CN103197336B - Method for rapidly measuring 222Rn and 220Rn daughter concentration in air in terms of alpha general count - Google Patents
Method for rapidly measuring 222Rn and 220Rn daughter concentration in air in terms of alpha general count Download PDFInfo
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Abstract
The invention relates to a method for rapidly measuring 222Rn and 220Rn daughter concentration in air in terms of an alpha general count. An air sampling pump is utilized to collect radon daughters in the air to a filtering membrane, an alpha disintegration total count on the filtering membrane is measured, and therefore air concentration of the radon daughters is calculated. Two kinds of measuring periods exist, namely a short-time interval measuring period and a long-time interval measuring period. When a short-time interval t is taken as the measuring period, data larger or equal to six measuring periods are utilized and nonlinear fitting or the least square method is utilized so as to obtain 222Rn and 220Rn daughter activity on the filtering membrane at the beginning measurement. When long-time intervals, namely t1, t2, t3, t4, t5 and t6 are taken as measuring periods which are 6 in number, the 222Rn and 220Rn daughter activity on the filtering membrane at the beginning measurement can also be obtained. The radioactive decay law and the accumulation law of the 222Rn and 220Rn daughters on the filtering membrane in the sampling process are utilized, and therefore the 222Rn and 220Rn daughter concentration in the air can be obtained in a backstepping mode.
Description
Technical field
The present invention relates to a kind of nuclear radiation detection technology, particularly one utilizes total α to count in Quick Measurement air
222rn,
220the method of Rn daughter concentration.
Background technology
In recent years, along with people couple
222rn,
220what Rn and daughter thereof were studied gos deep into, and finds in the environment had
220rn and daughter Dosage be can not ignore and it is right
222rn and daughter measurement thereof cause interference.Due to
222rn,
220the radiation dose of the decay daughter of Rn far away higher than radon itself, in addition
220the equilibrium relation of Rn and daughter thereof in time, place be change, only basis
222rn,
220the measurement result of Rn level is estimated
222rn,
220the dosage that Rn and daughter thereof produce is inadequate.In order to evaluate more exactly
222rn,
220the harm of Rn, be necessary to 222Rn in surrounding air,
220the level of Rn daughter is measured simultaneously.Measured in the past simultaneously
222rn,
220the method of Rn Level of radons daughters mainly contains three-stage process and five sections of methods, and this type of measuring method belongs to total α method, or Measuring Time is longer, or measuring error is larger.The advantage of the energy of alpha energy spectrum method differentiation in recent years exists
222rn and
220rn Level of radons daughters obtains utilization in measuring, and achieves in air
222rn and
220rn Level of radons daughters is quick, reliable measurements.But energy spectrometer is expensive, and the drift of the road of multi-channel energy spectrometer is inevitable.
Summary of the invention
The object of the invention is to overcome the above-mentioned deficiency of prior art and a kind of basis is provided
222rn,
220rn daughter activity decay characteristic, after sampling
222rn,
220the time dependent rule of radiogenic high-energyα-particle tale of Rn daughter sample is measured, and applies two kinds of different measuring methods and obtains
222rn,
220rn daughter concentration.
Technical scheme of the present invention is: one utilizes in α particle total-count measurement air
222rn,
220the method of Rn daughter, the easiest and the Radon daughter sampling of practicability and effectiveness and measuring process, be adopt air sampling pump to collect on filter membrane by Radon daughter, then measure the alpha-decay tale on filter membrane, thus calculate radon daughter air concentration.
?
222in Rn daughter disintegration chain, have dosimeter meaning be RaA (
218po), RaB (
214pb), RaC (
214bi), due to RaC ' (
214po) half life period is very short, only has 164 μ s, therefore the radioactivity of RaC ' is summed up as the radioactivity of RaC; ?
220in Rn daughter disintegration chain, have dosimeter meaning be ThB (
212pb), ThC (
212bi), by ThC ' (
212po), ThC ' ' (
208tl) radioactivity be summed up as ThC (
212bi) radioactivity.
