CN104122576B - Solid state nuclear track detector is utilized to measure the method and device of 218Po long-time average deposition rate - Google Patents

Abstract

One utilizes solid state nuclear track detector to measure²¹⁸The method and device of Po long-time average deposition rate, during measurement, is fixed on the bottom of measurement apparatus casing and measures metope indoor in environment, and on ground or ceiling top, the measurement time is that the value of T, T is according to measuring requirement for a couple of days to hundreds of skies.After measurement process completes, take off the first solid state nuclear track detector, the second solid state nuclear track detector and the 3rd solid state nuclear track detector immediately, and it is carried out chemical etching, read the nuclear track number on the first solid state nuclear track detector, the second solid state nuclear track detector and the 3rd solid state nuclear track detector respectively, and by being calculated²¹⁸The long-time average deposition rate of Po.

Description

Utilize the method that solid state nuclear track detector measures 218Po long-time average deposition rate And device

Technical field

The present invention relates to a kind of nuclear radiation detection technology, particularly one utilizes solid state nuclear track detector to measure²¹⁸Po length The method and device of time average deposition rate.

Background technology

In air ambient, radon is the main source of natural radiation suffered by human body, inherently sees, human body is exhaled by the daughter of radon Desorption system radiation is the major reason causing lung cancer.Radon in air has²²²Rn and²²⁰Rn, due to²²²Rn concentration is typically remote high In²²⁰Rn concentration, environment activity is mainly monitored object and is exactly²²²The daughter of Rn, wherein²¹⁸Po is²²²In Rn decay chain first Level, has particularly important meaning.Traditional active measuring method is usually and uses filter membrane to sample the radon daughter in air, Then being analyzed by tale or Method of Energy Spectrum Analysis obtains the concentration of Radon daughter, the method is accurately quick, but only The data of sampling time section can be reflected, it is impossible to obtain long average data.Affect in room air²¹⁸Po concentration because of Element mainly has²²²The concentration of Rn, ventilation rate and²¹⁸Po deposition these three parameter is so-called²¹⁸In Po deposition is exactly the unit interval In unit are body of wall, ground or roof deposition²¹⁸The activity of Po.

Summary of the invention

It is an object of the invention to overcome the above-mentioned deficiency of prior art to provide one to utilize solid state nuclear track detector to survey Amount²¹⁸The method and device of Po long-time average deposition rate.

The technical scheme is that one utilizes solid state nuclear track detector to measure²¹⁸Po long-time average deposition rate Method, its concrete measuring method is as follows:

A, measurement process:

The bottom of measurement apparatus casing is fixed on and measures metope indoor in environment or ground or ceiling On top, being provided with three solid state nuclear track detectors in the casing of measurement apparatus, three solid state nuclear track detectors are respectively first Solid state nuclear track detector, the second solid state nuclear track detector and the 3rd solid state nuclear track detector, the first solid state nuclear track is visited The surface area surveying device is S₁, the surface area of the second solid state nuclear track detector is S₂, the surface area of the 3rd solid state nuclear track detector For S₃, and meet: S₁≤S₂≤S₃。

It is D that the surface of the second solid state nuclear track detector is coated with thickness₁Primary diaphragm, the surface configuration of primary diaphragm with The surface configuration of the second solid state nuclear track detector is the same.It is D that the surface of the 3rd solid state nuclear track detector is coated with thickness₂The Two diaphragms, the surface configuration of secondary diaphragm is as the surface configuration of the 3rd solid state nuclear track detector.The thickness of primary diaphragm D₁Thickness D less than secondary diaphragm₂, primary diaphragm can stop²²²Rn daughter²¹⁸The particle of the 6MeV that Po decay produces gets to second On solid state nuclear track detector, secondary diaphragm can stop²²²Rn daughter²¹⁸Po and²¹⁴6MeV's and 7.69MeV that Po decay produces Particle is got on the 3rd solid state nuclear track detector.

The surface of the first solid state nuclear track detector is not covered with diaphragm,²²⁰Rn daughter²¹²The 8.78MeV that Po decay produces Particle can get on first, second, third solid state nuclear track detector.

