阅读说明：本技术 一种γ核素放射源方位的快速测量方法 (Rapid measurement method for gamma nuclide radioactive source orientation ) 是由 唐智辉 韦应靖 以恒冠 王勇 冯梅 方登富 张庆利 黄亚雯 崔伟 于 2020-12-29 设计创作，主要内容包括：本发明涉及一种γ核素放射源方位的快速测量方法,所述方法包括以下步骤：步骤(1)、搭建探测系统,探测系统包括溴化镧闪烁探测器、屏蔽体以及分析软件；步骤(2)、利用蒙特卡洛模拟或者仪器实测,获得探头在各个角度测量时的全能峰计数率与角度的对应关系,获得全能峰计数率与角度的函数；利用蒙特卡洛模拟或者仪器实测,获取多个放射源的响应矩阵；步骤(3)、判断实际情形下是否有多个放射源；步骤(4)、若只有一个放射源,则先实测得到全能峰计数率,通过求解全能峰计数率与角度的函数得到放射源的角度；步骤(5)、若有多个放射源,则通过用反解响应矩阵方程,获得放射源的位置信息。利用该方法可以快速获取放射源方向信息。(The invention relates to a method for rapidly measuring the orientation of a gamma nuclide radioactive source, which comprises the following steps: step (1), a detection system is set up, wherein the detection system comprises a lanthanum bromide scintillation detector, a shield and analysis software; step (2), acquiring the corresponding relation between the counting rate of the full energy peak and the angle of the probe when the probe is measured at each angle by utilizing Monte Carlo simulation or actual measurement of an instrument, and acquiring a function of the counting rate of the full energy peak and the angle; acquiring response matrixes of a plurality of radioactive sources by Monte Carlo simulation or actual measurement of an instrument; step (3), judging whether a plurality of radioactive sources exist under the actual situation; step (4), if only one radioactive source exists, firstly, actually measuring to obtain the counting rate of the full energy peak, and obtaining the angle of the radioactive source by solving a function of the counting rate of the full energy peak and the angle; and (5) if a plurality of radioactive sources exist, obtaining the position information of the radioactive sources by solving a response matrix equation reversely. By the method, the direction information of the radioactive source can be quickly acquired.)

1. A method for rapidly measuring the orientation of a gamma nuclide radioactive source is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps of (1) building a detection system, wherein the detection system comprises a lanthanum bromide scintillation detector, a shield and analysis software, and the shield is positioned outside the lanthanum bromide scintillation detector;

utilizing Monte Carlo simulation or instrument actual measurement to obtain the corresponding relation between the full-energy peak counting rate and the angle of a lanthanum bromide scintillation detector probe when the lanthanum bromide scintillation detector probe and a single radioactive source form multiple angle measurement, and obtaining the function of the full-energy peak counting rate and the angle; utilizing Monte Carlo simulation or instrument actual measurement to obtain the corresponding relation between the full energy peak counting rate and the angle of the lanthanum bromide scintillation detector probe when the lanthanum bromide scintillation detector probe and a plurality of radioactive sources form a plurality of angle measurements, and obtaining the response matrix of the plurality of radioactive sources;

step (3), judging whether a plurality of radioactive sources exist under the actual situation;

step (4), if only one radioactive source exists, firstly, actually measuring to obtain the counting rate of the full energy peak, and obtaining the angle of the radioactive source by solving a function of the counting rate of the full energy peak and the angle;

and (5) if a plurality of radioactive sources exist, obtaining the position information of the radioactive sources by solving a response matrix equation reversely.

2. A method for rapid measurement of the orientation of a gamma-species radioactive source as defined in claim 1, wherein: the method for establishing the function of the counting rate and the angle of the full energy peak is as follows:

assuming that the detector is at a certain position, a coordinate system is established by taking the true east and the true north as the X axis and the Y axis respectively, assuming that when the radioactive source is in the four directions of the true east, the true west, the true south and the true north of the detector, the measured total energy peak counting rates are recorded as A, B, C, D respectively, a single radioactive source is arranged, and the included angle between the direction and the X axis is theta, then a relation formula theta ═ f (A, B, C and D) can be established.

3. A method for rapid measurement of the orientation of a gamma-species radioactive source as defined in claim 1, wherein:

the lanthanum bromide scintillation detector is a 0.5 'x 0.5' lanthanum bromide scintillation detector.

4. A method for rapid measurement of the orientation of a gamma-species radioactive source as defined in claim 1, wherein: the manufacturing method of the shielding body comprises the following steps: the acute angle vertex of two ends of the long right-angle side of a triangular lead sheet is coincided with the right-angle vertex, and the triangular lead sheet is rolled into a cylindrical shielding body along the right-angle side.

