Liquid flash measurement method using pulse photomask
阅读说明：本技术 一种使用脉冲光罩的液闪测量方法 (Liquid flash measurement method using pulse photomask ) 是由 梁金胜 于 2019-11-21 设计创作，主要内容包括：本发明涉及一种使用脉冲光罩的液闪测量方法,能够获取在脉冲光源的标准脉冲条件下系统的单位时间内的实际计数CPM和对应的TDCR值,尤其是设计了配套光罩用于滤光,并尽量与样品容器材质和形状保持一致,使得光电倍增管接收到的光线波段在监测状态和实际测量状态保持一致,为了定位准确特别设计了环状凹槽定位标记,使操作更精确,大大减小了监测系统的错误提示。(The invention relates to a liquid flash measurement method using a pulse photomask, which can acquire the actual count CPM and the corresponding TDCR value of a system in unit time under the standard pulse condition of a pulse light source, particularly designs a matched photomask for filtering light and keeps the same with the material and the shape of a sample container as much as possible, so that the light wave band received by a photomultiplier keeps the same with the actual measurement state in the monitoring state, and particularly designs an annular groove positioning mark for accurate positioning, so that the operation is more accurate, and the error prompt of a monitoring system is greatly reduced.)
1. A liquid flash measurement method using a pulse mask is characterized by comprising the following steps:
step one, establishing electronic original data, namely, when the liquid flash measuring instrument is used for the first time, arranging a pulse light source in a sample bearing unit, wherein a pulse light cover is of a bottle-shaped structure without a bottom and comprises a light cover body and a light cover main body, the light cover body can cover an opening in the upper part of the light cover main body, the pulse light source is covered by the pulse light cover, the pulse light source is controlled to work under different flash frequencies, a plurality of groups of actual counting CPM and triple-double coincidence ratio TDCR values collected by a photomultiplier tube in unit time are obtained through the photomultiplier tube, the pulse light source is a pulse light source carried by the system, the peak flash capacity is less than 20 joules, the pulse width is 0.2-0.8s, and the flash frequency adjustable range is about 60-100 times/minute;
step two, electronic data monitoring, namely, before each measurement of a standard sample and a sample to be measured, performing electronic data monitoring through the pulse light source in the step one, specifically, turning on the pulse light source, setting a flash frequency, covering the pulse light source with a pulse light cover in a manner similar to the step one, recording current CPM and TDCR values, and storing and recording at least two groups of data;
step three, calculating, namely performing data fitting on the CPM and the TDCR value in the step one to obtain a fitting curve, and calculating a difference value between the last CPM value and the last CPM value in the step two;
step four, a logic judgment step, namely, if the difference value in the step three is zero or is within a set threshold range, directly comparing the TDCR value corresponding to the last CPM value with the TDCR value corresponding to the penultimate CPM value to obtain the difference value of the TDCR values; if the difference value is out of the set threshold range, substituting the CPM value of the last time into the fitting curve to calculate the corresponding TDCR value, and comparing the calculated TDCR value with the TDCR value corresponding to the CPM value of the second time to obtain the difference value of the TDCR values; if the difference value of the two TDCR values is within the set threshold range, the influence of the electronic quenching is not large, and the user can be prompted to continue to measure the sample in the step six, and if the difference value of the TDCR values is outside the set threshold range, the influence of the electronic quenching is large, large measurement errors can be caused, and the user needs to be prompted to check electronic devices and circuits and perform the step five;
step five, electronic data updating, namely after the electronic device and the line are repaired, repeating the step four until the difference value of the TDCR values is within a set threshold range, and storing the TDCR value corresponding to the last CPM value as comparison data for next logic judgment;
and step six, performing a conventional quenching correction step and a to-be-measured sample measurement step.
2. A liquid flash measurement method according to claim 1, characterized in that: the material and the shape of the main body of the pulse photomask, the material and the shape of the container of the standard sample and the material and the shape of the container of the sample to be detected are the same.
Technical Field
The invention relates to the measurement of nuclear radiation or X-ray radiation, in particular to the measurement field of X-ray radiation, gamma-ray radiation, corpuscular radiation or cosmic radiation, in particular to the measurement of the radiation intensity of a scintillation detector of which a scintillator is liquid, and particularly to a liquid scintillation measurement method.