The measurement time is that the value of T, T is according to measuring requirement for a couple of days to hundreds of skies.

B, calculating process:

Random time t during measuring, deposited per area unit on solid state nuclear track detector²²²Rn daughter activity Be changed to:

$\frac{{\mathrm{dA}}_{Po218}\left(t\right)}{dt}=D_{Po218}-{\mathrm{\λ}}_{Po218}{A}_{Po218}\left(t\right)---\left(1\right)$

$\frac{{\mathrm{dA}}_{Pb214}\left(t\right)}{dt}=D_{Pb214}+{\mathrm{\λ}}_{Pb214}{A}_{Po218}\left(t\right)-{\mathrm{\λ}}_{Pb214}{A}_{Pb214}\left(t\right)---\left(2\right)$

$\frac{{\mathrm{dA}}_{Bi214}\left(t\right)}{dt}=D_{Bi214}+{\mathrm{\λ}}_{Bi214}{A}_{Pb214}\left(t\right)-{\mathrm{\λ}}_{Bi214}{A}_{Bi214}\left(t\right)---\left(3\right)$

A_Po214(t)=A_Bi214(t) (4)

In formula: A_Po218(t)、A_Pb214(t)、A_Bi214(t)、A_Po214T () is respectively²¹⁸Po、 ²¹⁴Pb、²¹⁴Bi、²¹⁴Po is at solid Activity on nuclear track detector；D_Po218、D_Pb214、D_Bi214It is²¹⁸Po、²¹⁴Pb、²¹⁴The deposition of Bi；λ_Po218、λ_Pb214、λ_Bi214 It is²¹⁸Po、²¹⁴Pb、 ²¹⁴The decay coefficient of Bi.

Owing in measurement apparatus, the high frame of casing blocks what chamber internal surface directly separated out²²⁰Rn and short life son Body arrives the surface of solid core detector, only considers its long-life daughter.Deposited per area unit on solid state nuclear track detector 's²²⁰Rn long-life daughter²¹²Pb、 ²¹²Bi、²¹²The change of Po activity is respectively as follows: A_Pb212(t)、A_Bi212(t)、A_Po212(t)。

After measurement process completes, take off the first solid state nuclear track detector, the second solid state nuclear track detector and immediately Three solid state nuclear track detectors, and it is carried out chemical etching, read the first solid state nuclear track detector, the second solid core respectively Nuclear track number on track detector and the 3rd solid state nuclear track detector.

Particle track number N on first solid state nuclear track detector₁For:

$\begin{array}{c}{N}_1={\mathrm{\η}}_{1Po218}{S}_1{\∫}_0^T{A}_{Po218}\left(t\right)dt+{\mathrm{\η}}_{1Po214}{S}_1{\∫}_0^T{A}_{Po214}\left(t\right)dt\\ +0.36{\mathrm{\η}}_{1Bi212}{S}_1{\∫}_0^T{A}_{Bi212}\left(t\right)dt+{\mathrm{\η}}_{1Po212}{S}_1{\∫}_0^T{A}_{Po212}\left(t\right)dt\end{array}---\left(5\right)$

η in formula_1Po218、η_1Po214、η_1Bi212、η_1Po212Represent the first solid state nuclear track detector pair respectively²¹⁸Po、²¹⁴Po、²¹²Bi、²¹²The detection efficient of the decay of Po, wherein due to²¹⁸Po、 ²¹²The particle energy that Bi decay produces is close, and it detects effect Rate is the most identical.

Particle track number N on second solid state nuclear track detector₂For:

$N_2={\mathrm{\η}}_{2Po214}{S}_2{\∫}_0^T{A}_{Po214}\left(t\right)dt+{\mathrm{\η}}_{2Po212}{S}_2{\∫}_0^T{A}_{Po212}\left(t\right)dt---\left(6\right)$

η in formula_2Po214、η_2Po212Represent the second solid state nuclear track detector pair respectively²¹⁴Po、 ²¹²The detection of the decay of Po Efficiency.

