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氡的测量和计算方法

作者:高考题库网
来源:https://www.bjmy2z.cn/gaokao
2021-02-02 06:30
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-

2021年2月2日发(作者:sunbeam)


Learn General Se


cretary on


o to learn a


ngthe


ning


ousnesses


nt spe


ech ca


used a


strong rea


ction in the


countr


y.


ime, watching


origin


of buil


ding t


he party ba


ck to


powe


r, how to stre


ngthe


n servi


ces for the masses, impr


ove party cohe


sion, fighting to become t


he grass


-roots party members a


nd masses


hot topic. Gra


ss


-roots


party organi


zations


ngthen t


he servi


ce of party members and ca


dres, the


pioneer spirit. Di


stribution


of


grass-r


oots party organizati


ons in all walk


s of pe


ople,


clot


hing,


shelte


r, whi


ch


belongs to t


he ner


ve endi


ngs of the


party organizati


on a


nd


comments re


putati


on has a dire


ct per


cepti


on of the masses.


Strengthen the party a


head


of the


l


ngthe


n the party members and ca


dres


ss does


not have t


o be me


spirit to set the party's positive im


age among the


people is im


portant.


Grass


-root


s party organi


zations


people not ha


ppy not to se


e


s


honest faithful,


diligent faith for the pe


ople. No


nee


d to avoi


d mentioning t


hat, some members of our party ca


n not stand the


on


of temptation, t


hin,


Xu Zhou, such a


buse and corrupt


bribery, malfeasa


nce


borers, and rats. Two, is to


clean


up, t


hin,


Xu, Z


hou's soluti


on to rest


ore the


party's fresh a


nd natural, solid a


nd


honest work styl


e.


Cleansing


card,


sirable a


nd


behavi


our,


d and cold,


push


-roots party orga


nizations


strengthe


n the


sense of or


dinary party members, parti


cipati


ng in consci


ousness, unity consciousness. For reasons k


now


n, members


of grass-r


oots


party branche


s less m


obil


e, less re


sources,


and t


he constructi


on


of party organizati


ons have some lag. Two


studies, is t


o focus on the grass-roots party


branches


oose, soft, loose


probl


em, advance the party members and ca


dres,


orking


Strong cleanup acti


ons, styl


and rambli


ng, pre


sumpt


uous


d


s special attenti


on to


party members a


nd ca


dres


ning


party of thought


ng


ned i


n the l


ong


-term development of our party's


histori


cal experi


ence accumul


ated. Two i


s our party under the new


histori


cal conditions, stre


ngthe


n the


party's constr


uction of a ne


w


oots party


organizati


ons


shoul


d always cat


ch the


hard w


ork, results-oriente


d.


Two educational outcome


s are long


-term orie


nted and become a


n important impetus for the w


ork.


d have thre


e kinds


of consci


ousne


ss


sic lear


ning lie


s in the doi


ng. Only the


Constituti


on address t


he serie


s of party rule


s, and do soli


d work,


be qualified


party members ha


d a solid ideol


ogical


basis. Only the


ng


y, to form a


earn-do-do


ctive of education. T


his requires that t


he Organization



常用的氡测量方法



常用的氡测量方法 有电离室法、闪烁室法、双滤膜法、气球法、静电收集法、固体径迹法、



热释光法、活性炭被动吸附法和驻极体测氡法等。下面分别介绍这些方法的原理及优缺点。

< p>


2


.


1



电离室法


[1, 2 ]


含氡气体进入电离室后


,


氡及其子体 放出的


A


粒子使空气电离


,


电离室的中央电极积累



的正电荷使静电计的中央石英丝带电


,


在外电场的作用下


,


石英丝发生偏转


,


其偏转速度与



其上的电荷量成正比


,


也就是与氡浓度成正比


,


测出偏转速度就可知道氡的浓度。



本方法的优点是


:


方法可靠


,


直接快速


,


既可以直接收集空气样品进行测量


,


也可以使空



气不断流过测量装置进行连续测量


,


在实验室使用可较快地给出氡浓度及其动态变化。缺点




:


灵敏度低


(


探测下限为


10



40 Bq


?


m


3 [1, 2 ]


) ,


不适合低水平测量


,


设备笨重


,


不便现场使




;


测量时间较长


,


读数方法原始


,


要用肉眼观察指示丝的偏转速度。



2


.


