CN109324340B - Method for measuring radium concentration in water in open loop mode through total counting of Po-218 and Po-214 - Google Patents
Method for measuring radium concentration in water in open loop mode through total counting of Po-218 and Po-214 Download PDFInfo
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- CN109324340B CN109324340B CN201811377774.0A CN201811377774A CN109324340B CN 109324340 B CN109324340 B CN 109324340B CN 201811377774 A CN201811377774 A CN 201811377774A CN 109324340 B CN109324340 B CN 109324340B
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- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
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Abstract
In the measuring device, an air inlet pipe sleeve and an air outlet pipe sleeve are respectively arranged on a bottle cover, an air inlet pipe is inserted on the air inlet pipe sleeve, an air outlet pipe is inserted on the air outlet pipe sleeve, the air outlet pipe is connected with an air inlet end of an air pump, an air outlet end of the air pump is connected with an air inlet end of a three-way electromagnetic valve, a first air outlet end of the three-way electromagnetic valve is connected with an air inlet end of an electrostatic collection radon measuring instrument, a second air outlet end of the three-way electromagnetic valve is communicated with the atmospheric environment, and an air outlet end of the electrostatic collection radon measuring instrument is connected with a flowmeter. During measurement, the measuring device is placed in a constant-temperature environment, the air pump controls air to enter the water sample to be measured to bubble so as to carry out radon in the water sample to be measured, the air pump then enters the electrostatic collection method radon measuring instrument, and the radium concentration in water is calculated according to the ambient temperature, the volume of the water sample to be measured, the flow rate of the air pump, the reading of the electrostatic collection method radon measuring instrument, Po-218 decay counting and Po-214 decay counting.
Description
Technical Field
The invention relates to a nuclear radiation detection technology, in particular to a method for measuring radium concentration in water in an open-loop mode through total counting of Po-218 and Po-214.
Background
Radium (Ra-226) is an extremely toxic osteogenic alpha radionuclide, and its massive deposition in vivo can induce bone cancer or leukemia, thus endangering human health. Radium (Ra-226) has generally higher activity in underground water, and is 1-2 orders of magnitude higher than that of general surface water (river water, lake water, seawater and the like); drinking water sources in many regions in the world are groundwater, and the groundwater in some regions naturally contains high-concentration radium elements or a large amount of radium elements are activated and released into the groundwater along with the exploitation of different mineral products such as uranium mines and the like, so that great potential safety hazards exist when people use the groundwater as the drinking water source, and the concentration of the radium elements contained in the local groundwater needs to be monitored for a long time when the drinking water source is selected. The measuring device and the measuring method for the radium element concentration in water in the prior art are complex and long in measuring time, and a device and a method capable of rapidly measuring the radium element concentration in water are needed.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a method for measuring the radium concentration in water in an open loop manner by using the Po-218 and Po-214 total counting, and the device for measuring the radium concentration in water in an open loop manner by using the Po-218 and Po-214 total counting can quickly obtain the accurate radium concentration in water by using the method.
The technical scheme of the invention is as follows: the method for measuring the radium concentration in the water in an open loop manner by utilizing the device for measuring the radium concentration in the water in an open loop manner by utilizing the total counting numbers Po-218 and Po-214 comprises a measuring process and a calculating process, and the specific steps are as follows:
the device for measuring the radium concentration in water in an open-loop manner by using the Po-218 and Po-214 total counting comprises a water sample measuring bottle, a bottle cap, an air inlet pipe sleeve, an air outlet pipe sleeve, an air inlet pipe, an air outlet pipe, an air pump, a radon measuring instrument by using an electrostatic collection method, a flowmeter and a three-way electromagnetic valve.
The air inlet pipe sleeve and the air outlet pipe sleeve are respectively arranged on the bottle cap, the air inlet pipe is inserted on the air inlet pipe sleeve, the air outlet pipe is inserted on the air outlet pipe sleeve, the air outlet pipe is connected with the air inlet end of the air pump through a hose, the air outlet end of the air pump is connected with the air inlet end of the three-way electromagnetic valve through a hose, the first air outlet end of the three-way electromagnetic valve is connected with the air inlet end of the electrostatic collection method radon measuring instrument through a hose, the second air outlet end of the three-way electromagnetic valve is communicated with the atmospheric environment, and the air outlet end of the electrostatic collection method radon measuring instrument is connected with the flowmeter through a hose.
