CN213337403U

CN213337403U - Material classification system

Info

Publication number: CN213337403U
Application number: CN202021658149.6U
Authority: CN
Inventors: 王骞; 王新奎; 郑振吉
Original assignee: Xuchang Ruishi Electronic Technology Co ltd
Current assignee: Xuchang Ruishi Electronic Technology Co ltd
Priority date: 2020-08-11
Filing date: 2020-08-11
Publication date: 2021-06-01
Anticipated expiration: 2030-08-11

Abstract

The utility model provides a material classification system belongs to the material classification field. The classification system comprises a collimator, a ray generation device and a detector array, wherein the detector array comprises a common detector and a ray energy spectrum measuring detector, the ray energy spectrum measuring detector is arranged in a place which is not shielded by a measured object in the detector array, the ray energy spectrum measuring detector comprises a detector panel, a plurality of typical material blocks are covered on the detector panel, and the typical material blocks are used for measuring ray energy spectrum. The classification system has the advantages that: firstly, a typical material block and a detector panel are integrated into a whole to form a special detector which can be used for measuring a ray energy spectrum, so that the measurement of the ray energy spectrum is more convenient; secondly, the ray energy spectrum can be measured in real time in the process of material classification by installing the ray energy spectrum measuring detector in the detector array, the coincidence of the ray energy spectrum and the working state of the ray generating device is ensured, and further the material classification precision is improved.

Description

Material classification system

Technical Field

The utility model relates to a material classification system belongs to material classification technical field.

Background

Based on the different absorption degrees of the substances to the rays with different energies, the inspection system based on the X-ray perspective imaging technology can identify the equivalent atomic number of the substances and further classify the substances into organic substances or light substances, mixtures or light metals, inorganic substances or metals, heavy metals and the like. However, the energy of the radiation passing through the object may vary with the state of the accelerator, the state of the light path, and other factors, and such variation may affect the material classification accuracy of the inspection system, for example, there may be differences in the classification results of the same material at different times.

Most of the existing energy calibration devices scan several specific substances before or after the start of scanning or at specific time points, so as to calibrate parameters in a substance classification model and keep the accuracy of the substance classification model. The main disadvantages of this type of calibration device are that it must be calibrated without a scanning task, it cannot be calibrated in real time, it can only be estimated roughly by empirical and statistical models, or from other sensors, for real-time variations of the ray energy during the scanning.

At present, there is also an energy calibration device capable of implementing real-time calibration, for example, patent document No. CN101614683B discloses a real-time calibration apparatus, which is configured to install a real-time calibration device (i.e., an energy calibration device) on a side of an original material classification system close to an accelerator to adjust material classification parameters in real time, so as to adapt to the current accelerator state, wherein the real-time calibration apparatus has two implementation manners, one is to include only a calibration material, one is to include both the calibration material and a calibration detector, and no matter which implementation manner needs to install a corresponding device on one side of the accelerator, so the energy calibration apparatus can implement real-time calibration, but has a complex structure.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a material classification system for solve the comparatively complicated problem of structure of current material classification system.

In order to achieve the above object, the utility model provides a material classification system, including collimater, ray generating device and detector array, include ordinary detector and ray energy spectrum survey detector among the detector array, the ray energy spectrum surveys the place that the detector setting is not sheltered from by the testee in the detector array, ray energy spectrum survey detector includes the detector panel, the detector panel coats and is stamped a plurality of typical material pieces, typical material piece is used for surveing the ray energy spectrum.

The substance classification system has the advantages that: firstly, a typical material block and a detector panel are integrated into a whole to form a special detector which can be used for measuring a ray energy spectrum, so that the measurement of the ray energy spectrum is more convenient; secondly, through installing ray energy spectrum survey detector in the detector array just can survey ray energy spectrum in real time at the categorised in-process of material, guarantee that ray energy spectrum and ray generating device's operating condition accord with, and then improve the categorised precision of material, simple structure, convenient to use.

Further, in order to improve the accuracy of energy spectrum measurement and further improve the accuracy of substance classification, in the substance classification system, the typical substance blocks covered on the detector panel are made of different materials, and the typical substance blocks are made of one of aluminum, graphite, steel, lead and tungsten.