This measuring method is based on following condition:
1) in sampling process
222rn,
220rn daughter concentration and air sampling pump sampling flow rate invariable;
2) filtration efficiency of filter membrane and the self-absorption factor are constant constant, and disobey gasoloid particle diameter and change, and when using miillpore filter, do not have self-absorption;
3) detection efficiency of detector is constant constant, and disobey alpha-particle energy change, depend on filter membrane there is less self-absorption and filter membrane less to detector distance.
?
222rn,
220in Rn daughter sampling process, the radon daughter quantity on filter membrane constantly increases along with sampling, and its quantity also because from parent nuclide decay, increase decays with self and reduces, can be stated by following differential equation group:
In formula, G is filtration efficiency, and Q is sampling flow rate, C
raA, C
raBc
raC, C
thB, C
thCbe respectively RaA, RaB, RaC, ThB, ThC activity concentration, λ, λ
raBλ
raC, λ
thB, λ
thCbe respectively the half life period of RaA, RaB, RaC, ThB, ThC, N
raA, N
raBn
raC, N
thB, N
thCbe respectively the atomicity of RaA, RaB, RaC, ThB, the ThC in sampling process, filter membrane accumulated.
Formula (1) is solved and can be obtained: sampling time T
1at the end of the relation of RaA, RaB, RaC, ThB, ThC activity concentration in the atomicity of RaA, RaB, RaC, ThB, ThC that filter membrane accumulates and air.
After sampling terminates, take off filter membrane feeding α count measurement instrument and measure, this time interval is T
2, on filter membrane
222rn,
220rn daughter is with the quantity of finish time of sampling for initial value starts decay, and daughter nuclide also increases due to the decay of parent nuclide simultaneously, states by following differential equation group:
To formula (2) solve obtain sampling terminate after through T
2time decays, the atomicity of RaA, RaB, RaC, ThB, ThC on filter membrane and the relation of the atomicity of RaA, RaB, RaC, ThB, ThC of sampling finish time.
Utilize α count measurement instrument to start to measure moment to filter membrane, the atomicity of RaA, RaB, RaC, ThB, ThC on filter membrane is respectively N
raA1, N
raB1n
raC1, N
thB1, N
thC1, to retrodict RaA, RaB, RaC, ThB, ThC activity concentration obtained in air according to formula (1), (2).
After sampling, filter membrane is sent into α count measurement instrument, start to measure total α and count.
222the alpha-decay of Rn daughter comprises: RaA (
218po) 6.0MeV, RaC` (
214po) 7.69MeV;
220the alpha-decay of Rn daughter comprises: ThC (
212bi) 6.05MeV, ThC` (
212po) 8.78MeV.
After α count measurement instrument starts measurement, on filter membrane
222rn,
220rn daughter is still by formula (2) decay, and solve formula (2), the atomicity solving RaA, RaB, RaC, ThB, the ThC of any time on filter membrane in measuring process is:
Formula (3), (4), (5), (6), (7) are converted to activity form:
The activity of RaA, RaB, RaC, ThB, ThC on filter membrane is respectively A
raA, A
raBa
raC, A
thB, A
thC.
According to
222rn,
220rn Law of radioactive decay is known, total alpha-decay activity A of any time on filter membrane
α(t) be:
A
α(t)=A
RaA(t)+A
RaC(t)+A
ThC(t)+A
0（13）
A in formula
0for the background counting rate of α count measurement instrument.
α count measurement instrument has two kinds measuring period, is divided into short time interval measurement cycle and long-time interval measurement cycle:
One, with short time interval t for measuring period, time t is 1-10 minute, and amount of cycles is more than or equal to 6.
Its computing method have two kinds:
A, count n (i) according to the total α of i-th measuring period, try to achieve the average counter of the unit interval of i-th measuring period, because measuring period is shorter, these average counters and A
αt (), in the value approximately equal of this of mid point, has measuring period:
E is that α count measurement instrument is to the detection efficiency of α particle.
Utilize formula (14) to carry out nonlinear fitting to the data of n (i)/t, can N be obtained
raA1, N
raB1n
raC1, N
thB1, N
thC1, A
0value; Then retrodict obtain RaA, RaB, RaC, ThB, ThC activity concentration in air according to formula (1), (2).