Particle track number N on 3rd solid state nuclear track detector₃For:

$N_3={\mathrm{\η}}_{3Po212}{S}_3{\∫}_0^T{A}_{Po212}\left(t\right)dt---\left(7\right)$

η in formula_3Po212Represent the 3rd solid state nuclear track detector pair²¹²The detection efficient of the decay of Po.

According to²²⁰Rn decay chain is the most available:

A_Po212(t)=0.64A_Bi212(t) (8)

Be can get by formula (5), (6), (7), (8):

$\begin{array}{c}{N}_1={\mathrm{\η}}_{1Po218}{S}_1{\∫}_0^T{A}_{po218}\left(t\right)dt+\frac{{\mathrm{\η}}_{1Po214}{S}_1}{{\mathrm{\η}}_{2Po214}{S}_2}(N_2-\frac{{\mathrm{\η}}_{2Po212}{S}_2}{{\mathrm{\η}}_{3Po212}{S}_3}{N}_3)\\ +\frac{0.36{\mathrm{\η}}_{1Bi212}{S}_1}{0.64{\mathrm{\η}}_{3Po212}{S}_3}{N}_3+\frac{{\mathrm{\η}}_{1Po212}{S}_1}{{\mathrm{\η}}_{3Po212}{S}_3}{N}_3\end{array}---\left(9\right)$

Just can be solved by formula (9)D just can be back-calculated to obtain again by formula (1)_Po218I.e.²¹⁸Po's is long-time flat All depositions.

The measurement apparatus that said method uses includes casing, and casing is a lower end closed, the container of upper end open, casing Cavity heights h be 2～8cm.Be provided with the first solid state nuclear track detector on the base plate of casing, the second solid state nuclear track is visited Surveying device and the 3rd solid state nuclear track detector, the first solid state nuclear track detector, the second solid state nuclear track detector and the 3rd are solid Body nuclear track detector is attached on the base plate of casing respectively by the way of bonding.The surface area of the first solid state nuclear track detector For S₁, the surface area of the second solid state nuclear track detector is S₂, the surface area of the 3rd solid state nuclear track detector is S₃, and meet: S₁≤S₂≤S₃.It is D that the surface of the second solid state nuclear track detector is coated with thickness₁Primary diaphragm, the surface configuration of primary diaphragm As the surface configuration of the second solid state nuclear track detector.It is D that the surface of the 3rd solid state nuclear track detector is coated with thickness₂ Secondary diaphragm, the surface configuration of secondary diaphragm is as the surface configuration of the 3rd solid state nuclear track detector.The thickness of primary diaphragm Degree D₁Thickness D less than secondary diaphragm₂。

The present invention compared with prior art has a characteristic that

Measurement apparatus, measurement process and computational methods that the present invention provides are simple, it is possible to measure²¹⁸Po is the most heavy Long-pending rate.

Below in conjunction with the drawings and specific embodiments, the detailed construction of the present invention is further described.

Accompanying drawing explanation

Accompanying drawing 1 is the structural representation of the present invention；

Accompanying drawing 2 is the A-A sectional view in accompanying drawing 1.

Detailed description of the invention

One utilizes solid state nuclear track detector to measure²¹⁸The method of Po long-time average deposition rate, its concrete measuring method As follows:

A, measurement process:

The bottom of measurement apparatus casing 1 is fixed on and measures metope indoor in environment or ground or ceiling On top, being provided with three solid state nuclear track detectors in the casing 1 of measurement apparatus, three solid state nuclear track detectors are respectively first Solid state nuclear track detector the 2, second solid state nuclear track detector 3 and the 3rd solid state nuclear track detector 5, the first solid state nuclear track The surface area of detector 2 is S₁, the surface area of the second solid state nuclear track detector 3 is S₂, the 3rd solid state nuclear track detector 5 Surface area is S₃, and meet: S₁≤S₂≤S₃。

