长距离α污染测量仪的研制
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摘要
在核设施退役和核辐射检测领域,需要检测管道内表面α污染,从而了解管道内的α污染情况,以做出相应处理措施,这是人们为自身健康、安全和环境免遭放射性核素污染而采取的一种监测措施。由于α射线射程极短、穿透力很弱,对于受α辐射污染的物件,尤其是探测器不易靠近和几何形状不规则的污染表面,如小直径长管道的内表面,使用传统的监测方法,如手持探头法和擦拭法,来进行活度监测将会非常困难甚至失效。对于异形物体表面的核辐射α污染监测,长距离α污染监测(Long range alpha detection,LRAD)技术提供了一种新方法。LRAD技术依据的基础是α电离作用产生的离子在空气中复合需要数秒的时间,如果在此时间内气流能有效地将污染处的离子传输到较远处的接收极板上,就能够对数米长管道内表面α污染的活度进行测量。基于LRAD技术的原理,我们研制了新型的长距离α污染测量仪。该测量仪是基于单片机设计开发的,硬件系统主要由电风扇驱动单元、电离室、电流电压转换器、以单片机为核心的信号采集处理系统、LCD显示、电源(锂电池和DC-DC)和充电器等组成。
经过近一年的研制工作,论文主要取得了以下研究成果:
1、设计了电流电离室,该电离室能够测量fA级的弱电流,探测效率高,性能稳定;
2、以单片机为控制核心,完成了数据的采集、存储、分析等过程;
3、系统的人机交互界面使用了点阵式液晶显示器和小键盘,操作界面为汉字显示,界面友好;
4、研制了适合本系统的电源电路和锂电池充电电路。设计了仪器面板和机壳,对仪器进行整机装配;
5、选用标准源作为基准,对仪器的重复性和稳定性进行了相应的测试,测试结果表明,该仪器性能良好。
使用证明,该测量仪性能稳定,可以检测到传统α表面污染仪探头不能探测到的管道内表面污染情况,在监测小直径长管道内表面α活度时,既不需要对被测管道进行有损处理,又能实时、高效、安全地对其进行活度监测。
In the nuclear facility retirement and the nuclear radiation examination domain, needs to examine the pipe internal surface alpha pollution,to understood the alpha pollution in the pipe,makes the corresponding processing measures,this is one kind of monitor measure adopted by people for their own health,safety and the environment avoids radionuclide pollution.Because alpha particle have very short range and extremely weak penetration in the air,it is difficult for the detectors to get close to the surface pollution of irregular geometric shapes,such as small diameter long pipe.When its inner surface is monitored,it is very difficult to achieve results through hand-held probe methods or to use polished methods.Regarding the heteromorphous object surface's nuclear radiation pollution monitor,the long range alpha detection(LRAD)technology has provided one new method.The LRAD technology basis's foundation is the ion which the alpha ionization produces compound requires several seconds time in the air,if the air current can effectively transport the pollution place ion to the distant place receive pole plate in this time,can the long pipe internal surface pollution activity carry on the survey.Based on the LRAD technology's principle,we have developed the new long rang alpha contamination instrument.The measuring instrument is based on the SCM development,the hardware system is mainly composed of fan driving unit,ionization chamber,current -voltage converter,the signal acquisition and processing system taken the SCM as the core,LCD display,power(Li-ion battery and DC-DC)and chargers,and so on.
After nearly a year of development work,the results are:
1.Has designed the current ionization chamber,which can survey the fA level weak-current,the detection efficiency is high,stable property.
2.Take the SCM as the control core,has completed the data collection,memory, and analysis process.
3.System's man-machine interface has used the lattice type liquid-crystal display and the small keyboard,the interface demonstrated in the Chinese character that the interface is friendly.
4.Has developed power circuit and the lithium battery charging circuit for this system.Has designed the board and the cabinet,and assembled the instrument.
5.Selected the standard radioactive source,carried on the instrument's duplication and stability test,the test result had indicated that this instrument performance was good.
Use show that the measuring instrument stable performance,can detect the pipe internal surface contamination which the traditional alpha surface contamination instrument detector can't detect.When monitoring the small diameter long pipe internal surface activity,does not need to conduct prejudicial to deal with the measured channels,but also can real-time,highly effective,carry on the activity monitor safely to it.