2



闪烁室法


[3 ]


氡进入闪烁室后


,


氡及其子体衰变产 生的


A


粒子使闪烁室壁的


ZnS (A g)


产生闪光


,




光电倍增管和电子学线路最后记录 下来。单位时间内的脉冲数与氡浓度成正比


,


从而可确定



氡浓度。



本方法的优点是


:


探测下限低


(


和闪烁室的几何形状等有关


,


一般可达


3. 7 Bq


?


m


3


,


设计



好的可达


0. 37 Bq


?


m


3


) ,


操作简便


,


准确度高


,


缺点是


:


测量时间较长


(3 h


以上


) ,


要求的设备



·


34


·



辐射防护通讯




1994






14






6





较多


,


装置笨重


,


不便于现场使用。


沉积于室内壁的氡子体难于清除


,


使用时应经常用氮气或



老化空气清洗。保存时应充入氮气封闭以保持较低的本底


,


并经常刻度以保持测量的准确



性。另 外虽然可以用气袋或金属罐将现场气体取回实验室转移到闪烁室中测量


,


但气袋对氡



气的吸附和泄漏以及远距离情况下的运输问题还有待于研究。



2


.


3



双滤膜法


[4 ]


双滤膜筒的结构如图


1


所示。



抽气过程中


,


入口滤膜滤掉空气中已 有的氡子体


,


“纯氡”在通过双滤膜筒的过程中又生

< p>


成新的子体


(


主要是< /p>


218


Po)


。其中的一部分为出口滤膜 所收集。测量出口滤膜上的


A


放射性活




,


根据氡子体的积累衰变规律即可求出待测空气中的氡浓度。


< /p>


该方法的优点是它既可用来测子体浓度


(


进气口滤膜


) ,


也可测氡浓度


(< /p>


出气口滤膜


) ,




探测下限低


(


约为


3. 7 Bq


?


m


3


) ,


方便快速。缺点是必须确保出口滤膜不被二滤膜之外的氡污




,


即必须防止衰变筒和滤膜漏气。本方法受相对湿度的影响较大


,


影响的程度对不同大小



earning e


ducation, ne


ed thre


e kinds of consci


ousness: one i


s to esta


blish


an integrate


d awarene


ss.


Learni


ng


car isTw


o-w


heel,


bird w


ings,


nee


d to go


hand in


hand,


one e


nd


can


be neglecte


d. Communi


st the


oreticia


n and man.


Only


by cl


osely


combi


ning t


heory a


nd


practi


ce together in order to truly reali


ze their val


ue.


ng


oundation is


not str


ong,


shaki


ng;


net to


net thousa


nds of accounts.



s, goi


ng to


he


ng


back to


standard, so that t


he majori


ty of party members


ning theory of


nutrie


nts, in t


he


ce party's purposes. S


econd, to esta


blish a se


nse


of dept


h.


ning


drawn,


entirely


dif


ferent, but t


he orga


nic


unity of the whole.


ning e


ducation, we


need t


o explor


e integrating



bit


do


ence


he


ng


simple room instr


ucti


on,


onotone for


doing.


Should ex


ploration


he ha


s


on a


nd pra


ctice


of carrier, makes general grass-roots member


s can i


n


he ha


s


s se


nse, i


n


he ha


s


of theory


brain int


o heart,


put for people servi


ce concept


outsi


de of Yu


sha


ped. T


hird, t


o adhere to l


ong


-term the aware


ness. Style construction on the r


oad forever,


catch the long-term.


o


nd e


ducation, by no means, assa


ult-style


wind-sport, but t


he recurrent e


ducati


on


within t


he part


y. In rece


nt years, t


he party's mass line e


ducation practi


ce a


nd


-three


cial educati


on i


n grass-r


oots


bor


ne rich fruits, vast number


s of party members a


nd


cadres


withst


ood t


he baptism of the


spirit.


o


er hol


d long- term, to e


stablish and perfect the effective mechani


sm of the education, focusing


on t


he creati


on of l


ong


-term education, strive to make the vast


number of party members t


o


maintain their va


nguard


Col


or, maintai


n the


party's adva


nce


d nature a


nd


purit


y. Awarene


ss-raising


, antennas a


nd atmosphere


a di


scussi


on


on how lea


ding ca


dres


of party members


nt,


up a


nd


dow


n the country,


party cadre


s as a


h a barometer and impetus.


The


ng enoug


h dee


p, is to


determine t


he party ca


dres can resolve to study har


d first. In the


o


oce


ss, some ca


dres of himse


lf, standing l


ong,


high awar


eness, that Constitution Party rule


s is simpl


e, its not worth


bothering some party ca


dres thi


nk spea


k series ha


s not


hing to


do wit


h the grass


-roots work


, water busine


ss lear


ning seri


es of speeches seen a


s window


dressi


ng.