First, measuring process
A. Placing a device for measuring the radium concentration in water in an open-loop mode through total counting of Po-218 and Po-214 in a constant-temperature environment, and measuring the environment temperature;
B. pouring a water sample to be detected into the water sample measuring bottle, tightly covering the bottle cap, wherein the air outlet of the air inlet pipe is positioned in the water sample to be detected and close to the bottle bottom of the water sample measuring bottle, and the air inlet of the air outlet pipe is positioned on the liquid level of the water sample to be detected;
C. opening a second air outlet end of the three-way electromagnetic valve, closing a first air outlet end of the three-way electromagnetic valve, starting the air pump, controlling the flow rate of the air pump, enabling air to enter a water sample to be tested for bubbling through the air inlet pipe, simultaneously carrying out radon in the water sample to be tested, entering the three-way electromagnetic valve through the air outlet pipe, and then entering an atmospheric environment from the second air outlet end of the three-way electromagnetic valve, wherein the radon concentration in the air path can be considered to be 0 after the air pump is started for 5-30 minutes due to the very large flow rate of the air pump;
D. closing a second air outlet end of the three-way electromagnetic valve, opening a first air outlet end of the three-way electromagnetic valve, controlling the air pump to reduce the flow rate by acquiring the reading of the flow meter, so that air enters the water sample to be tested through the air inlet pipe to be bubbled, simultaneously carrying out radon in the water sample to be tested, enters the three-way electromagnetic valve through the air outlet pipe, enters the electrostatic collection radon measuring instrument from the first air outlet end of the three-way electromagnetic valve, and then enters the atmospheric environment through the flow meter; when the flow rate of the air pump is reduced, the flow rate of the air pump is kept moderate, so that the radon concentration in the measuring cavity of the electrostatic collection method radon measuring instrument and the gaseous radon concentration in the water sample measuring bottle synchronously change.
Second, calculating process
And calculating radium concentration in the water sample according to the ambient temperature, the volume of the water sample to be measured, the flow rate of the air pump and the reading of the electrostatic collection radon detector.
The radon in the water sample measuring bottle comes from the decay of the radium in the water. Setting the volume of the water sample as V and the radium activity in the water as ARaAnd then the radium concentration in water is CRaComprises the following steps:
CRa＝ARa/V (1)
water sample measurement bottle for measuring radon concentration C 'in water'RnThe change rule is as follows:
dC'Rn/dt＝CRaλRn-LCRn/V (2)
in the formula ofRnIs the decay constant, C, of radonRnThe radon concentration in the open-loop gas path water sample measuring bottle is measured, and L is the flow rate of the air pump.
According to the temperature during measurement, the concentration ratio X of radon in a water sample to gaseous radon during balance is obtained by looking up a table, and the method comprises the following steps:
C'Rn(t)＝XCRn(t) (3)
substituting formula (3) into formula (2) to obtain:
the solution of equation (4) is:
because the flow rate of the air pump is moderate, the radon concentration in the measuring cavity of the electrostatic collection method radon measuring instrument and the gaseous radon concentration in the water sample measuring bottle can be considered to be changed synchronously. According to the principle of the electrostatic collection radon measuring instrument, the change rule of the concentration of Po-218 in the measuring cavity is as follows:
in the formula CPo(t) is the Po-218 concentration in the measuring cavity of the radon measuring instrument by the electrostatic collection method, lambdaPoIs the Po-218 decay constant. The initial value of radon concentration in the measuring cavity of the electrostatic collection radon measuring instrument is 0, and the initial value of Po-218 concentration in the measuring cavity is also 0.
Substituting formula (5) for formula (6) to obtain:
the solution of equation (7) is:
the formula (8) is the change rule of the Po-218 concentration in the measurement cavity of the radon measuring instrument by the electrostatic collection method.