Background
The liquid scintillation measurement (liquid scintillation for short) technology is an effective method for measuring low-energy beta rays developed in the early fifties of the twentieth century, and can also be used for detecting other nuclear radiation, such as alpha rays, neutrons, gamma rays and other radiation.
However, in actual measurement, because interference of various factors causes limited measurement accuracy, the main influencing factor is influence of quenching, the quenching is of various types and comprises phase quenching, ionization quenching, concentration quenching, chemical quenching, color quenching and the like, so that the counting efficiency of a sample becomes low (CPM/DPM value becomes small, CPM represents the counting rate of a liquid flash measuring instrument to the sample per minute; DPM represents the absolute decay variable of the sample per minute, and the percentage of the two is called the counting efficiency of the sample). The known quenching correction method produced by various manufacturers in the prior art mainly comprises an internal standard method, an external standard method, an efficiency tracing method and the like, wherein no matter which method is adopted, an index capable of directly or indirectly representing the counting efficiency is essentially found, the index is measurable in a physical sense, when a sample is measured, the current counting efficiency can be known through the measurable index, so that the DPM can be calculated from the CPM of a measured value, the internal standard method belongs to a direct representation mode, but a specially configured liquid scintillation liquid is required, the external standard method must be fitted with a group of indexes related to the quenching degree and the counting efficiency, however, the external standard method cannot simulate the property of the liquid scintillation solution, the error of the measured result is often larger, the reduction of the error and the improvement of the measuring precision become the efforts of technicians in the field, and the known methods, those skilled in the art are generally concerned with keeping the measurement of the standard sample and the measurement of the sample to be measured under the same measurement conditions to reduce errors, but the conditions of the instrument, including the condition of the photoelectric sensor itself, may change from moment to moment, and the art does not have a good monitoring method to correct the possible performance fluctuation errors of the instrument itself, or the art does not find that the problem is actually a significant part of the error generation.
Disclosure of Invention
On the basis of the prior art, a technical team of the applicant researches a liquid flash measuring instrument and a related quenching correction method or a method for monitoring error generation (comprising three available schemes, wherein each scheme is divided into a main unit, and the whole device and the method are arranged), puts forward errors of the instrument, puts forward a solution, can obviously improve the measuring precision, has an unexpected technical effect, and still has a space for further improving the precision through further research of technicians on the basis.
The invention relates to a matched measuring device which is designed aiming at a liquid flash measuring instrument capable of monitoring the electronic quenching condition and is designed aiming at the technical team of the applicant, mainly aiming at further improving the monitoring precision and correspondingly designing a corresponding measuring method.
In order to achieve the purpose, the invention is realized by the following technical scheme:
the method is realized based on a liquid flash measuring instrument system, wherein the liquid flash measuring instrument comprises a sample bearing unit, a driving unit, a measuring unit, a calculation control unit and a pulse light source; the driving unit comprises a rotating platform and a plurality of driving motors, the sample bearing unit is arranged on the rotating platform, the whole sample bearing unit and one part of the rotating platform are arranged in the shell of the measuring unit, the other part of the rotating platform and the driving motors are arranged outside the shell of the measuring unit, the driving motors are at least two driving motors which are respectively used for driving the rotating platform to rotate and driving the pulse light source to ascend and descend, the rotating platform is communicated with the inside of the sample bearing unit, the pulse light source is arranged in the rotating platform and can be driven to extend into the inside of the sample bearing unit, the top of the pulse light source is of a plane structure, when the pulse light source is completely arranged in the rotating platform, the top of the pulse light source is used as one part of the bottom of the sample bearing unit, and the one part of the bottom and the other part of the bottom of the sample, the utility model discloses a sample bearing unit, including the sample bearing unit, the sample bearing unit's another part bottom is provided with cyclic annular mark, cyclic annular mark can surround pulse light source's top region, the pulse light cover is the bottle column structure of no bottom, including the light cover lid, and light cover body, light cover lid can cover light cover body upper portion opening, and light cover body lower part opening has the ring shape the same with cyclic annular mark, cyclic annular mark is setting up the annular groove on the sample bearing unit's another part bottom, light cover body lower part can insert in this recess, the material of light cover body is low potassium glass, wholly is the cylinder structure, light cover body lower part external diameter 30 millimeters,