经过近一年的研制工作,论文主要取得了以下研究成果:
1、设计了电流电离室,该电离室能够测量fA级的弱电流,探测效率高,性能稳定;
2、以单片机为控制核心,完成了数据的采集、存储、分析等过程;
3、系统的人机交互界面使用了点阵式液晶显示器和小键盘,操作界面为汉字显示,界面友好;
4、研制了适合本系统的电源电路和锂电池充电电路。设计了仪器面板和机壳,对仪器进行整机装配;
5、选用标准源作为基准,对仪器的重复性和稳定性进行了相应的测试,测试结果表明,该仪器性能良好。
使用证明,该测量仪性能稳定,可以检测到传统α表面污染仪探头不能探测到的管道内表面污染情况,在监测小直径长管道内表面α活度时,既不需要对被测管道进行有损处理,又能实时、高效、安全地对其进行活度监测。
In the nuclear facility retirement and the nuclear radiation examination domain, needs to examine the pipe internal surface alpha pollution,to understood the alpha pollution in the pipe,makes the corresponding processing measures,this is one kind of monitor measure adopted by people for their own health,safety and the environment avoids radionuclide pollution.Because alpha particle have very short range and extremely weak penetration in the air,it is difficult for the detectors to get close to the surface pollution of irregular geometric shapes,such as small diameter long pipe.When its inner surface is monitored,it is very difficult to achieve results through hand-held probe methods or to use polished methods.Regarding the heteromorphous object surface's nuclear radiation pollution monitor,the long range alpha detection(LRAD)technology has provided one new method.The LRAD technology basis's foundation is the ion which the alpha ionization produces compound requires several seconds time in the air,if the air current can effectively transport the pollution place ion to the distant place receive pole plate in this time,can the long pipe internal surface pollution activity carry on the survey.Based on the LRAD technology's principle,we have developed the new long rang alpha contamination instrument.The measuring instrument is based on the SCM development,the hardware system is mainly composed of fan driving unit,ionization chamber,current -voltage converter,the signal acquisition and processing system taken the SCM as the core,LCD display,power(Li-ion battery and DC-DC)and chargers,and so on.
After nearly a year of development work,the results are:
1.Has designed the current ionization chamber,which can survey the fA level weak-current,the detection efficiency is high,stable property.
2.Take the SCM as the control core,has completed the data collection,memory, and analysis process.
3.System's man-machine interface has used the lattice type liquid-crystal display and the small keyboard,the interface demonstrated in the Chinese character that the interface is friendly.
4.Has developed power circuit and the lithium battery charging circuit for this system.Has designed the board and the cabinet,and assembled the instrument.
5.Selected the standard radioactive source,carried on the instrument's duplication and stability test,the test result had indicated that this instrument performance was good.
Use show that the measuring instrument stable performance,can detect the pipe internal surface contamination which the traditional alpha surface contamination instrument detector can't detect.When monitoring the small diameter long pipe internal surface activity,does not need to conduct prejudicial to deal with the measured channels,but also can real-time,highly effective,carry on the activity monitor safely to it.
引文
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[5]曾旖,庹先国,李向阳,奚大顺.镍镉电池智能充电器的研制[J].电子技术应用,2006(6).
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[10]J.D.Johnson,K.S.Allander,J.A.Bounds,S.E.Garner,J.P.Johnson,D.W.MacArthur and L.Sprouse.Recent Advances of the Electrostatic Long-Range Alpha Detector[J].National Technical Information Service,1994.
[11]http://www.osti.gov/bridge/servlets/purl/10139176-ySpu56/native/10139176.pdf.
[12]高嵩.基于嵌入式PC/104模块的核谱仪系统的研究[D].四川:成都理工大学,2004.
[2]贾文懿.核地球物理仪器[M].北京:原子能出版社,1998.8.
[3]潘福彬.α能谱数据采集系统软硬件设计[D].四川:成都理工大学,2005.
[4]孙海,孟祥,邓学伟.AD7715模数转换器在小信号测量中的应用[J].测控技术,2003,29(3).
[5]曾旖,庹先国,李向阳,奚大顺.镍镉电池智能充电器的研制[J].电子技术应用,2006(6).
[6]梁晋文等.误差理论与数据处理[M].北京:中国计量出版社,1989,8.
[7]廖哲等.新型α表面污染报警测量仪[J].全国第四届核仪器及其应用学术会议论文集,2003,9.
[8]张国华.空气脉冲电离室α测氡仪的研制[D].四川:成都理工大学,2006.
[9]奚大顺,何为民.放射性物探仪器[M].北京:原子能出版社,1987.10.
[10]J.D.Johnson,K.S.Allander,J.A.Bounds,S.E.Garner,J.P.Johnson,D.W.MacArthur and L.Sprouse.Recent Advances of the Electrostatic Long-Range Alpha Detector[J].National Technical Information Service,1994.
[11]http://www.osti.gov/bridge/servlets/purl/10139176-ySpu56/native/10139176.pdf.
[12]高嵩.基于嵌入式PC/104模块的核谱仪系统的研究[D].四川:成都理工大学,2004.