B, ask A
αt () is at the integration of i-th measuring period:
Application least square method solves
222rn,
220rn daughter concentration, introduce residual error R:
W in formula
ibe the weight factor that i counts section, the different error effect to fitting result of the counting statistics error of each counting section is considered in the introducing of weight factor.
According to principle of least square method, make residual error R get minimum value, can N be obtained
raA1, N
raB1n
raC1, N
thB1, N
thC1, A
0value, then retrodict obtain air RaA, RaB, RaC, ThB, ThC activity concentration according to formula (1), (2).
Two, with long time interval t
1, t
2, t
3, t
4, t
5, t
6for measuring period, time t
1, t
2, t
3, t
4, t
5, t
6be respectively 10-120 minute, measuring period is 6.
Its computing method are:
The counting of 6 measuring periods is respectively n (1), n (2), n (3), n (4), n (5), n (6).
By n (1), n (2), n (3), n (4), n (5), n (6) value brings formula (17), (18), (19), (20), (21), (22) into, solves N
raA1, N
raB1n
raC1, N
thB1, N
thC1, A
0the value of value, then retrodict obtain RaA, RaB, RaC, ThB, ThC activity concentration in air according to formula (1), (2).
This method adopts
222rn,
220rn daughter acquisition system forms by with the sampling head of filter membrane, thief rod, flowmeter, connecting pipe and air sampling pump, and sampling head is connected with thief rod, and thief rod is connected with flowmeter, and flowmeter is connected with air sampling pump by connecting pipe.
The present invention compared with prior art has following features:
First need not measure background counting rate, thus decrease Measuring Time, improve measuring accuracy, decrease measurement cost.
Below in conjunction with the drawings and specific embodiments, detailed construction of the present invention is further described.
Accompanying drawing explanation
Accompanying drawing is
222rn,
220rn daughter acquisition system schematic diagram.
Embodiment
Embodiment one, one utilize in α particle total-count measurement air
222rn,
220the method of Rn daughter, the present embodiment adopts
222rn,
220rn daughter acquisition system forms by with the sampling head 1 of filter membrane 6, thief rod 2, flowmeter 3, connecting pipe 4 and air sampling pump 5, and sampling head 1 is connected with thief rod 2, and thief rod 2 is connected with flowmeter 3, and flowmeter 3 is connected with air sampling pump 5 by connecting pipe 4.
By air sampling pump 5, Radon daughter is collected on filter membrane 6, then measure the alpha-decay tale on filter membrane 6, thus calculate radon daughter air concentration.
This measuring method is based on following condition:
1) in sampling process
222rn,
220rn daughter concentration and air sampling pump 5 flow rate of sampling is invariable;
2) filtration efficiency of filter membrane 6 and the self-absorption factor are constant constant, and disobey gasoloid particle diameter and change, and when using miillpore filter, do not have self-absorption;
3) detection efficiency of detector is constant constant, and disobeys alpha-particle energy and change, and depends on filter membrane 6 and has less self-absorption and filter membrane 6 is less to detector distance.
?
222rn,
220in Rn daughter sampling process, the radon daughter quantity on filter membrane 6 constantly increases along with sampling, and its quantity also because from parent nuclide decay, increase decays with self and reduces, can be stated by following differential equation group:
In formula, G is filtration efficiency, and Q is sampling flow rate, C
raA, C
raBc
raC, C, C
thCbe respectively RaA, RaB, RaC, ThB, ThC activity concentration, λ
raA, λ
raBλ
raC, λ
thB, λ
thCbe respectively the half life period of RaA, RaB, RaC, ThB, ThC, N
raA, N
raBn
raC, N
thB, N
thCbe respectively the atomicity of RaA, RaB, RaC, ThB, ThC of accumulation on filter membrane 6 in sampling process.
Formula (1) is solved and can be obtained: sampling time T
1at the end of the relation of RaA, RaB, RaC, ThB, ThC activity concentration in the atomicity of RaA, RaB, RaC, ThB, ThC of accumulation and air on filter membrane 6.