The invention provides a liquid flash measurement method using a pulse photomask based on the design of the pulse photomask, and the measurement method comprises the following steps:
step one, establishing electronic original data, namely driving and lifting a pulse light source into a sample bearing unit when a liquid flash measuring instrument is used for the first time, inserting the lower part of a pulse light cover main body into a groove-shaped annular mark, enabling the pulse light cover to cover the pulse light source, controlling the pulse light source to work under different flash frequencies, and acquiring actual count CPM and triple-double coincidence ratio TDCR values in unit time acquired by a plurality of groups of photomultiplier tubes through the photomultiplier tubes, wherein the pulse light source is a pulse light source carried by a system, the peak flash capacity is less than 20 joules, the pulse width is 0.2-0.8s, and the flash frequency adjustable range is 60-100 times/minute;
step two, electronic data monitoring, namely, before each measurement of a standard sample and a sample to be measured, performing electronic data monitoring through the pulse light source in the step one, specifically, turning on the pulse light source, setting a flash frequency, covering the pulse light source with a pulse light cover in a manner similar to the step one, recording current CPM and TDCR values, and storing and recording at least two groups of data;
step three, calculating, namely performing data fitting on the CPM and the TDCR value in the step one to obtain a fitting curve, and calculating a difference value between the last CPM value and the last CPM value in the step two;
step four, a logic judgment step, namely, if the difference value in the step three is zero or is within a set threshold range, directly comparing the TDCR value corresponding to the last CPM value with the TDCR value corresponding to the penultimate CPM value to obtain the difference value of the TDCR values; if the difference value is out of the set threshold range, substituting the CPM value of the last time into the fitting curve to calculate the corresponding TDCR value, and comparing the calculated TDCR value with the TDCR value corresponding to the CPM value of the second time to obtain the difference value of the TDCR values; if the difference value of the two TDCR values is within the set threshold range, the influence of the electronic quenching is not large, and the user can be prompted to continue to measure the sample in the step six, and if the difference value of the TDCR values is outside the set threshold range, the influence of the electronic quenching is large, large measurement errors can be caused, and the user needs to be prompted to check electronic devices and circuits and perform the step five;
step five, electronic data updating, namely after the electronic device and the line are repaired, repeating the step four until the difference value of the TDCR values is within a set threshold range, and storing the TDCR value corresponding to the last CPM value as comparison data for next logic judgment;
and step six, performing a conventional quenching correction step and a to-be-measured sample measurement step.
Furthermore, the material and the shape of the body of the pulse photomask, the material and the shape of the container of the standard sample and the material and the shape of the container of the sample to be measured are the same.
Compared with the prior art, the invention has the advantages that:
Drawings
FIG. 1 is the overall structure of the liquid scintillation meter of the present invention.
FIG. 2 is a schematic diagram of the top of the pulsed light source of the present invention in cooperation with the bottom of another portion of the sample support unit.
FIG. 3 is a schematic diagram of a pulse mask and a ring mark for inserting the pulse mask into a groove structure according to the present invention
In the figure: 1. the sample bearing unit comprises a sample bearing unit 1.1, the bottom of the other part of the sample bearing unit 2.1, a rotating table driving motor 2.2, a pulse light
Detailed Description
The present invention is further described with reference to the accompanying drawings, as mentioned in the background art, there are many ways to characterize the quenching degree, and how to suggest the relationship between the characterization parameters and the actual quenching degree by not changing the properties of the sample itself, such as the principle and calculation method of the TDCR value mentioned in the present invention and other commonly used characterization parameters (SCR, SIS, ESR, H value, etc.) not mentioned in the present invention belong to the prior art, the present invention takes TDCR as an example, and not only applies this value, but also other values can be applied, and DPM and CPM, the counting efficiency is also a fixed term in the art and has its known meaning, the abbreviation mentioned in the present invention is a known definition, and will not be described in detail in the present application, and the used standard samples are all common standard samples sold in the market, for example, a series of standard quenching samples are all known types in the art except for special description, the proportions and components thereof are not particularly described.
