Liquid flash measuring instrument for correcting color quenching
阅读说明：本技术 一种针对颜色淬灭进行校正的液闪测量仪 (Liquid flash measuring instrument for correcting color quenching ) 是由 梁金胜 于 2019-11-21 设计创作，主要内容包括：本发明提供了一种针对颜色淬灭进行校正的液闪测量仪,使用标准淬灭样品后,又单独使用特别设计的光强标准灯和硅光电二极管来建立被液闪溶液吸光后的实测光强和计数效率的关系,因为颜色深浅和吸光程度成正相关,巧妙的建立了光强和因颜色淬灭影响的计数效率之间的关系,在测量未知样品时,可以很方便的通过测量光强进一步修正计数效率,取得了本领域可预期的常规效果之外的技术效果,并且方便操作,提高了测量精度。(The invention provides a liquid flash measuring instrument for correcting color quenching, which is characterized in that after a standard quenching sample is used, a specially designed light intensity standard lamp and a silicon photodiode are independently used for establishing the relation between the actually measured light intensity after light absorption by a liquid flash solution and the counting efficiency.)
1. A liquid flash measuring instrument for correcting color quenching comprises a sample bearing unit (1), a driving unit (2), a measuring unit (4) and a calculation control unit (7); the method is characterized in that: the drive unit (2) comprises a drive motor and a rotating platform (3), 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 (3) and the drive motor are arranged outside the shell (6) of the measuring unit, the drive motor is used for driving the rotating platform (3) to rotate so as to drive the sample bearing unit (1) to rotate, and at least three photomultiplier tubes (PM 1-PM 3) are further arranged in the shell (6) of the measuring unit.
2. A liquid flash measuring instrument as claimed in claim 1, wherein: simultaneously arranging a light intensity standard lamp (5, SLS) and a corresponding silicon photodiode, wherein when the sample is placed on the sample bearing unit (1), the photomultiplier (PM 1-PM 3), the light intensity standard lamp (5, SLS) and the silicon photodiode surround the sample; the calculation control unit (7) is connected with the photomultiplier, the light intensity standard lamp, the silicon photodiode and the driving motor and is used for controlling the light intensity standard lamp to emit light rays with standard light intensity, receiving measurement signals of the silicon photodiode, collecting the measurement signals of the photomultiplier, calculating and controlling the driving motor to drive.
3. A liquid flash measuring instrument according to claim 1 or 2, wherein: the light intensity standard lamp is a tungsten lamp, the area of the light receiving surface of the silicon photodiode is larger than 100 square millimeters, and the distance between the light receiving surface of the silicon photodiode and the tungsten lamp is not more than about 36 cm.
4. A liquid flash measuring instrument according to any one of claims 1 to 3, wherein: when the photomultiplier tube, the light intensity standard lamp and the silicon photodiode surround the sample, the sample is substantially at the midpoint of the light receiving surfaces of the light intensity standard lamp and the silicon photodiode.
Technical Field
The invention relates to the measurement of nuclear radiation or X-ray radiation, in particular to the field of measurement of X-ray radiation, gamma-ray radiation, corpuscular radiation or cosmic radiation, in particular to the measurement of radiation intensity of a scintillation detector of which a scintillator is liquid, and particularly relates to a liquid flash measuring instrument and a measurement method of the liquid flash measuring instrument.
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 can be fitted only by 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 liquid, the error of the measured result is large, and the reduction of the error and the improvement of the measuring accuracy become the efforts of technicians in the field.
Therefore, on the basis of the prior art, a technical team of the applicant researches a liquid flash measuring instrument (actually, three available schemes are researched, the application relates to one scheme, the other two schemes are filed in another scheme, each scheme is divided into main units, and the whole device and the method are arranged), the influence of color quenching factors in an external standard method needs to be noticed for the first time, the field generally considers that the external standard method corrects the main quenching problem, however, the research of the technical team of the applicant finds that if the color quenching is additionally corrected on the basis of the correction of the prior art, the measurement accuracy can be obviously improved, and the technical effect is unexpected.
Disclosure of Invention
In view of the above problems in the prior art, the present invention provides a liquid flash measuring instrument for correcting color quenching, and mainly aims to provide a liquid flash measuring device and method with higher accuracy.
In order to achieve the purpose, the invention is realized by the following technical scheme:
a liquid flash measuring instrument comprises a sample bearing unit, a driving unit, a measuring unit and a calculation control unit; the driving unit comprises a driving motor and a rotating platform, 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 a shell of the measuring unit, the other part of the rotating platform and the driving motor are arranged outside the shell of the measuring unit, the driving motor is used for driving the rotating platform to rotate so as to drive the sample bearing unit to rotate, at least three photomultiplier tubes are further arranged in the shell of the measuring unit, and a light intensity standard lamp and a corresponding silicon photodiode are arranged at the same time; the calculation control unit is connected with the photomultiplier, the light intensity standard lamp, the silicon photodiode and the driving motor and is used for controlling the light intensity standard lamp to emit light rays with standard light intensity, receiving measurement signals of the silicon photodiode, collecting the measurement signals of the photomultiplier, calculating and controlling the driving motor to drive.