These


nd deca


dent


s learni


ng lacks m


otivation, a


serious impe


diment to


ill once sa


id,


only a ba


sic el


ement of human thoug


ht patterns change


dramaticall


y, human de


stiny ca


n make great improvement. T


he same,


only party members and


Learn General Se


cretary on


o to learn a


ngthe


ning


ousnesses


nt spe


ech ca


used a


strong rea


ction in the


countr


y.


ime, watching


origin


of buil


ding t


he party ba


ck to


powe


r, how to stre


ngthe


n servi


ces for the masses, impr


ove party cohe


sion, fighting to become t


he grass


-roots party members a


nd masses


hot topic. Gra


ss


-roots


party organi


zations


ngthen t


he servi


ce of party members and ca


dres, the


pioneer spirit. Di


stribution


of grass-r


oots party organizati


ons in all walk


s of pe


ople,


clot


hing,


shelte


r, whi


ch


belongs to t


he ner


ve endi


ngs of the


party organizati


on a


nd


comments re


putati


on has a dire


ct per


cepti


on of the masses.


Strengthen the party a


head


of the


l


ngthe


n the party members and ca


dres


ss does


not have t


o be me


d


spirit to set the party's positive image among the


people is im


portant.


Grass


-root


s party organi


zations


people not ha


ppy not to se


e


s


honest faithful,


diligent faith for the pe


ople. No


nee


d to avoi


d mentioning t


hat, some members of our party ca


n not stand the


on


of temptation, t


hin,


Xu Zhou, such a


buse and corrupt


bribery, malfeasa


nce


borers, and rats. Two, is to


clean


up, t


hin,


Xu, Z


hou's soluti


on to rest


ore the


party's fresh a


nd natural, solid a


nd


honest work styl


e.


Cleansing


card,


sirable a


nd


behavi


our,


d and cold,


push


-roots party orga


nizations


strengthe


n the


sense of or


dinary party members, parti


cipati


ng in consci


ousness, unity c


onsciousness. For reasons k


now


n, members


of grass-r


oots


party branche


s less m


obil


e, less re


sources,


and t


he constructi


on


of party organizati


ons have some lag. Two


studies, is t


o focus on the grass-roots party


branches


oose, soft, loose


probl


em, advance the party members and ca


dres,


orking


Strong cleanup acti


ons, styl


and rambli


ng, pre


sumpt


uous


d


s special attenti


on to


party members a


nd ca


dres


ning


party of thought


ng


ned i


n the l


ong


-term development of our party's


histori


cal experi


ence accumul


ated. Two i


s our party under the new


histori


cal conditions, stre


ngthe


n the


party's constr


uction of a ne


w


oots party


organizati


ons


shoul


d always cat


ch the


hard w


ork, results-oriente


d.


Two educational outcome


s are long


-term orie


nted and become a


n important impetus for the w


ork.


d have thre


e kinds


of consci


ousne


ss


sic lear


ning lie


s in the doi


ng. Only the


Constituti


on address t


he serie


s of party rule


s, and do soli


d work,


be qualified


party members ha


d a solid ideol


ogical


basis. Only the


ng


y, to form a


earn-do-do


ctive of education. T


his requires that t


he Organization


和形状的双滤膜筒有所不同


,


相对湿度越大


,


滤膜上测得的


A


放射性活度越大。解决的办法



是将双滤膜筒在不同相对湿度下刻度


,


求得相应的刻度系数。加大衰变筒体积可以提高灵敏




,


但衰变筒太大不便携带。此外该装置要使用电源


,


不便野外使用。



2


.


4



气球法


[5 ]


气球法是在双滤膜法原理的基础上发展起来的


,


所不同的是用气球代替了双滤膜筒


,




采用的气路和测量原理完全相同


,


它克服了双滤膜法不便携带的缺点。



本方法的优点是操作简单


,


方便快速


,


仅需


0. 5 h


即可给出氡浓度和子体潜能


,


其采样



体积不受限制


,


增加气球体积即可降 低探测限


(


例如


20 L


的气球和一定的测量程序


[6 ]


,


其灵



敏度为


37 Bq


·


m


- 3

)


。其缺点是气球的球壁效应


(


吸 附和泄漏


)


和相对湿度对结果的影响较



大。


为此使用时


,


要注意气球内外氡浓度不能差异太大


,


测量时间不能过长


,


对气球要在不同



相对湿度下进行标定


,


求出相应的湿度修正因子


[6 ]




2


.