After sampling terminates, take off filter membrane 6 and send into α count measurement instrument and measure, this time interval is T
2, on filter membrane 6
222rn,
220rn daughter is with the quantity of finish time of sampling for initial value starts decay, and daughter nuclide also increases due to the decay of parent nuclide simultaneously, states by following differential equation group:
To formula (2) solve obtain sampling terminate after through T
2time decays, the atomicity of RaA, RaB, RaC, ThB, ThC on filter membrane 6 and the relation of the atomicity of RaA, RaB, RaC, ThB, ThC of sampling finish time.
Utilize α count measurement instrument to start to measure moment to filter membrane 6, the atomicity of RaA, RaB, RaC, ThB, ThC on filter membrane 6 is respectively N
raA1, N
raB1n
raC1, N
thB1, N
thC1, to retrodict RaA, RaB, RaC, ThB, ThC activity concentration obtained in air according to formula (1), (2).
After sampling, filter membrane 6 is sent into α count measurement instrument, start to measure total α and count.
222the alpha-decay of Rn daughter comprises: RaA (
218po) 6.0MeV, RaC` (
214po) 7.69MeV;
220the alpha-decay of Rn daughter comprises: ThC (
212bi) 6.05MeV, ThC` (
212po) 8.78MeV.
After α count measurement instrument starts measurement, on filter membrane 6
222rn,
220rn daughter is still by formula (2) decay, and solve formula (2), the atomicity solving RaA, RaB, RaC, ThB, the ThC of filter membrane 6 upper any time in measuring process is:
Formula (3), (4), (5), (6), (7) are converted to activity form:
The activity of RaA, RaB, RaC, ThB, ThC on filter membrane 6 is respectively A
raA, A
raBa
raC, A
thB, A
thC.
According to
222rn,
220rn Law of radioactive decay is known, total alpha-decay activity A of filter membrane 6 upper any time
α(t) be:
A
α(t)=A
RaA(t)+A
RaC(t)+A
ThC(t)+A
0（13）
A in formula
0for the background counting rate of α count measurement instrument.
With short time interval t for measuring period, time t is 1-10 minute, and amount of cycles is more than or equal to 6.
Its computing method have two kinds:
A, count n (i) according to the total α of i-th measuring period, try to achieve the average counter of the unit interval of i-th measuring period, because measuring period is shorter, these average counters and A
αt (), in the value approximately equal of this of mid point, has measuring period:
E is that α count measurement instrument is to the detection efficiency of α particle.
Utilize formula (14) to carry out nonlinear fitting to the data of n (i)/t, can N be obtained
raA1, N
raB1n
raC1, N
thB1, N
thC1, A
0value; Then retrodict obtain RaA, RaB, RaC, ThB, ThC activity concentration in air according to formula (1), (2).
B, ask A
αt () is at the integration of i-th measuring period:
Application least square method solves
222rn,
220rn daughter concentration, introduce residual error R:
W in formula
ibe the weight factor that i counts section, the different error effect to fitting result of the counting statistics error of each counting section is considered in the introducing of weight factor.
According to principle of least square method, make residual error R get minimum value, can N be obtained
raA1, N
raB1n
raC1, N
thB1, N
thC1, A
0value, then retrodict obtain air RaA, RaB, RaC, ThB, ThC activity concentration according to formula (1), (2).
Embodiment two, one utilize in α particle total-count measurement air
222rn,
220the method of Rn daughter, 222Rn, 220Rn daughter acquisition system that the present embodiment adopts forms by with the sampling head 1 of filter membrane 6, thief rod 2, flowmeter 3, connecting pipe 4 and air sampling pump 5, sampling head 1 is connected with thief rod 2, thief rod 2 is connected with flowmeter 3, and flowmeter 3 is connected with air sampling pump 5 by connecting pipe 4.
By air sampling pump 5, Radon daughter is collected on filter membrane 6, then measure the alpha-decay tale on filter membrane 6, thus calculate radon daughter air concentration.