5. A method for rapid measurement of the orientation of a gamma-species radioactive source as defined in claim 1, wherein:

the method for acquiring the response matrix comprises the following steps: dividing a measuring area into m blocks, supposing that each block of area is internally provided with a radioactive source, for a certain radioactive source, rotating a shielding body to enable a detector probe to form n different angles with the radioactive source, measuring the full-energy peak counting rate of the detector under each angle, and obtaining a response matrix R, wherein R_ijThe full energy peak counting rate of the detector at the ith angle is as follows:

6. a method for rapid measurement of the orientation of a gamma-species radioactive source as defined in claim 5, wherein:

the specific method of the step (5) is that when a plurality of radioactive sources exist, the actually measured full-energy peak counting rate N of the detector in each area is measured_kK is 1, 2 … … m; solving equation (1), the angular information phi of the radiation source can be obtained:

7. a method for rapid measurement of gamma nuclide radiation source orientation as defined in claim 6 wherein said equation (1) is solved using an iterative algorithm based on maximum entropy.

Technical Field

The invention belongs to the technical field of radiation detection, and particularly relates to a method for rapidly measuring the orientation of a gamma nuclide radioactive source.

Background

The gamma energy spectrum analysis technology is an important means for rapidly, reliably and nondestructively determining the properties and the intensities of various radionuclides with gamma radiation in a sample to be detected, and is a relatively intuitive instrument analysis technology. It plays a great role in nuclear physics research, geological survey, environmental radioactivity research, homeland safety and other aspects.

The gamma spectrometer mainly adopts NaI scintillation crystals to realize gamma detection and nuclide identification, when charged or uncharged particles with higher energy pass through a scintillator, the energy of the charged or uncharged particles is absorbed, so that molecules or atoms of the materials are excited and ionized, when the excited molecules or atoms return to a ground state from an excited state, the energy is released in the form of photons, the emitted photons have a specific energy spectrum and are called as scintillation light, the characteristics of various rays can be analyzed and recorded by measuring the luminescence spectrum of the scintillation light, so that the luminescence position of the rays can be measured, and the scintillation detector can be used for positioning and imaging of the rays.

However, the crystal of the commonly used scintillator probe is cylindrical, the response to the lateral gamma rays is isotropic, and the measured data does not contain directional information; furthermore, in the case of a radiation source having multiple identical nuclides, the measured data also does not allow distinguishing the location of each source.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for quickly measuring the orientation of a gamma nuclide radioactive source so as to quickly acquire the direction information of the radioactive source.

In order to achieve the above purposes, the invention adopts the technical scheme that:

a method for rapid measurement of gamma-nuclide radiation source orientation, the method comprising the steps of:

the method comprises the following steps of (1) building a detection system, wherein the detection system comprises a lanthanum bromide scintillation detector, a shield and analysis software, and the shield is positioned outside the lanthanum bromide scintillation detector;

utilizing Monte Carlo simulation or instrument actual measurement to obtain the corresponding relation between the full-energy peak counting rate and the angle of a lanthanum bromide scintillation detector probe when the lanthanum bromide scintillation detector probe and a single radioactive source form multiple angle measurement, and obtaining the function of the full-energy peak counting rate and the angle; utilizing Monte Carlo simulation or instrument actual measurement to obtain the corresponding relation between the full energy peak counting rate and the angle of the lanthanum bromide scintillation detector probe when the lanthanum bromide scintillation detector probe and a plurality of radioactive sources form a plurality of angle measurements, and obtaining the response matrix of the plurality of radioactive sources;

step (3), judging whether a plurality of radioactive sources exist under the actual situation;

step (4), if only one radioactive source exists, firstly, actually measuring to obtain the counting rate of the full energy peak, and obtaining the angle of the radioactive source by solving a function of the counting rate of the full energy peak and the angle;

and (5) if a plurality of radioactive sources exist, obtaining the position information of the radioactive sources by solving a response matrix equation reversely.

Further, the function of the count rate and the angle of the total energy peak is established as follows:

assuming that the detector is at a certain position, a coordinate system is established by taking the true east and the true north as the X axis and the Y axis respectively, assuming that when the radioactive source is in the four directions of the true east, the true west, the true south and the true north of the detector, the measured total energy peak counting rates are recorded as A, B, C, D respectively, a single radioactive source is arranged, and the included angle between the direction and the X axis is theta, then a relation formula theta ═ f (A, B, C and D) can be established.

Further, the lanthanum bromide scintillation detector is a 0.5 "x 0.5" lanthanum bromide scintillation detector.