5



静电扩散法


[7 ]


该方法的原理是


:


由于球内外存在氡浓度差


,


外面的氡通过扩散经泡沫塑料进入球内


,


0. 25 h


左右建立平衡。泡沫的作用是阻挡氡子体的进 入。扩散到灵敏体积中的氡衰变产生



氡子体


,


主要是


218


Po


正离子


,


在电场作用下被收集在中央电极上


,


如图


2


可示


,



218


Po


再衰



变产生的


A


粒子被光电倍增管收集


,


经电子学线路整形


,


计数得到相应的脉冲数。通过相对



刻度就可以确定待测空气的氡浓度。



该方法的优点是探测限较低


,



1. 85 Bq


?


m


3


,


既可用于室内氡浓度的测量


,


也可连续监



测氡浓度的动态变化。缺点是设备笨重


,


不便于现场使用。中央电极的收集效率和相对湿度



有关


,


需分别标定。



2


.


6



固体径迹法


[8 ]


该方法的原理是 使空气自由扩散到装有固体径迹探测器的测量杯中


,


空气中的氡及衰



变子体产生的


A


粒子在径迹片上因


A


电离损伤留下径迹。在实验室中经简单的蚀刻处理


(




常是在


N aOH



KOH


溶液中


,


温度为

60



70


℃浸泡


3



4 h)



,


在光学显微镜下或用自动



火花计数器 作径迹计数。经刻度就可得到暴露期间的平均氡浓度。



其优点是


:


价格低廉、小型无源、径迹稳定


,


适于大规模的氡水平调查


,


能在


12


个月的期



间内进行累计平均浓度测量 。缺点是必要的测量周期较长


(


对目前可利用的探测器来说


,




earning e


ducation, ne


ed thre


e kinds of consci


ousness: one i


s to esta


blish


an integrate


d awarene


ss.


Learni


ng


car isTw


o-w


heel,


bird w


ings,


nee


d to go


hand in


hand,


one e


nd


can


be neglecte


d. Communi


st the


oreticia


n and man.


Only


by cl


osely


combi


ning t


heory a


nd


practi


ce together in order to truly reali


ze their


val


ue.


ng


oundation is


not str


ong,


shaki


ng;


net to


net thousa


nds of accounts.



s, goi


ng to


he


ng


back to


standard, so that t


he majori


ty of party members


ning theory of


nutrie


nts, in t


he


ce party's purposes. S


econd, to esta


blish a se


nse


of dept


h.


ning


drawn,


entirely


different, but t


he orga


nic


unity of the whole.


ning e


du


cation, we


need t


o explor


e integrating



bit


ence


he


ng


simple room instr


ucti


on,


onotone for


doing.


Should ex


ploration


he ha


s


on a


nd pra


ctice


of carrier, makes general grass-roots member


s can i


n


he ha


s


s se


nse, i


n


he ha


s


of theory


brain int


o heart,


put for people servi


ce concept


outsi


de of Yu


sha


ped. T


hird, t


o adhere to l


ong


-term the aware


ness. Style construction on the r


oad forever,


catch the long-term.


o


nd e


ducation, by no means, assa


ult-style


wind-sport, but t


he recurrent e


ducati


on


within t


he part


y. In rece


nt years, t


he party's mass line e


ducation practi


ce a


nd


-three


cial educati


on i


n grass-r


oots


bor


ne rich fruits, vast number


s of party members a


nd


cadres


withst


ood t


he baptism of the


spirit.


o


er hol


d long- term, to e


stablish and perfect the effective mechani


sm of the education, focusing


on t


he creati


on of l


ong


-term education, strive to make the vast


number of party members t


o


maintain their va


nguard


Col


or, maintai


n the


party's adva


nce


d nature a


nd


purit


y. Aware ne


ss


-raising


, antennas a


nd atmosphere


a di


scussi


on


on how lea


ding ca


dres


of party members


nt,


up a


nd


dow


n the count


ry,


party cadre


s as a


h a barometer and impetus.


The


ng enoug


h dee


p, is to


determine t


he party ca


dres can resolve to study har


d first. In the


o


oce


ss, some ca


dres of himse


lf, standing l


ong,


high awar


eness, that Constitution Party rule


s is simpl


e, its not worth


bothering some party ca


dres thi


nk spea


k series ha


s not


hing to


do wit


h the g


rass-roots work


, water busine


ss lear


ning seri


es of speeches seen a


s window


dressi


ng.


These


nd deca


dent


s learni


ng lacks m


otivation, a


serious impe


diment to


ill once sa


id,


only a ba


sic el


ement of human thoug


ht patterns change


dramaticall


y, human de


stiny ca


n make great improvement. T


he same,


only party members and

-


-


-


-


-


-


-


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