It is D that the surface of the second solid state nuclear track detector 3 is coated with thickness₁Primary diaphragm 4, the surface shape of primary diaphragm 4 The surface configuration of shape and the second solid state nuclear track detector 3 is the same.The surface of the 3rd solid state nuclear track detector 5 is coated with thickness For D₂Secondary diaphragm 6, the surface configuration of secondary diaphragm 6 is as the surface configuration of the 3rd solid state nuclear track detector 5.First film The thickness D of sheet 4₁Thickness D less than secondary diaphragm 6₂, primary diaphragm 4 can stop²²²Rn daughter²¹⁸The 6MeV's that Po decay produces Particle is got on the second solid state nuclear track detector 3, and secondary diaphragm 6 can stop²²²Rn daughter²¹⁸Po and²¹⁴Po decay produces The particle of 6MeV and 7.69MeV is got on the 3rd solid state nuclear track detector 5.

The surface of the first solid state nuclear track detector 2 is not covered with diaphragm,²²⁰Rn daughter²¹²Po decay produces The particle of 8.78MeV can get to first solid state nuclear track detector the 2, second solid state nuclear track detector the 3, the 3rd solid core footpath On mark detector 5.

The measurement time is that the value of T, T is according to measuring requirement for a couple of days to hundreds of skies.

B, calculating process:

Random time t during measuring, deposited per area unit on solid state nuclear track detector²²²Rn daughter activity Be changed to:

$\frac{{\mathrm{dA}}_{Po218}\left(t\right)}{dt}=D_{Po218}-{\mathrm{\λ}}_{Po218}{A}_{Po218}\left(t\right)---\left(1\right)$

$\frac{{\mathrm{dA}}_{Pb214}\left(t\right)}{dt}=D_{Pb214}+{\mathrm{\λ}}_{Pb214}{A}_{Po218}\left(t\right)-{\mathrm{\λ}}_{Pb214}{A}_{Pb214}\left(t\right)---\left(2\right)$

$\frac{{\mathrm{dA}}_{Bi214}\left(t\right)}{dt}=D_{Bi214}+{\mathrm{\λ}}_{Bi214}{A}_{Pb218}\left(t\right)-{\mathrm{\λ}}_{Bi214}{A}_{Bi214}\left(t\right)---\left(3\right)$

A_Po214(t)=A_Bi214(t) (4)

In formula: A_Po218(t)、A_Pb214(t)、A_Bi214(t)、A_Po214T () is respectively²¹⁸Po、 ²¹⁴Pb、²¹⁴Bi、²¹⁴Po is at solid Activity on nuclear track detector；D_Po218、D_Pb214、D_Bi214It is²¹⁸Po、²¹⁴Pb、²¹⁴The deposition of Bi；λ_Po218、λ_Pb214、λ_Bi214 It is²¹⁸Po、²¹⁴Pb、 ²¹⁴The decay coefficient of Bi.

Owing in measurement apparatus, the high frame of casing 1 blocks what chamber internal surface directly separated out²²⁰Rn and short life son Body arrives the surface of solid core detector, only considers its long-life daughter.Deposited per area unit on solid state nuclear track detector 's²²⁰Rn long-life daughter²¹²Pb、²¹²Bi、²¹²The change of Po activity is respectively as follows: A_Pb212(t)、A_Bi212(t)、A_Po212(t)。

After measurement process completes, take off first solid state nuclear track detector the 2, second solid state nuclear track detector 3 and immediately 3rd solid state nuclear track detector 5, and it is carried out chemical etching, read the first solid state nuclear track detector 2, second respectively solid Nuclear track number on body nuclear track detector 3 and the 3rd solid state nuclear track detector 5.