Further, in order to improve the accuracy of the energy spectrum measurement and thus the accuracy of the substance classification, the thickness of each typical substance piece covered on the detector panel is different in the above-described substance classification system.

Further, in the above substance classification system, the typical substance blocks covered on the detector panel are arranged in a step shape.

Further, in the above-described substance classification system, the radiation spectrometry detector is disposed at an edge position of the detector array.

Drawings

FIG. 1 is a schematic diagram of a prior art material classification system;

FIG. 2 is a schematic diagram of a material sorting system according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a radiation spectrometry detector in an embodiment of the material classification system of the present invention;

in the figure, 1 is a ray generating device, 2 is a calibration material, 3 is a collimator, 4 is a detector array, 5 is a measured object, 6 is a ray spectrometry detector, 7 is a common detector, 8 is a typical material block, 9 is an X-ray detector array, and 10 is a circuit board.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

Substance classification system embodiment:

a material classifying system in the prior art is shown in fig. 1, in which a calibration material 2 is disposed between a radiation generating device 1 (e.g. an accelerator) and a collimator 3, and when performing material classification, the ray generating device 1 is used for generating an X-ray beam (with an arrow thick solid line in the figure), the collimator 3 is used for restraining the X-ray beam generated by the ray generating device 1 within a range which can be detected by the detector array 4, one part of the X-ray beam reaches the detector array 4 through the calibration material 2, one part of the X-ray beam reaches the detector array 4 through the object to be detected 5, the detector array 4 simultaneously receives the X-ray which passes through the calibration material 2 and the X-ray which passes through the object to be detected 5, two sets of transmission data are generated, when the material classification is carried out, the classification parameters of the substance classification system are corrected by using the perspective data corresponding to the calibration material 2, so that the accuracy of the classification result of the object to be measured 5 is improved.

The substance classifying system of the present embodiment is shown in fig. 2, and the substance classifying system is different from the substance classifying system shown in fig. 1 in that: the ray spectrum measuring device has the advantages that calibration materials do not need to be independently arranged between the ray generating device 1 and the collimator 3, the ray spectrum measuring detector 6 is only arranged at a place (generally located at the edge position of the detector array 4) which is not shielded by the measured object 5 in the detector array 4, the ray spectrum can be measured in real time in the material classification process, the ray spectrum is ensured to be consistent with the working state of the ray generating device 1, the material classification precision is further improved, the structure is simple, and the use is convenient. The principle is as follows: because the detector array 4 simultaneously comprises two detectors, namely the ray energy spectrum measuring detector 6 and the common detector 7, when the substance classification is carried out, the common detector 7 is used for measuring the X-ray which penetrates through the object to be detected 5 to serve as substance classification data, the ray energy spectrum measuring detector 6 is used for measuring the energy spectrum of the X-ray generated by the ray generating device 1 in real time, and then the substance classification data is corrected by means of the obtained X-ray energy spectrum to improve the accuracy of the substance classification.

As shown in fig. 3, the radiation spectrometry detector 6 includes a detector panel (i.e., an X-ray detector array 9 and a circuit board 10), the detector panel is covered with 4 typical material blocks 8 (the number of the typical material blocks can be adjusted according to actual conditions), and the typical material blocks are different in thickness and are arranged in a step shape. When the ray energy spectrum measurement is carried out, X-rays generated by the ray generating device penetrate through each typical material block to reach the detector panel, the detector panel converts the X-rays penetrating through each typical material block into perspective data corresponding to each typical material block, and the energy spectrum of the X-rays generated by the ray generating device can be obtained according to the obtained perspective data corresponding to each typical material block.

Wherein, the material and the thickness of each typical material piece that covers on the detector panel all can set up according to actual need, for example: the typical material blocks are the same in material and the same in thickness, and at the moment, the typical material blocks are equivalent to only one type of typical material blocks with uniform thickness covered on the detector panel; or the typical material blocks are made of the same material and have different thicknesses, and the typical material blocks with various thicknesses are covered on the detector panel; or the typical material blocks are different in material and same in thickness, and the panel of the detector is covered with various typical material blocks with the same thickness; or the typical material blocks are different in material and thickness, which is equivalent to that the detector panel is covered with a plurality of typical material blocks with different thicknesses; of course, the material portions or the thickness portions of the typical material pieces may be the same. The more the material types and the thickness gradients of the typical material blocks covered on the detector panel, the higher the accuracy of the ray energy spectrum measurement.