Further, the light intensity standard lamp is a tungsten lamp, the area of the light receiving surface of the silicon photodiode is larger than 100 square millimeters, and the distance between the light receiving surface of the silicon photodiode and the tungsten lamp is not more than 36 cm.
Further, when the photomultiplier, the light intensity standard lamp, and the silicon photodiode surround the sample, the sample is substantially at the midpoint of the light receiving surfaces of the light intensity standard lamp and the silicon photodiode.
The measuring method of the liquid flash measuring instrument comprises the following steps:
the method comprises the steps of firstly, establishing a quenching rule relation, namely placing a series of standard quenching samples of an absolute decay variable DPM in a known unit time on a sample bearing unit, turning off a light intensity standard lamp, and obtaining actual count CPM and triple-double coincidence ratio TDCR values in the unit time of the series of standard quenching samples in the state through a photomultiplier, wherein the series of standard quenching samples are commercially available common series standard quenching samples;
secondly, establishing a color quenching rule relation, namely placing a series of standard color quenching samples of the DPM in a known unit time on a sample bearing unit, turning on a light intensity standard lamp, and acquiring actual count CPM and light intensity data actually measured by a silicon photodiode of the series of standard color quenching samples in the unit time through a photomultiplier tube;
step three, a measuring step, namely arranging a sample to be measured of unknown DPM on a sample bearing unit, keeping a light intensity standard lamp closed, measuring a TDCR value and a CPM value, turning on the light intensity standard lamp, and measuring light intensity data by using a silicon photodiode;
step four, calculating, namely, making a ratio of the CPM value in the step one to the DPM value of the corresponding standard sample, and fitting the obtained ratio and the corresponding TDCR value to obtain a fitting curve of standard quenching counting efficiency and TDCR; and (3) making a ratio of the CPM value in the step two to the DPM value of the corresponding standard color quenching sample, fitting the obtained ratio and the corresponding light intensity value to obtain a color quenching counting efficiency and light intensity fitting curve, substituting the light intensity data in the step three into the color quenching counting efficiency and light intensity fitting curve to obtain the color quenching counting efficiency, substituting the TDCR value in the step three into the standard quenching counting efficiency and TDCR fitting curve to obtain the standard quenching counting efficiency, and dividing the CPM value of the sample to be measured in the
Compared with the prior art, the invention has the advantages that:
1) the invention breaks the conventional thought of the traditional design and provides a novel quenching degree correction and measurement mode, the traditional design thought is limited to the configuration of different standard quenching samples, the chemical quenching and the color quenching can be simultaneously corrected, the technical team of the applicant discovers that if the chemical quenching and the color quenching are simultaneously corrected, the fitting degree is not good in practice, and the error is larger, after the standard quenching samples are used, the invention independently uses a specially designed light intensity standard lamp and a silicon photodiode to establish the relationship between the actually measured light intensity after the light absorption of the liquid flash solution and the counting efficiency, because the color depth and the light absorption degree are in positive correlation, the relationship between the light intensity and the counting efficiency influenced by the color quenching is ingeniously established, when an unknown sample is measured, the counting efficiency can be further corrected by measuring the light intensity, the technical effect beyond the conventional effect expected in the field is achieved, the operation is convenient, and the measurement precision is improved;
2) the invention uses the rotatable sample bearing unit, can judge whether the liquid flash solution is uniform through rotation, and avoids the error caused by non-uniformity during color quenching correction, and the mode belongs to the initiative of the invention.
Drawings
Fig. 1 is a schematic structural diagram of a measuring unit and a calculation control unit of the present invention.
Fig. 2 is the whole structure of the liquid scintillation meter of the invention.
In the figure: 1. the device comprises a
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 and 2, the liquid flash measuring instrument of the present invention comprises a sample carrying unit (1), a driving unit (2), a measuring unit (4), and a calculation control unit (7); the driving unit (2) comprises a driving motor and a rotating platform (3), 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 (3) and a driving motor are arranged outside the shell (6) of the measuring unit, the driving motor is used for driving the rotating platform (3) to rotate so as to drive the sample bearing unit (1) to rotate, at least three photomultiplier tubes (PM 1-PM 3) are also arranged in the shell (6) of the measuring unit, simultaneously, a light intensity standard lamp (5, SLS) and a corresponding silicon photodiode are arranged, when a sample is placed on the sample bearing unit (1), a photomultiplier tube (PM 1-PM 3), a light intensity standard lamp (5, SLS) and a silicon photodiode surround the sample; the calculation control unit (7) is connected with the photomultiplier, the light intensity standard lamp, the silicon photodiode and the driving motor and is used for controlling the light intensity standard lamp to emit light rays with standard light intensity, receiving measurement signals of the silicon photodiode, collecting the measurement signals of the photomultiplier, calculating and controlling the driving motor to drive.