Particle track number N on first solid state nuclear track detector 2₁For:

$\begin{array}{c}{N}_1={\mathrm{\η}}_{1Po218}{S}_1{\∫}_0^T{A}_{Po218}\left(t\right)dt+{\mathrm{\η}}_{1Po214}{S}_1{\∫}_0^T{A}_{Po218}\left(t\right)dt\\ +0.36{\mathrm{\η}}_{1Bi212}{S}_1{\∫}_0^T{A}_{Bi212}\left(t\right)dt+{\mathrm{\η}}_{1Po212}{S}_1{\∫}_0^T{A}_{Po212}\left(t\right)dt\end{array}---\left(5\right)$

η in formula_1Po218、η_1Po214、η_1Bi212、η_1Po212Represent that the first solid state nuclear track detector 2 is right respectively²¹⁸Po、²¹⁴Po 、²¹²Bi、²¹²The detection efficient of the decay of Po, wherein due to²¹⁸Po、²¹²The particle energy that Bi decay produces is close, its detection Efficiency is the most identical.

Particle track number N on second solid state nuclear track detector 3₂For:

$N_2={\mathrm{\η}}_{2Po214}{S}_2{\∫}_0^T{A}_{Po214}\left(t\right)dt+{\mathrm{\η}}_{2Po212}{S}_2{\∫}_0^T{A}_{Po212}\left(t\right)dt---\left(6\right)$

η in formula_2Po214、η_2Po212Represent that the second solid state nuclear track detector 3 is right respectively²¹⁴Po、²¹²The detection of the decay of Po Efficiency.

Particle track number N on 3rd solid state nuclear track detector 5₃For:

$N_3={\mathrm{\η}}_{3Po212}{S}_3{\∫}_0^T{A}_{Po212}\left(t\right)dt---\left(7\right)$

η in formula_3Po212Represent that the 3rd solid state nuclear track detector 5 is right²¹²The detection efficient of the decay of Po.

According to²²⁰Rn decay chain is the most available:

A_Po212(t)=0.64A_Bi212(t) (8)

Be can get by formula (5), (6), (7), (8):

$\begin{array}{c}{N}_1={\mathrm{\η}}_{1Po218}{S}_1{\∫}_0^T{A}_{po218}\left(t\right)dt+\frac{{\mathrm{\η}}_{1Po214}{S}_1}{{\mathrm{\η}}_{2Po214}{S}_2}(N_2-\frac{{\mathrm{\η}}_{2Po212}{S}_2}{{\mathrm{\η}}_{3Po212}{S}_3}{N}_3)\\ +\frac{0.36{\mathrm{\η}}_{1Bi212}{S}_1}{0.64{\mathrm{\η}}_{3Po212}{S}_3}{N}_3+\frac{{\mathrm{\η}}_{1Po212}{S}_1}{{\mathrm{\η}}_{3Po212}{S}_3}{N}_3\end{array}---\left(9\right)$

Just can be solved by formula (9)D just can be back-calculated to obtain again by formula (1)_Po218I.e.²¹⁸Po's is long-time flat All depositions.

The measurement apparatus that said method uses includes that casing 1, casing 1 are a lower end closed, the container of upper end open, case The cavity heights h of body 1 is 2～8cm.The base plate of casing 1 is provided with first solid state nuclear track detector the 2, second solid core footpath Mark detector 3 and the 3rd solid state nuclear track detector 5, first solid state nuclear track detector the 2, second solid state nuclear track detector 3 It is attached on the base plate of casing 1 by the way of bonding respectively with the 3rd solid state nuclear track detector 5.First solid state nuclear track detection The surface area of device 2 is S₁, the surface area of the second solid state nuclear track detector 3 is S₂, the surface of the 3rd solid state nuclear track detector 5 Amass as S₃, and meet: S₁≤S₂≤S₃.It is D that the surface of the second solid state nuclear track detector 3 is coated with thickness₁Primary diaphragm 4, the The surface configuration of one diaphragm 4 is as the surface configuration of the second solid state nuclear track detector 3.3rd solid state nuclear track detector 5 To be coated with thickness be D on surface₂The table of secondary diaphragm 6, the surface configuration of secondary diaphragm 6 and the 3rd solid state nuclear track detector 5 Face shape is the same.The thickness D of primary diaphragm 4₁Thickness D less than secondary diaphragm 6₂。

Claims (3)

1. one kind utilizes solid state nuclear track detector to measure²¹⁸The method of Po long-time average deposition rate, is characterized in that: it is concrete Measuring method is as follows:

A, measurement process:

The bottom of measurement apparatus casing is fixed on and measures on metope indoor in environment or ground or ceiling top, Being provided with three solid state nuclear track detectors in the casing of measurement apparatus, three solid state nuclear track detectors are respectively the first solid core Track detector, the second solid state nuclear track detector and the 3rd solid state nuclear track detector, the first solid state nuclear track detector Surface area is S₁, the surface area of the second solid state nuclear track detector is S₂, the surface area of the 3rd solid state nuclear track detector is S₃, And meet: S₁≤S₂≤S₃；

It is D that the surface of the second solid state nuclear track detector is coated with thickness₁Primary diaphragm, the surface configuration of primary diaphragm and second The surface configuration of solid state nuclear track detector is the same, and it is D that the surface of the 3rd solid state nuclear track detector is coated with thickness₂Second film Sheet, the surface configuration of secondary diaphragm as the surface configuration of the 3rd solid state nuclear track detector, the thickness D of primary diaphragm₁Little Thickness D in secondary diaphragm₂, primary diaphragm can stop²²²Rn daughter²¹⁸It is solid that the particle of the 6MeV that Po decay produces gets to second On body nuclear track detector, secondary diaphragm can stop²²²Rn daughter²¹⁸Po and²¹⁴The grain of 6MeV and 7.69MeV that Po decay produces Son is got on the 3rd solid state nuclear track detector；

The surface of the first solid state nuclear track detector is not covered with diaphragm,²²⁰Rn daughter²¹²The grain of the 8.78MeV that Po decay produces Son can be got on first, second, third solid state nuclear track detector；

The measurement time is that the value of T, T is according to measuring requirement for a couple of days to hundreds of skies；

B, calculating process:

Random time t during measuring, deposited per area unit on solid state nuclear track detector²²²The change of Rn daughter activity Turn to:

$\frac{{\mathrm{dA}}_{Po218}\left(t\right)}{dt}=D_{Po218}-{\mathrm{\λ}}_{Po218}{A}_{Po218}\left(t\right)---\left(1\right)$

$\frac{{\mathrm{dA}}_{Pb214}\left(t\right)}{dt}=D_{Pb214}+{\mathrm{\λ}}_{Pb214}{A}_{Po218}\left(t\right)-{\mathrm{\λ}}_{Pb214}{A}_{Pb214}\left(t\right)---\left(2\right)$

$\frac{{\mathrm{dA}}_{Bi214}\left(t\right)}{dt}=D_{Bi214}+{\mathrm{\λ}}_{Bi214}{A}_{Pb214}\left(t\right)-{\mathrm{\λ}}_{Bi214}{A}_{Bi214}\left(t\right)---\left(3\right)$

A_Po214(t)=A_Bi214(t) (4)

In formula: A_Po218(t)、A_Pb214(t)、A_Bi214(t)、A_Po214T () is respectively²¹⁸Po、²¹⁴Pb、²¹⁴Bi、²¹⁴Po is in solid core footpath Activity on mark detector；D_Po218、D_Pb214、D_Bi214It is²¹⁸Po、²¹⁴Pb、²¹⁴The deposition of Bi；λ_Po218、λ_Pb214、λ_Bi214It is²¹⁸Po、²¹⁴Pb、²¹⁴The decay coefficient of Bi；

Owing in measurement apparatus, the high frame of casing blocks what chamber internal surface directly separated out²²⁰Rn and short life daughter arrive Reach the surface of solid core detector, only consider its long-life daughter, deposited per area unit on solid state nuclear track detector²²⁰Rn long-life daughter²¹²Pb、²¹²Bi、²¹²The change of Po activity is respectively as follows: A_Pb212(t)、A_Bi212(t)、A_Po212(t)；

After measurement process completes, take off the first solid state nuclear track detector, the second solid state nuclear track detector and the 3rd immediately solid Body nuclear track detector, and it is carried out chemical etching, read the first solid state nuclear track detector, the second solid state nuclear track respectively Nuclear track number on detector and the 3rd solid state nuclear track detector；