Measuring a longer period T, which is 20-200 minutes, equation (8) can be changed to:
integration over the interval (0, T) for equation (7) yields:
according to the principle of an electrostatic collection radon measuring instrument, reading C in a certain measuring periodnThe average Po-218 concentration for this cycle is:
equation (10) can be varied as:
equation (9) minus equation (12) yields:
when the value of T is large, the value of T,
and
is very small, equation (13) can be simplified to:
the radium concentration in water was calculated by using the measured value of a longer measurement period according to equation (13) or (14).
According to radon decay chain, the following components are obtained in a measuring cavity:
in the formula CPb(t)、CBi(t) the concentrations of Pb-214 and Bi-214, respectively; lambdaPb、λBiThe decay constants of Pb-214 and Bi-214, respectively; after Bi-214 decays to Po-214, the half life of the Po-214 is 164us, and the concentration of Bi-214 can be considered as the concentration of the Po-214, namely:
CPo214(t) is the concentration of Po-214.
The formula (8) is solved by substituting the formula (15):
substituting formula (18) for formula (17) to obtain:
when T is T, formula (19) changes to:
integration of equation (17) over the (0, T) interval yields:
the electrostatic collection emanometer counts the number of alpha particles released by radioactive decay of Po-218 and Po-214. The detector of the electrostatic collection radon detector has basically the same detection efficiency for the two alpha particles with different energies. The decay counts Po-218 and Po-214 measured in the measurement period T are respectively n1、n2。
Further according to formula (11) there are:
by substituting formulae (18), (22) for formula (21)
The formula (20) is reduced by the formula (23):
when the value of T is large, the value of T,
is very small, equation (24) reduces to:
calculating the radium concentration in the water by using the measured Po-214 decay count and a measured value with a longer measuring period according to the formula (24) or (25);
respectively calculating radium concentration in water by using the radioactive decay measurement values Po-218 and Po-214 with a longer measurement period according to the formulas (13) and (24), and then calculating the average value of the radium concentration values in the two water to obtain more accurate radium concentration in the water.
Or respectively calculating radium concentration in water by using the radioactive decay measurement values Po-218 and Po-214 with a longer measurement period according to the formulas (14) and (25), and then calculating the average value of the radium concentration values in the two water to obtain more accurate radium concentration in the water.
Compared with the prior art, the invention has the following advantages:
1. the device for measuring the radium concentration in water in an open-loop manner by using the total counting numbers Po-218 and Po-214 is simple in structure, convenient to operate and short in measuring time.
2. The method for measuring radium concentration in water in an open-loop manner by using the Po-218 and Po-214 total counting is simple in calculation process of radium concentration in water, the obtained radium concentration result is accurate, a healthy drinking water standard can be established for the country by carrying out long-term continuous monitoring and analysis on radium concentration in a groundwater sample in a certain area, a basis is provided for water pollution treatment, national disease prevention and treatment, farming and animal husbandry water and the like, and the groundwater environment and drinking water safety of residents is ensured.
The detailed structure of the invention is further described below in conjunction with the drawings and the detailed description.
Drawings
FIG. 1 is a schematic structural diagram of an apparatus for measuring radium concentration in water in an open-loop manner with total counting numbers Po-218 and Po-214 according to the present invention.
Detailed Description
As shown in fig. 1, the device for measuring radium concentration in water in an open-loop manner by total counting of Po-218 and Po-214 comprises a water sample measuring bottle 1, a bottle cap 2, an air inlet pipe sleeve 3, an air outlet pipe sleeve 4, an air inlet pipe 5, an air outlet pipe 6, an air pump 7, an electrostatic collection radon measuring instrument 8, a flowmeter 9 and a three-way electromagnetic valve 10;
an air inlet pipe sleeve 3 and an air outlet pipe sleeve 4 are respectively arranged on a bottle cap 2, an air inlet pipe 5 is inserted on the air inlet pipe sleeve 3, an air outlet pipe 6 is inserted on the air outlet pipe sleeve 4, the air outlet pipe 6 is connected with an air inlet end of an air pump 7 through a hose, an air outlet end of the air pump 7 is connected with an air inlet end of a three-way electromagnetic valve 10 through a hose, a first air outlet end of the three-way electromagnetic valve 10 is connected with an air inlet end of an electrostatic collection method radon measuring instrument 8 through a hose, a second air outlet end of the three-way electromagnetic valve 10 is communicated with the atmospheric environment, and an air outlet end of the electrostatic collection method radon measuring instrument 8 is connected with a flowmeter 9 through a hose.