This measuring method is based on following condition:
1) in sampling process
222rn,
220rn daughter concentration and air sampling pump 5 flow rate of sampling is invariable;
2) filtration efficiency of filter membrane 6 and the self-absorption factor are constant constant, and disobey gasoloid particle diameter and change, and when using miillpore filter, do not have self-absorption;
3) detection efficiency of detector is constant constant, and disobeys alpha-particle energy and change, and depends on filter membrane 6 and has less self-absorption and filter membrane 6 is less to detector distance.
?
222rn,
220in Rn daughter sampling process, the radon daughter quantity on filter membrane 6 constantly increases along with sampling, and its quantity also because from parent nuclide decay, increase decays with self and reduces, can be stated by following differential equation group:
In formula, G is filtration efficiency, and Q is sampling flow rate, C
raA, C
raBc
raC, C
thB, C
thCbe respectively RaA, RaB, RaC, ThB, ThC activity concentration, λ
raA, λ
raBλ
raC, λ
thB, λ
thCbe respectively the half life period of RaA, RaB, RaC, ThB, ThC, N
raA, N
raBn
raC, N
thB, N
thCbe respectively the atomicity of RaA, RaB, RaC, ThB, ThC of accumulation on filter membrane 6 in sampling process.
Formula (1) is solved and can be obtained: sampling time T
1at the end of the relation of RaA, RaB, RaC, ThB, ThC activity concentration in the atomicity of RaA, RaB, RaC, ThB, ThC of accumulation and air on filter membrane 6.
After sampling terminates, take off filter membrane 6 and send into α count measurement instrument and measure, this time interval is T
2, on filter membrane 6
222rn,
220rn daughter is with the quantity of finish time of sampling for initial value starts decay, and daughter nuclide also increases due to the decay of parent nuclide simultaneously, states by following differential equation group:
To formula (2) solve obtain sampling terminate after through T
2time decays, the atomicity of RaA, RaB, RaC, ThB, ThC on filter membrane 6 and the relation of the atomicity of RaA, RaB, RaC, ThB, ThC of sampling finish time.
Utilize α count measurement instrument to start to measure moment to filter membrane 6, the atomicity of RaA, RaB, RaC, ThB, ThC on filter membrane 6 is respectively N
raA1, N
raB1n
raC1, N
thB1, N
thC1, to retrodict RaA, RaB, RaC, ThB, ThC activity concentration obtained in air according to formula (1), (2).
After sampling, filter membrane 6 is sent into α count measurement instrument, start to measure total α and count.
222the alpha-decay of Rn daughter comprises: RaA (
218po) 6.0MeV, RaC` (
214po) 7.69MeV;
220the alpha-decay of Rn daughter comprises: ThC (
212bi) 6.05MeV, ThC` (
212po) 8.78MeV.
After α count measurement instrument starts measurement, on filter membrane 6
222rn,
220rn daughter is still by formula (2) decay, and solve formula (2), the atomicity solving RaA, RaB, RaC, ThB, the ThC of filter membrane 6 upper any time in measuring process is:
Formula (3), (4), (5), (6), (7) are converted to activity form:
The activity of RaA, RaB, RaC, ThB, ThC on filter membrane 6 is respectively A
raA, A
raBa
raC, A
thB, A
thC.
According to
222rn,
220rn Law of radioactive decay is known, total alpha-decay activity A of filter membrane 6 upper any time
α(t) be:
A
α(t)=A
RaA(t)+A
RaC(t)+A
ThC(t)+A
0（13）
A in formula
0for the background counting rate of α count measurement instrument.
With long time interval t
1, t
2, t
3, t
4, t
5, t
6for measuring period, time t
1, t
2, t
3, t
4, t
5, t
6value be respectively 10-120 minute, measuring period is 6.
Its computing method are:
The counting of 6 measuring periods is respectively n (1), n (2), n (3), n (4), n (5), n (6).
By n (1), n (2), n (3), n (4), n (5), n (6) value brings formula (17), (18), (19), (20), (21), (22) into, solves N
raA1, N
raB1n
raC1, N
thB1, N
thC1, A
0the value of value, then retrodict obtain RaA, RaB, RaC, ThB, ThC activity concentration in air according to formula (1), (2).