Particle track number N on first solid state nuclear track detector₁For:

$\begin{array}{c}{N}_1={\mathrm{\η}}_{1Po218}{S}_1{\∫}_0^T{A}_{Po218}\left(t\right)dt+{\mathrm{\η}}_{1Po214}{S}_1{\∫}_0^T{A}_{Po214}\left(t\right)dt\\ +0.36{\mathrm{\η}}_{1Bi212}{S}_1{\∫}_0^T{A}_{Bi212}\left(t\right)dt+{\mathrm{\η}}_{1Po212}{S}_1{\∫}_0^T{A}_{Po212}\left(t\right)dt\end{array}---\left(5\right)$

η in formula_1Po218、η_1Po214、η_1Bi212、η_1Po212Represent the first solid state nuclear track detector pair respectively²¹⁸Po、²¹⁴Po、²¹²Bi 、²¹²The detection efficient of the decay of Po, wherein due to²¹⁸Po、²¹²The particle energy that Bi decay produces is close, and its detection efficient is also Identical；

Particle track number N on second solid state nuclear track detector₂For:

$N_2={\mathrm{\η}}_{2Po214}{S}_2{\∫}_0^T{A}_{Po214}\left(t\right)dt+{\mathrm{\η}}_{2Po212}{S}_2{\∫}_0^T{A}_{Po212}\left(t\right)dt---\left(6\right)$

η in formula_2Po214、η_2Po212Represent the second solid state nuclear track detector pair respectively²¹⁴Po、²¹²The detection efficient of the decay of Po；

Particle track number N on 3rd solid state nuclear track detector₃For:

$N_3={\mathrm{\η}}_{3Po212}{S}_3{\∫}_0^T{A}_{Po212}\left(t\right)dt---\left(7\right)$

η in formula_3Po212Represent the 3rd solid state nuclear track detector pair²¹²The detection efficient of the decay of Po；

According to²²⁰Rn decay chain is the most available:

A_Po212(t)=0.64A_Bi212(t)(8)

Be can get by formula (5), (6), (7), (8):

$\begin{array}{c}{N}_1={\mathrm{\η}}_{1Po218}{S}_1{\∫}_0^T{A}_{Po218}\left(t\right)dt+\frac{{\mathrm{\η}}_{1Po214}{S}_1}{{\mathrm{\η}}_{2Po214}{S}_1}\left(N_2-\frac{{\mathrm{\η}}_{2Po212}{S}_2}{{\mathrm{\η}}_{3Po212}{S}_3}{N}_3\right)\\ +\frac{0.36{\mathrm{\η}}_{1Bi212}{S}_1}{0.64{\mathrm{\η}}_{3Po212}{S}_3}{N}_3+\frac{{\mathrm{\η}}_{1Po212}{S}_1}{{\mathrm{\η}}_{3Po212}{S}_3}{N}_3\end{array}---\left(9\right)$

Just can be solved by formula (9)D just can be back-calculated to obtain again by formula (1)_Po218I.e.²¹⁸The long-time average deposition of Po Rate.

One the most according to claim 1 utilizes solid state nuclear track detector to measure²¹⁸The side of Po long-time average deposition rate Method, is characterized in that: described measurement apparatus includes casing, and casing is a lower end closed, the container of upper end open, at casing Base plate is provided with the first solid state nuclear track detector, the second solid state nuclear track detector and the 3rd solid state nuclear track detector, the One solid state nuclear track detector, the second solid state nuclear track detector and the 3rd solid state nuclear track detector are respectively by the side of bonding Formula is attached on the base plate of casing；It is D that the surface of the second solid state nuclear track detector is coated with thickness₁Primary diaphragm, the 3rd solid It is D that the surface of nuclear track detector is coated with thickness₂Secondary diaphragm.

One the most according to claim 2 utilizes solid state nuclear track detector to measure²¹⁸The side of Po long-time average deposition rate Method, is characterized in that: the cavity heights h of casing is 2～8cm.