The method for carrying out Po-218 and Po-214 total counting open-loop measurement on radium concentration in water by adopting the measuring device comprises a measuring process and a calculating process, and comprises the following specific steps:
first, measuring process
A. Placing a device for measuring the radium concentration in water in an open-loop mode through total counting of Po-218 and Po-214 in a constant-temperature environment, and measuring the environment temperature;
B. pouring a water sample to be detected into the water sample measuring bottle 1, tightly covering the bottle cap 2, enabling the air outlet of the air inlet pipe 5 to be positioned in the water sample to be detected and close to the bottle bottom of the water sample measuring bottle 1, and enabling the air inlet of the air outlet pipe 6 to be positioned on the liquid level of the water sample to be detected;
C. opening a second air outlet end of the three-way electromagnetic valve 10, closing a first air outlet end of the three-way electromagnetic valve 10, starting the air pump 7, controlling the flow rate of the air pump 7, enabling air to enter the water sample to be tested for bubbling through the air inlet pipe 5, simultaneously carrying out radon in the water sample to be tested out, entering the air pump 7 through the air outlet pipe 6, entering the three-way electromagnetic valve 10, and then entering an atmospheric environment from the second air outlet end of the three-way electromagnetic valve 10, wherein the radon concentration in the air path can be considered to be 0 after the air pump is started for 5-30 minutes due to the very high flow rate of the air pump;
D. closing a second air outlet end of the three-way electromagnetic valve 10, opening a first air outlet end of the three-way electromagnetic valve 10, controlling the air pump 7 to regulate the flow rate to be small by obtaining the reading of the flowmeter 9, so that air enters the water sample to be tested through the air inlet pipe 5 to be bubbled, and simultaneously carrying out radon in the water sample to be tested, enters the three-way electromagnetic valve 10 through the air outlet pipe 6 and enters the air pump 7, and then enters the electrostatic collection method radon measuring instrument 8 from the first air outlet end of the three-way electromagnetic valve 10 and then enters the atmospheric environment through the flowmeter 9; when the flow rate of the air pump 7 is reduced, the flow rate of the air pump 7 is kept moderate, so that the radon concentration in the measuring cavity of the electrostatic collection radon measuring instrument 8 and the gaseous radon concentration in the water sample measuring bottle 1 synchronously change.
Second, calculating process
The radon in the water sampling bottle 1 originates from the decay of radium in the water. The volume of the water sample is V, and the radium activity in the water is ARaAnd then the radium concentration in water is CRaComprises the following steps:
CRa＝ARa/V (1)
water sample measurement bottle 1 for measuring radon concentration C 'in water'RnThe change rule of (2) is as follows:
dC'Rn/dt＝CRaλRn-LCRn/V (2)
in the formula ofRnIs the decay constant, C, of radonRnThe radon concentration in the open-loop gas path water sample measuring bottle, and L is the flow rate of the air pump 7.
According to the temperature during measurement, the concentration ratio X of radon in a water sample to gaseous radon during balance is obtained by looking up a table, and the method comprises the following steps:
C'Rn(t)＝XCRn(t) (3)
substituting formula (3) into formula (2) to obtain:
the solution of equation (4) is:
because the flow rate of the air pump 7 is moderate, the radon concentration in the measuring cavity of the electrostatic collection method radon measuring instrument 8 and the gaseous radon concentration in the water sample measuring bottle 1 can be considered to be changed synchronously. According to the principle of the electrostatic collection radon measuring instrument 8, the change rule of the concentration of Po-218 in the measurement cavity is as follows:
in the formula CPo(t) is the concentration of Po-218 in the measuring cavity of the radon measuring instrument 8 by the electrostatic collection method, lambdaPoIs the Po-218 decay constant. The initial value of the radon concentration in the measurement cavity of the electrostatic collection radon measuring instrument 8 is 0, and the initial value of the Po-218 concentration in the measurement cavity is also 0.