Claims (2)
1. one kind utilizes in α particle total-count measurement air
222rn,
220the method of Rn daughter, collects on filter membrane by air sampling pump by Radon daughter, then measures the alpha-decay tale on filter membrane, thus calculates radon daughter air concentration; This measuring method is based on following condition:
1) in sampling process
222rn,
220rn daughter concentration and air sampling pump sampling flow rate invariable;
2) filtration efficiency of filter membrane and the self-absorption factor are constant constant, and disobey gasoloid particle diameter and change, and when using miillpore filter, do not have self-absorption;
3) detection efficiency of detector is constant constant, and disobey alpha-particle energy change, depend on filter membrane there is less self-absorption and filter membrane less to detector distance;
?
222rn,
220in Rn daughter sampling process, the radon daughter quantity on filter membrane constantly increases along with sampling, and its quantity also because from parent nuclide decay, increase decays with self and reduces, can be stated by following differential equation group:
(1)
In formula, G is filtration efficiency, and Q is sampling flow rate,
,
,
,
be respectively RaA, RaB, RaC, ThB, ThC activity concentration,
,
,
,
be respectively the half life period of RaA, RaB, RaC, ThB, ThC,
,
,
,
be respectively the atomicity of RaA, RaB, RaC, ThB, the ThC in sampling process, filter membrane accumulated;
Formula (1) is solved and obtains: sampling time T
1at the end of the relation of RaA, RaB, RaC, ThB, ThC activity concentration in the atomicity of RaA, RaB, RaC, ThB, ThC that filter membrane accumulates and air;
After sampling terminates, take off filter membrane feeding α count measurement instrument and measure, this time interval is T
2, on filter membrane
222rn,
220rn daughter is with the quantity of finish time of sampling for initial value starts decay, and daughter nuclide also increases due to the decay of parent nuclide simultaneously, states by following differential equation group:
(2)
To formula (2) solve obtain sampling terminate after through T
2time decays, the atomicity of RaA, RaB, RaC, ThB, ThC on filter membrane and the relation of the atomicity of RaA, RaB, RaC, ThB, ThC of sampling finish time;
Utilize α count measurement instrument to start to measure moment to filter membrane, the atomicity of RaA, RaB, RaC, ThB, ThC on filter membrane is respectively
,
,
,
, to retrodict RaA, RaB, RaC, ThB, ThC activity concentration obtained in air according to formula (1), (2);
After sampling, filter membrane is sent into α count measurement instrument, starts to measure total α and count,
222the alpha-decay of Rn daughter comprises: RaA 6.0MeV, RaC` 7.69MeV;
220the alpha-decay of Rn daughter comprises: ThC 6.05MeV, ThC` 8.78MeV;
After α count measurement instrument starts measurement, on filter membrane
222rn,
220rn daughter is still by formula (2) decay, and solve formula (2), the atomicity solving RaA, RaB, RaC, ThB, the ThC of any time on filter membrane in measuring process is:
（3）
（4）
（5）
（6）
（7）
Formula (3), (4), (5), (6), (7) are converted to activity form:
（8）
（9）
（10）
（11）
（12）
The activity of RaA, RaB, RaC, ThB, ThC on filter membrane is respectively
,
,
,
;
According to
222rn,
220rn Law of radioactive decay is known, total alpha-decay activity of any time on filter membrane
for:
（13）
A in formula
0for the background counting rate of α count measurement instrument;
It is characterized in that: with short time interval t for measuring period, time t is 1-10 minute, and amount of cycles is more than or equal to 6;
Its computing method have two kinds, and two kinds of methods select a use:
A, total α counting according to i-th measuring period
, try to achieve the average counter of the unit interval of i-th measuring period, because measuring period is shorter, these average counters with
in the value approximately equal of this of mid point, have measuring period:
（14）
efor α count measurement instrument is to the detection efficiency of α particle;
Utilize formula (14) right
data carry out nonlinear fitting, can obtain
,
,
,
, A
0value; Then retrodict obtain RaA, RaB, RaC, ThB, ThC activity concentration in air according to formula (1), (2);
B, to ask
integration i-th measuring period:
（15）
Application least square method solves
222rn,
220rn daughter concentration, introduces residual error
:
（16）
In formula
w i be
ithe weight factor of counting section, the different error effect to fitting result of the counting statistics error of each counting section is considered in the introducing of weight factor;
According to principle of least square method, make residual error
get minimum value, can obtain
,
,
,
, A
0value, then retrodict obtain air RaA, RaB, RaC, ThB, ThC activity concentration according to formula (1), (2);
Said method adopts
222rn,
220rn daughter acquisition system forms by with the sampling head of filter membrane, thief rod, flowmeter, connecting pipe and air sampling pump, and sampling head is connected with thief rod, and thief rod is connected with flowmeter, and flowmeter is connected with air sampling pump by connecting pipe.