With reference to fig. 1-3, the liquid flash measuring instrument of the present invention comprises a sample carrying unit (1), a driving unit, a measuring unit (4), a calculation control unit (7), and a pulse light source (5); the driving unit comprises a rotating platform (3) and a plurality of driving motors (2.1, 2.2), the sample bearing unit (1) is arranged on the rotating platform (3), the whole sample bearing unit (1) and one part of the rotating platform (3) are arranged in a shell (6) of the measuring unit, the other part of the rotating platform and the plurality of driving motors (2.1, 2.2) are arranged outside the shell (6) of the measuring unit, the plurality of driving motors are at least two driving motors (2.1, 2.2) which are respectively used for driving the rotating platform (3) to rotate and driving the pulse light source (5) to ascend and descend, the rotating platform (3) is communicated with the inside of the sample bearing unit (1), the pulse light source (5) is arranged inside the rotating platform (3), the top part (5.1) of the pulse light source (5) is of a plane structure and can be driven to extend into the sample bearing unit (1), when the pulse light source (5) is completely arranged inside the rotating platform (3), the top (5.1) of the pulse light source is used as a part of the bottom of the sample bearing unit (1), and the part of the bottom and the other part of the bottom (1.1) of the sample bearing unit form the complete bottom of the sample bearing unit; another part bottom of sample bearing unit is provided with cyclic annular mark (9), cyclic annular mark (9) can surround pulse light source's top region, and cyclic annular mark (9) set up the ring form recess on another part bottom (1.1) of sample bearing unit, the pulse light cover is the bottle column structure of no bottom, including light cover lid (11), and light cover main part (10), light cover lid (11) can cover light cover main part upper portion opening, and light cover main part lower part opening has the same ring shape with cyclic annular mark, and light cover main part lower part terminal surface can insert in this recess, works as pulse light source.
The liquid flash measuring instrument of the invention can provide a container for containing samples (including standard samples and samples to be measured) for containing scintillation liquid, the material and the shape of the photomask main body are the same as those of the container, the difference is only that no bottom seal is arranged, the preferable practical mode is the same as the common material, the photomask main body is made of low-potassium glass, the whole structure is a cylinder structure, in order to be suitable for the design of the invention, the outer diameter of the lower part of the photomask main body is 30 mm, the wall thickness of the glass is 1 mm, and the material of the photomask cover is polytetrafluoroethylene, so that the diffuse reflection of light can be increased, and the measurement.
When in use, the measurement precision can be improved through the following steps:
step one, establishing electronic original data, namely driving and lifting a pulse light source into a sample bearing unit when a liquid flash measuring instrument is used for the first time, inserting the lower part of a pulse light cover main body into a groove-shaped annular mark, enabling the pulse light cover to cover the pulse light source, controlling the pulse light source to work under different flash frequencies, and acquiring actual count CPM and triple-double coincidence ratio TDCR values in unit time acquired by a plurality of groups of photomultiplier tubes through the photomultiplier tubes, wherein the pulse light source is a pulse light source carried by a system, the peak flash capacity is less than 20 joules, the pulse width is 0.2-0.8s, and the flash frequency adjustable range is 60-100 times/minute;
step two, electronic data monitoring, namely, before each measurement of a standard sample and a sample to be measured, performing electronic data monitoring through the pulse light source in the step one, specifically, turning on the pulse light source, setting a flash frequency, covering the pulse light source with a pulse light cover in a manner similar to the step one, recording current CPM and TDCR values, and storing and recording at least two groups of data;
step three, calculating, namely performing data fitting on the CPM and the TDCR value in the step one to obtain a fitting curve, and calculating a difference value between the last CPM value and the last CPM value in the step two;
step four, a logic judgment step, namely, if the difference value in the step three is zero or is within a set threshold range, directly comparing the TDCR value corresponding to the last CPM value with the TDCR value corresponding to the penultimate CPM value to obtain the difference value of the TDCR values; if the difference value is out of the set threshold range, substituting the CPM value of the last time into the fitting curve to calculate the corresponding TDCR value, and comparing the calculated TDCR value with the TDCR value corresponding to the CPM value of the second time to obtain the difference value of the TDCR values; if the difference value of the two TDCR values is within the set threshold range, the influence of the electronic quenching is not large, and the user can be prompted to continue to measure the sample in the step six, and if the difference value of the TDCR values is outside the set threshold range, the influence of the electronic quenching is large, large measurement errors can be caused, and the user needs to be prompted to check electronic devices and circuits and perform the step five;
step five, electronic data updating, namely after the electronic device and the line are repaired, repeating the step four until the difference value of the TDCR values is within a set threshold range, and storing the TDCR value corresponding to the last CPM value as comparison data for next logic judgment;
and step six, performing a conventional quenching correction step and a to-be-measured sample measurement step.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.