Substituting formula (5) for formula (6) to obtain:
the solution of equation (7) is:
the formula (8) is the change rule of the Po-218 concentration in the measurement cavity of the radon detector 8 by the electrostatic collection method.
Measuring a longer period T, which is 20-200 minutes, equation (8) can be changed to:
integration of equation (7) over the (0, T) interval yields:
according to the principle of an electrostatic collection radon measuring instrument 8, reading C in a certain measuring periodnThe average Po-218 concentration for this cycle is:
equation (10) can be varied as:
equation (12) is subtracted from equation (9) to yield:
when the value of T is large, the value of T,
and
is very small, equation (13) can be simplified to:
and (5) calculating the radium concentration in the water by using the measured value of a longer measuring period according to the formula (13) or (14).
According to radon decay chain, the radon measuring instrument has the following components in a measuring cavity:
in the formula CPb(t)、CBi(t) the concentrations of Pb-214 and Bi-214, respectively; lambdaPb、λBiThe decay constants of Pb-214 and Bi-214, respectively; after Bi-214 decays to Po-214, the half life of the Po-214 is 164us, and the concentration of Bi-214 can be considered as the concentration of the Po-214, namely:
CPo214(t) is the concentration of Po-214.
Substituting formula (8) for formula (15) to obtain:
formula (18) is solved by substituting formula (17):
when T is T, equation (19) changes to:
integration of equation (17) over the (0, T) interval yields:
the electrostatic collection emanometer counts the number of alpha particles released by radioactive decay of Po-218 and Po-214. The detector of the electrostatic collection radon detector has basically the same detection efficiency for the two alpha particles with different energies. The decay counts Po-218 and Po-214 measured in the measurement period T are respectively n1、n2。
Further according to formula (11) there are:
by substituting the formulae (18) and (22) for the formula (21)
The formula (20) is reduced by the formula (23):
when the value of T is large, the value of T,
is very small, equation (24) reduces to:
calculating the radium concentration in the water by using the measured Po-214 decay count and a measured value with a longer measuring period according to the formula (24) or (25);
respectively calculating radium concentration in water by using Po-218 and Po-214 radioactive decay measured values with a longer measuring period according to formulas (13) and (24), and then calculating an average value of radium concentration values in the two water to obtain more accurate radium concentration in the water.
Or respectively calculating radium concentration in the water by using the Po-218 and Po-214 radioactive decay measured values with a longer measuring period according to the formulas (14) and (25), and then calculating the average value of the radium concentration values in the two water to obtain more accurate radium concentration in the water.
Claims (1)
1. The method for measuring the radium concentration in the water in an open loop manner by utilizing the device for measuring the radium concentration in the water in an open loop manner by utilizing the total counting numbers of Po-218 and Po-214 is characterized by comprising a measuring process and a calculating process, and the method comprises the following specific steps:
the device for measuring the radium concentration in water in an open-loop manner by using the total counting number Po-218 and Po-214 comprises a water sample measuring bottle, a bottle cap, an air inlet pipe sleeve, an air outlet pipe sleeve, an air inlet pipe, an air outlet pipe, an air pump, a static collecting radon measuring instrument, a flowmeter and a three-way electromagnetic valve;
the air inlet pipe sleeve and the air outlet pipe sleeve are respectively arranged on the bottle cap, the air inlet pipe is inserted on the air inlet pipe sleeve, the air outlet pipe is inserted on the air outlet pipe sleeve, the air outlet pipe is connected with the air inlet end of the air pump through a hose, the air outlet end of the air pump is connected with the air inlet end of the three-way electromagnetic valve through a hose, the first air outlet end of the three-way electromagnetic valve is connected with the air inlet end of the electrostatic collection method radon measuring instrument through a hose, the second air outlet end of the three-way electromagnetic valve is communicated with the atmospheric environment, and the air outlet end of the electrostatic collection method radon measuring instrument is connected with the flowmeter through a hose;
first, measurement process