2. one according to claim 1 utilizes in α particle total-count measurement air
222rn,
220the method of Rn daughter, is characterized in that: in order to long-time interval t
1, t
2, t
3, t
4, t
5, t
6be measuring period for replacing short time interval t measuring period, time t
1, t
2, t
3, t
4, t
5, t
6value be respectively 10-120 minute, measuring period is 6, and its computing method are:
The counting of 6 measuring periods is respectively
,
,
,
,
,
,
（17）
（18）
（19）
（20）
（21）
（22）
Will
,
,
,
,
,
value brings formula (17), (18), (19), (20), (21), (22) into, solves
,
,
,
, A
0the value of value, then retrodict obtain RaA, RaB, RaC, ThB, ThC activity concentration in air according to formula (1), (2).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310069703.5A CN103197336B (en) | 2013-03-06 | 2013-03-06 | Method for rapidly measuring 222Rn and 220Rn daughter concentration in air in terms of alpha general count |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310069703.5A CN103197336B (en) | 2013-03-06 | 2013-03-06 | Method for rapidly measuring 222Rn and 220Rn daughter concentration in air in terms of alpha general count |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103197336A CN103197336A (en) | 2013-07-10 |
| CN103197336B true CN103197336B (en) | 2015-07-08 |
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| CN103439734B (en) * | 2013-09-05 | 2016-09-14 | 衡阳师范学院 | Right222rn,220rn and the method for daughter concentration synchro measure thereof |
| US20160091614A1 (en) * | 2014-09-29 | 2016-03-31 | Battelle Energy Alliance, Llc | Radioactive waste screening systems, and related methods |
| CN104360370B (en) * | 2014-11-11 | 2016-11-30 | 南华大学 | A kind of method of continuous measurement Progeny of thoron concentration |
| CN105954789B (en) * | 2016-04-20 | 2018-05-01 | 南华大学 | A kind of accurate calibration method of measurement of radon daughters instrument alpha energy spectrum overlap of peaks modifying factor |
| CN106019354B (en) * | 2016-06-07 | 2018-10-30 | 南华大学 | Artificial radionuclide concentration monitoring method and device |
| CN107024710A (en) * | 2017-05-12 | 2017-08-08 | 国网吉林省电力有限公司电力科学研究院 | 222Rn radon daughter radioactive levels cumulative effect determines device and method |
| CN112733068B (en) * | 2021-01-08 | 2023-07-25 | 中国辐射防护研究院 | Method for calculating activity of each daughter of radionuclide decay chain |
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| CN101377548A (en) * | 2008-09-29 | 2009-03-04 | 南华大学 | Method and apparatus for rebuilding and measuring 222Rn and 220Rn horizontal alpha energy spectrum in air |
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| US4975574A (en) * | 1990-01-05 | 1990-12-04 | Henry Lucas | Method of and apparatus for measuring the mean concentration of thoron and/or radon in a gas mixture |
| CN101377548A (en) * | 2008-09-29 | 2009-03-04 | 南华大学 | Method and apparatus for rebuilding and measuring 222Rn and 220Rn horizontal alpha energy spectrum in air |
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