The light intensity standard lamp is a tungsten lamp, the wavelength of 400-760 nm emitted by a light source of the tungsten lamp can generate a good matching absorption effect with a standard color quenching sample using methyl red acetone saturated liquid as a color quenching agent, the area of a light receiving surface of a silicon photodiode is larger than 100 square millimeters, and according to GIE standard recommendation, the distance between the light receiving surface of the silicon photodiode and the tungsten lamp is not more than 31.6cm, in an actual experiment, the distance is inconsistent with the known distance, and the measurement effect is obviously influenced only when the distance exceeds 36cm by unexpected discovery.
Further, when the photomultiplier, the light intensity standard lamp, and the silicon photodiode surround the sample, the sample is substantially at the midpoint of the light receiving surfaces of the light intensity standard lamp and the silicon photodiode, and it is understood that the midpoint is not a strict midpoint as long as it is substantially at the middle of the light path so that the line from the tungsten lamp can pass through the sample.
The invention also relates to a quenching correction unit of the liquid flash measuring instrument, which belongs to a part of a calculation control unit of the liquid flash measuring instrument and comprises the following components:
a light intensity standard lamp control unit for controlling the light intensity standard lamp to be turned on and off;
a quenching data collection unit capable of acquiring an actual count CPM per unit time of a sample and calculating a TDCR value when quenching the sample using a standard series;
a fitting correction unit for fitting the ratio (counting efficiency) of CPM to DPM and the TDCR value in the quenching data collection unit to obtain a fitting curve;
the color quenching correction unit is used for acquiring actually measured light intensity data when a standard color quenching sample is used, fitting the counting efficiency of the standard color quenching sample and the actually measured light intensity data of the silicon photodiode to obtain a fitting curve, and acquiring the actually measured light intensity data when an unknown activity sample is measured;
and the calculation unit is used for substituting the actually measured light intensity data of the photodiode into the fitting curve obtained by the color quenching correction unit when measuring the unknown activity sample, calculating the color quenching counting efficiency, substituting the TDCR value into the fitting correction unit to obtain the standard quenching counting efficiency, calculating the DPM value according to the color quenching counting efficiency, the standard quenching counting efficiency and the CPM value of the sample to be measured, and outputting the value to a user.
Further, the light intensity standard lamp control unit keeps the light intensity standard lamp in an off state when the standard series quenching sample is used.
The functional units can be integrated in a computer and realized through conventional logic, calculation, storage and other units of the computer, or respectively realized through respectively setting corresponding upper computer functional units, and can be set according to specific requirements, and the two setting methods do not substantially influence the concept of the invention and are not particularly limited.
The invention also relates to a measuring method of the liquid flash measuring instrument, which comprises the following steps:
the method comprises the steps of firstly, establishing a quenching rule relation, namely placing a series of standard quenching samples of an absolute decay variable DPM in a known unit time on a sample bearing unit, turning off a light intensity standard lamp, and obtaining an actual count CPM and a triple-double coincidence ratio TDCR value of the series of standard quenching samples in the unit time under the state through a photomultiplier, wherein the series of standard quenching samples are commercially available common series standard quenching samples, and at least 5 samples with different quenching degrees are provided so as to have enough fitting data;
secondly, establishing a color quenching rule relation, namely placing a series of standard color quenching samples with known absolute decay variable DPM in unit time on a sample bearing unit, turning on a light intensity standard lamp, and acquiring actual count CPM and actual measured light intensity data of a silicon photodiode of the series of standard color quenching samples in unit time through a photomultiplier, wherein the number of the series of samples is at least 5;
step three, a measuring step, namely arranging a sample to be measured of unknown DPM on a sample bearing unit, keeping a light intensity standard lamp closed, measuring a TDCR value and a CPM value, turning on the light intensity standard lamp, and measuring light intensity data by using a silicon photodiode;
step four, calculating, namely, making a ratio of the CPM value in the step one to the DPM value of the corresponding standard sample, and fitting the obtained ratio and the corresponding TDCR value to obtain a fitting curve of standard quenching counting efficiency and TDCR; and (3) making a ratio of the CPM value in the step two to the DPM value of the corresponding standard color quenching sample, fitting the obtained ratio and the corresponding light intensity value to obtain a color quenching counting efficiency and light intensity fitting curve, substituting the light intensity data in the step three into the color quenching counting efficiency and light intensity fitting curve to obtain the color quenching counting efficiency, substituting the TDCR value in the step three into the standard quenching counting efficiency and TDCR fitting curve to obtain the standard quenching counting efficiency, and dividing the CPM value of the sample to be measured in the
The series of standard color quenching samples are prepared by using acetone saturated liquid of methyl red as a color quencher and adding the color quencher with different volumes, and the preparation method belongs to a common preparation method in the field and can be obtained by a conventional preparation method, and is not described again;
in order to verify the effect of the invention, the following comparison method is designed:
the method for comparison is that the standard solution is measured by a traditional method and the method of the invention respectively, the standard value of the used standard solution is 525700 times/min, the standard solution is also used when necessary, the standard deviation of the result obtained by measuring 10 groups of data by the traditional method is 0.55-0.72%, the deviation between the measured average value and the standard value is about 0.85%, the standard deviation of the method of the invention is less than 0.52%, and the deviation between the average value and the standard value is less than 0.33%, so that the precision is better than that of the prior art.
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.
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