Radium-224 activities in the western Arctic Ocean were measured viaship-board ^(220)Rn emanation technique during the Second Chinese National Arctic Expedition. Theresults showed that the ^(224)Ra activities in the st...Radium-224 activities in the western Arctic Ocean were measured viaship-board ^(220)Rn emanation technique during the Second Chinese National Arctic Expedition. Theresults showed that the ^(224)Ra activities in the study areas ranged from being less than 0.08 to3.58 Bq/m^3, with an average of 0.23 Bq/m^3. The low ^(224)Ra concentration in the surface water wasattributed to the influence of sea ice melted water. The horizontal distribution of surface^(224)Ra in the western Arctic Ocean showed a high ^(224)Ra characteristics occurred along the slopearound 160°W, providing evidence for the importance of ice-rafted sediments to controlling thedistribution of radium isotopes in the Arctic Ocean. Mostly, ^(224)Ra concentrations increased withthe depth in the shelf region and reached a maximum at 75 m at the central Canada Basin, whichfurther confirms the importance of the transport of shelf bottom water to maintaining the upperhalocline layer in the Canada Basin.展开更多
本文介绍了测量海水中224Ra和223Ra比活度的国际通用仪器镭延迟符合计数器(Ra De CC),该仪器具有效率高、灵敏度高、背景值低、方便携带和适合海上现场测量等优点。结合本实验室3 a使用经验和工作数据,对仪器测量误差、探测效率、本底...本文介绍了测量海水中224Ra和223Ra比活度的国际通用仪器镭延迟符合计数器(Ra De CC),该仪器具有效率高、灵敏度高、背景值低、方便携带和适合海上现场测量等优点。结合本实验室3 a使用经验和工作数据,对仪器测量误差、探测效率、本底值和探测限等做出系统的阐述和讨论。结果表明,Ra De CC对224Ra和223Ra的探测效率分别在0.47~0.59和0.45~0.57之间,探测限分别为0.04 dpm和0.01 dpm,对224Ra和223Ra测量的相对标准偏差一般在5%和15%左右,但是,当224Ra比活度低于5 dpm/100 L时,变异系数将升高至10%~30%;当223Ra低于0.3 dpm/100 L时,变异系数将高达20%~80%。展开更多
基金supported by Program for New Century Excellent Talents in University of China under contract No.NCET-04-0593Chinese Second Arctic Expedition Foundation.
文摘Radium-224 activities in the western Arctic Ocean were measured viaship-board ^(220)Rn emanation technique during the Second Chinese National Arctic Expedition. Theresults showed that the ^(224)Ra activities in the study areas ranged from being less than 0.08 to3.58 Bq/m^3, with an average of 0.23 Bq/m^3. The low ^(224)Ra concentration in the surface water wasattributed to the influence of sea ice melted water. The horizontal distribution of surface^(224)Ra in the western Arctic Ocean showed a high ^(224)Ra characteristics occurred along the slopearound 160°W, providing evidence for the importance of ice-rafted sediments to controlling thedistribution of radium isotopes in the Arctic Ocean. Mostly, ^(224)Ra concentrations increased withthe depth in the shelf region and reached a maximum at 75 m at the central Canada Basin, whichfurther confirms the importance of the transport of shelf bottom water to maintaining the upperhalocline layer in the Canada Basin.
