary concrete is determined by the commonly used linear penetration test method. 旧 is 0.151cm -1 .

[0063] In this embodiment, more preferably, the cementitious material of the barite concrete includes PO 52.5 cement, the fly ash is S95 blast furnace slag powder, and the aggregate includes a density of 4.0g / m 3 The density of barite and barite sand; crushed stone and river sand are both 2.5kg / m 3The admixture includes TX600 high-performance water-reducing agent, which has a solid content of 19.3% and a water reduction rate of more than 18%.

[0064] The radiation dose absorbed by each silver dichromate dosimeter of the barite concrete was measured by UV-visible spectrophotometer, and the results were D0 = 3.92, D1 = 0.95, D2 = 0.94, and D3 = 0.95. Substituting them into the photon attenuation effect formula,

[0065] Therefore, the linear attenuation coefficient μ of the barite concrete is determined by the environmental concrete gamma ray shielding ability determination method of the present invention. 新 is 0.142cm -1 .

[0066] The radiation dose absorbed by each silver dichromate dosimeter of the barite concrete was measured by UV-visible spectrophotometer, and the results were D0 = 3.95, D1 = 0.67, D2 = 0.71, and D3 = 0.61. Substituting them into the photon attenuation effect formula,

[0067] Therefore, the linear attenuation coefficient μ of barite concrete was determined by the commonly used linear penetration test method. 旧 is 0.178cm -1 .

[0068] It can be seen that the method of the present invention avoids the defect of the linear penetration test method in which photons are scattered and escape from the surrounding planes, causing large measurement errors. The measurement results of the present invention are more accurate.

[0069] The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. The above embodiments only express several embodiments of the present invention, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several variations and improvements can be made, which all fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent of the present invention shall be based on the attached claims.

Claims

1. An environmental concrete gamma ray shielding capability measuring device, characterized in that: The invention comprises an irradiation test room and a plurality of groups of concrete test blocks. The irradiation test room is a spiral structure cast by barite concrete. A shielding door is arranged at the end of a channel of the spiral structure of the irradiation test room. A cavity is arranged at the head end of a channel of the spiral structure of the irradiation test room. The lower part of the cavity forms a first cavity for placing a radiation source. The upper part of the cavity forms a second cavity for holding a sample to be detected. A three-dimensional laser scanner is arranged above the second cavity. A plurality of radiation alarm devices are arranged on a channel wall of the spiral structure of the irradiation test room. The size of the concrete test block matches the size of the second cavity. The concrete test block is formed by micro-gaps plugged by cement paste with concrete hemispheres of exactly the same shape. A hemisphere cavity is arranged in the middle of the concrete hemisphere. The radius of the concrete hemisphere is 10 cm larger than the radius of the hemisphere cavity. The hemisphere cavity is used to hold a silver dichromate dosimeter bottle.

2. The environmental concrete gamma ray shielding capability measuring device according to claim 1, characterized in that: The concrete test block is installed in the second cavity through a support, and the support is fixed to the bottom end of the concrete hemisphere located at the lower end.

3. The environmental concrete gamma ray shielding capability measuring device according to claim 2, characterized in that: The support is a cylindrical support, and four cylindrical supports are evenly distributed at the bottom end of the concrete hemisphere located at the lower end.

4. The environmental concrete gamma ray shielding capability measuring device according to claim 3, characterized in that: It also includes a lightweight bracket, which is matched with the hemispherical cavity, and the silver dichromate dosimeter bottle is placed above the lightweight bracket.

5. A method for determining the environmental gamma ray shielding capability of concrete, characterized in that: An environmental concrete gamma ray shielding capability measuring device according to any one of claims 1 to 4 is provided for standby use, the method comprising: Step S1, selecting a batch of 6 pairs of concrete hemispheres of different types; Step S2: Place six silver dichromate dosimeter bottles into the concrete hemisphere at the lower end. In the hemispherical cavity of the body; Step S3, placing 6 groups of concrete test blocks in the second cavity of the spiral structure of the irradiation test room, and using a three-dimensional laser scanner to respectively locate the six silver dichromate dosimeter bottles, and according to the three-dimensional coordinate values, placing the six silver dichromate dosimeter bottles at the same three-dimensional coordinate point, and fixing them with lightweight brackets, so that the six silver dichromate dosimeter bottles are completely exposed to the radiation field; Step S4, close the shielding door at the end of the spiral structure channel of the irradiation test room, start the irradiation device, and perform irradiation for 1 hour. After the irradiation is completed, turn off the irradiation device, and when the radiation value measured by the radiation alarm device reaches a normal level, open the shielding door at the end of the spiral structure channel of the irradiation test room, take out 6 groups of concrete test blocks, and take out the silver dichromate dosimeter bottles in the hemispherical cavities of the 6 groups of concrete test blocks; Step S5, using an ultraviolet-visible spectrophotometer to measure the radiation dose absorbed by each silver dichromate dosimeter and record it as D0; Step S6, select three other batches of different types of concrete hemispheres with the same proportion, and place the silver dichromate dosimeter bottles in the hemisphere cavities of the concrete hemispheres at the lower end in turn; and cover the concrete hemispheres at the upper end, and use cement slurry to seal the micro-gaps to form 6 Group concrete test blocks; Step S7, repeating steps S3 to S4; Step S8, using an ultraviolet-visible spectrophotometer to measure the radiation dose absorbed by each silver dichromate dosimeter, and recording them as D0, D1, D2 and D3 respectively; Step S9: Calculate the photon attenuation effect using Formula 1: Where μ is the linear attenuation coefficient, in cm -1 .

6. The method according to claim 5, characterized in that The cement paste mix ratio (kg / m 3 )as follows:

7. The method according to claim 6, characterized in that The cement is PO 52.5 cement, the fly ash is Class II fly ash, the mineral powder is S95 mineral powder, and the specific surface area of ​​silica fume is 18-25m 2 / g, water reduction rate of admixture>15%.

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