Wherein, the selection basis of typical material block material is: the material of the typical material block is selected according to the energy level. For example, in the 3-6MeV system, graphite-aluminum is the most difficult to distinguish, while lead-iron is relatively easy to distinguish, and therefore aluminum is chosen as the material for the typical mass. Of course, graphite, steel, lead, tungsten, etc. may be used as the material of the typical mass. The thickness of a typical mass is determined by: generally, more than 4 step thicknesses are provided in a range of 10% -75% of the absorbed ray dose; in general, the higher the equivalent atomic number of a typical material, the thinner the thickness of the typical mass can be made.

The principle that the radiation spectrum measuring detector can realize the radiation spectrum measurement is described in detail below by taking the example that the typical material blocks covered on the detector panel are the same in material but different in thickness.

X-rays follow the following absorption law when passing through an object:

I_D(E)＝I₀(E)*exp(-u(E,Z)*D)

in the formula i₀(E) Is the intensity of X-rays with energy E in the X-ray energy spectrum; u (E, Z) is an absorption coefficient of a substance having an atomic number Z (hereinafter referred to as substance Z) to X-rays having an energy E, and the value is constant; d is the thickness of the substance Z, I_D(E) Is the intensity remaining after an X-ray of energy E in the X-ray spectrum has passed through a substance Z of thickness D.

Therefore, the X-ray with energy E in the X-ray energy spectrum obtained by the ray energy spectrum measuring detector respectively passes through the thickness of 0 and the thickness of D₁、D₂、D_mUp to D_MThe following equation set can be set forth after the intensity of substance Z:

in the formula, the value of M is from 1 to M, and M is the thickness step number of the substance Z, namely the substance Z has M different thicknesses; the value of E is selected from E₁To E_nI.e. X-rays having n different intensities in the X-ray energy spectrum.

When the energy spectrum measurement is carried out, the material and the thickness of the substance Z can be set according to actual requirements, the absorption coefficient is determined after the material of the substance Z is determined, and the residual intensity of X-rays after the X-rays pass through the substance Z can be obtained by a ray energy spectrum measurement detector, so that only I in the equation set is₀(E) The energy of the X-ray can be obtained by solving the equation system, and an X-ray energy spectrum can be obtained when the X-ray with different intensities is used for irradiating the substance Z with the same thickness. Furthermore, the thickness step number of the substance Z is controlled by setting the value M, so that the equation set can obtain satisfactory precision in the least square method, and the precision of the energy spectrum measurement is improved.

Finally, the energy spectrum I of each X-ray pulse is obtained through fitting₀(E) (E from E₁To E_n) Then, the R value of any substance corresponding to the high-energy X-ray pulse energy spectrum and the low-energy X-ray pulse energy spectrum under any thickness (namely, image gray value) can be accurately calculated, so that the attribution of the maximum probability of each pixel in the image can be determined, and the substance classification precision is improved.

The material classification system of this embodiment, through install ray energy spectrum survey detector in the detector array just can survey the ray energy spectrum in real time at the in-process of material classification, guarantee that ray energy spectrum and ray generating device's operating condition accord with, and then improve the categorised precision of material, simple structure, convenient to use.

Claims

1. The utility model provides a material classification system, includes collimater, ray generating device and detector array, its characterized in that, include ordinary detector and ray energy spectrum survey detector in the detector array, the ray energy spectrum surveys the place that the detector setting is not sheltered from by the testee in the detector array, ray energy spectrum surveys the detector and includes the detector panel, the detector panel coats and is stamped a plurality of typical material pieces, typical material piece is used for surveying the ray energy spectrum.

2. The material classification system as recited in claim 1, wherein typical material blocks covering the detector panel are different from each other, and the typical material blocks are made of one of aluminum, graphite, steel, lead, and tungsten.

3. The substance sorting system according to claim 1 or 2, wherein the thickness of each typical mass covered on the detector panel is different.

4. The substance sorting system of claim 3, wherein the typical substance pieces covered on the detector panel are arranged in a step-like manner.

5. The substance classification system according to claim 1 or 2, characterized in that the radiation spectrometry detector is arranged at an edge position of the detector array.