A. Placing a device for measuring the radium concentration in the water in an open-loop mode by using the total counting numbers Po-218 and Po-214 in a constant-temperature environment, and measuring the environment temperature;
B. pouring a water sample to be detected into the water sample measuring bottle, tightly covering the bottle cap, wherein the air outlet of the air inlet pipe is positioned in the water sample to be detected and close to the bottle bottom of the water sample measuring bottle, and the air inlet of the air outlet pipe is positioned on the liquid level of the water sample to be detected;
C. opening a second air outlet end of the three-way electromagnetic valve, closing a first air outlet end of the three-way electromagnetic valve, starting the air pump, controlling the flow rate of the air pump, enabling air to enter a water sample to be tested for bubbling through the air inlet pipe, simultaneously carrying out radon in the water sample to be tested, entering the three-way electromagnetic valve through the air outlet pipe, and then entering an atmospheric environment from the second air outlet end of the three-way electromagnetic valve, wherein the radon concentration in the air path can be considered to be 0 after the air pump is started for 5-30 minutes due to the very large flow rate of the air pump;
D. closing a second air outlet end of the three-way electromagnetic valve, opening a first air outlet end of the three-way electromagnetic valve, controlling the air pump to reduce the flow rate by acquiring the reading of the flowmeter, so that air enters the water sample to be tested through the air inlet pipe to be bubbled, simultaneously carrying out radon in the water sample to be tested, enters the three-way electromagnetic valve through the air outlet pipe, enters the electrostatic collection method radon detector from the first air outlet end of the three-way electromagnetic valve, and then enters the atmospheric environment through the flowmeter; when the flow rate of the air pump is reduced, the flow rate of the air pump is kept moderate, so that the radon concentration in the measuring cavity of the electrostatic collection radon measuring instrument and the gaseous radon concentration in the water sample measuring bottle synchronously change;
second, calculating process
Calculating radium concentration in the water sample according to the environment temperature, the volume of the water sample to be measured, the flow rate of the air pump and the reading of the static collection radon measuring instrument;
the radon in the water sample measuring bottle comes from the decay of the radium in the water, the volume of the water sample is V, and the activity of the radium in the water is ARaAnd then the radium concentration in water is CRaComprises the following steps:
CRa＝ARa/V (1)
water sample measurement bottle for measuring radon concentration C 'in water'RnThe change rule is as follows:
dC'Rn/dt＝CRaλRn-LCRn/V (2)
in the formula ofRnIs the decay constant, C, of radonRnThe radon concentration in the open-loop gas path water sample measuring bottle is measured, and L is the flow rate of the gas pump;
according to the temperature during measurement, the concentration ratio X of radon in a water sample to gaseous radon during balance is obtained by looking up a table, and the method comprises the following steps:
C'Rn(t)＝XCRn(t) (3)
substituting formula (3) into formula (2) to obtain:
the solution of equation (4) is:
because the flow rate of the air pump is moderate, the radon concentration in the measuring cavity of the electrostatic collection method radon measuring instrument and the gaseous radon concentration in the water sample measuring bottle can be considered to be changed synchronously; according to the principle of the electrostatic collection radon detector, the change rule of the Po-218 concentration in the measurement cavity is as follows:
in the formula CPo(t) Po-218 concentration in the measuring cavity of the radon measuring instrument by using an electrostatic collection method, lambdaPoIs the Po-218 decay constant; the initial value of radon concentration in a measuring cavity of the electrostatic collection radon measuring instrument is 0, and the initial value of Po-218 concentration in the measuring cavity is also 0;
substituting formula (5) for formula (6) to obtain:
the solution of equation (7) is:
the formula (8) is the change rule of Po-218 concentration in a measurement cavity of the radon detector by using the electrostatic collection method;
measuring a longer period T, which is 20-200 minutes, equation (8) can be changed to:
integration over the interval (0, T) for equation (7) yields:
according to the principle of an electrostatic collection radon measuring instrument, reading C in a certain measuring periodnThe average Po-218 concentration for this cycle is:
equation (10) can be varied as:
equation (12) is subtracted from equation (9) to yield:
when the value of T is large, the value of T,
and
is very small, equation (13) can be simplified to:
calculating radium concentration in water by using a measurement value of a longer measurement period according to the formula (13) or (14);
according to radon decay chain, the following components are obtained in a measuring cavity:
in the formula CPb(t)、CBi(t) the concentrations of Pb-214 and Bi-214, respectively; lambda [ alpha ]Pb、λBiThe decay constants of Pb-214 and Bi-214, respectively; after Bi-214 decays to Po-214,the half-life of Po-214 is 164us, and the concentration of Bi-214 can be considered as the concentration of Po-214, namely:
CPo214(t) is the concentration of Po-214;
the formula (8) is solved by substituting the formula (15):
substituting formula (18) for formula (17) to obtain:
when T is T, equation (19) changes to:
integrating equation (17) over the interval (0, T) yields:
the electrostatic collection radon measuring instrument respectively counts according to different energies of alpha particles released by radioactive decay of Po-218 and Po-214, the detector of the electrostatic collection radon measuring instrument basically has the same detection efficiency on the two alpha particles with different energies, and decay counts of Po-218 and Po-214 respectively are n measured in a measurement period T1、n2；
Further according to formula (11) there are:
by substituting formulae (18), (22) for formula (21)
The formula (20) is reduced by the formula (23):
when the value of T is large, the value of T,
is very small, equation (24) reduces to:
calculating radium concentration in water by using the measured Po-214 decay count and a measured value of a longer measuring period according to the formula (24) or (25);
respectively calculating radium concentration in water by using Po-218 and Po-214 radioactive decay measured values with a longer measuring period according to formulas (13) and (24), and calculating an average value of radium concentration values in the two water to obtain more accurate radium concentration in the water;
or respectively calculating radium concentration in the water by using the Po-218 and Po-214 radioactive decay measured values with a longer measuring period according to the formulas (14) and (25), and then calculating the average value of the radium concentration values in the two water to obtain more accurate radium concentration in the water.
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| CN109212580B (en) * | 2018-11-19 | 2022-07-19 | 衡阳师范学院 | Method for measuring radium concentration in water by open-loop type electrostatic collection two-stage method |
| CN109212581B (en) * | 2018-11-19 | 2022-07-22 | 衡阳师范学院 | Method for measuring radium concentration in water in open-loop type single cycle mode |
| CN109188493B (en) * | 2018-11-19 | 2022-06-07 | 衡阳师范学院 | Open-loop method for rapidly measuring radium concentration in water |
| CN109188494B (en) * | 2018-11-21 | 2022-06-21 | 衡阳师范学院 | Method for partially integrating and measuring radium concentration in water by open-loop electrostatic collection method |
| CN109188496B (en) * | 2018-11-21 | 2022-06-21 | 衡阳师范学院 | Method for measuring effective decay constant and radium concentration in water by open-loop electrostatic collection method |
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| CN102109452B (en) * | 2011-01-21 | 2012-07-04 | 衡阳师范学院 | Method for measuring radon separation rate in adaptive open loop way |
| KR101280235B1 (en) * | 2011-11-06 | 2013-07-05 | 박영웅 | Simplified Method for Measurement of Radium in the Underground Water |
| CN102426379B (en) * | 2011-11-18 | 2013-06-19 | 衡阳师范学院 | Method for measuring radon emanation rate by adopting two-stage method |
| CN102830418B (en) * | 2012-08-30 | 2014-12-10 | 衡阳师范学院 | Method for open-loop measurement of radon exhalation rate by utilizing total count of 218Po and 214Po |
| KR101682161B1 (en) * | 2013-12-20 | 2016-12-02 | 주식회사 오리온이엔씨 | System for automatically on-line monitering radon in water |
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| CN105158788B (en) * | 2015-09-30 | 2018-02-27 | 衡阳师范学院 | The method of open loop type synchro measure Effective Decay Constant and precipitation rate of radon |
| CN109212580B (en) * | 2018-11-19 | 2022-07-19 | 衡阳师范学院 | Method for measuring radium concentration in water by open-loop type electrostatic collection two-stage method |
| CN109212581B (en) * | 2018-11-19 | 2022-07-22 | 衡阳师范学院 | Method for measuring radium concentration in water in open-loop type single cycle mode |
| CN109188493B (en) * | 2018-11-19 | 2022-06-07 | 衡阳师范学院 | Open-loop method for rapidly measuring radium concentration in water |
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