Further, the manufacturing method of the shielding body comprises the following steps: the acute angle vertex of two ends of the long right-angle side of a triangular lead sheet is coincided with the right-angle vertex, and the triangular lead sheet is rolled into a cylindrical shielding body along the right-angle side.

Further, the method for acquiring the response matrix is as follows: dividing a measuring area into m blocks, supposing that each block of area is internally provided with a radioactive source, for a certain radioactive source, rotating a shielding body to enable a detector probe to form n different angles with the radioactive source, measuring the full-energy peak counting rate of the detector under each angle, and obtaining a response matrix R, wherein R_ijThe full energy peak counting rate of the detector at the ith angle is as follows:

further, the specific method of the step (5) is that when a plurality of radioactive sources exist, the actually measured full energy peak counting rate N of the detector in each area is measured_kK is 1, 2 … … m; solving equation (1), the angular information phi of the radiation source can be obtained:

further, the equation (1) is solved using an iterative algorithm based on maximum entropy.

The invention has the beneficial technical effects that:

the invention designs a novel spectrometer detection system, which combines an algorithm of response matrix inverse solution to realize the rapid positioning of a plurality of nuclides and a plurality of gamma radioactive sources, can realize the identification of the nuclides, provides more accurate information and provides data for the next step of measures.

Drawings

FIG. 1 is a flow chart of a method for rapidly measuring the orientation of a gamma-species radiation source provided by the present invention;

FIG. 2 is a schematic diagram of an expanded configuration of the shield according to an embodiment of the present invention;

fig. 3 is a block diagram of a measurement region according to an embodiment of the present invention.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

The invention provides a method for rapidly measuring the orientation of a gamma nuclide radioactive source, which comprises the following steps as shown in figure 1:

step (1), a detection system is set up, wherein the detection system comprises a lanthanum bromide scintillation detector, a shield and analysis software; the lanthanum bromide scintillation detector is a 0.5 'x 0.5' lanthanum bromide scintillation detector. The shield is positioned outside the lanthanum bromide scintillation detector, and the manufacturing method of the shield comprises the following steps: the acute angle vertex and the right angle vertex at two ends of the long right angle side of a triangular lead sheath shown in figure 2 are coincided, and a cylindrical shielding body is rolled along the right angle side. A special shielding layer is added on the outer part of the conventional probe, so that the whole probe has a directional response difference to gamma rays incident in a side direction.

Utilizing Monte Carlo simulation or instrument actual measurement to obtain the corresponding relation between the full-energy peak counting rate and the angle of a lanthanum bromide scintillation detector probe when the lanthanum bromide scintillation detector probe and a single radioactive source form multiple angle measurement, and obtaining the function of the full-energy peak counting rate and the angle; and (3) obtaining the corresponding relation between the full energy peak counting rate and the angle of the lanthanum bromide scintillation detector probe when the lanthanum bromide scintillation detector probe and a plurality of radioactive sources form a plurality of angle measurements by utilizing Monte Carlo simulation or instrument actual measurement, and obtaining the response matrix of the plurality of radioactive sources.

The method for establishing the function of the counting rate and the angle of the full energy peak is as follows:

assuming that the detector is at a certain position, a coordinate system is established by taking the true east and the true north as the X axis and the Y axis respectively, assuming that when the radioactive source is in the four directions of the true east, the true west, the true south and the true north of the detector, the measured total energy peak counting rates are recorded as A, B, C, D respectively, a single radioactive source is arranged, and the included angle between the direction and the X axis is theta, then a relation formula theta ═ f (A, B, C and D) can be established.

The method for acquiring the response matrix comprises the following steps: as shown in fig. 3, the measurement area is divided into m blocks, assuming that there is a radioactive source in each block, for a certain radioactive source, the detector probe and the radioactive source form n different angles by rotating the shielding body, the full-energy peak count rate of the detector at each angle is measured, and a response matrix R is obtained, where R is_ijThe full energy peak counting rate of the detector at the ith angle is as follows:

step (3), judging whether a plurality of radioactive sources exist under the actual situation;

step (4), if only one radioactive source exists, firstly, actually measuring to obtain the counting rate of the full energy peak, and obtaining the angle of the radioactive source by solving a function of the counting rate of the full energy peak and the angle;

step (5) when a plurality of radioactive sources exist, measuring the actually measured full-energy peak counting rate N of the detector in each area_kK is 1, 2 … … m; equation (1) is solved using an iterative algorithm based on maximum entropy. Then the angular information of the radiation source phi can be obtained:

the above-described embodiments are merely illustrative of the present invention, which may be embodied in other specific forms or in other specific forms without departing from the spirit or essential characteristics thereof. The described embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. The scope of the invention should be indicated by the appended claims, and any changes that are equivalent to the intent and scope of the claims should be construed to be included therein.