摘要
A low-level β counting-or spectrum apparatus used for the detection of the β radiation of thorium-234 and α spectrum of thorium- 228 simultaneously and an easy operating procedure for the enrichment, radiochemical separating, sampling and measurement of thorium-234 and uranium-238 in the ocean are developed based on the requirements of analyzing export productivity in the eupho- ric zone via thorium-234 - uranium-238 radioactivity disequilibrium. The detecting efficiency both of 13 and α radiation is higher than 20%. The background of βradiation is less than 0. 5 min ^-1 , and the energy resolution of ct detector is better than 1%. Total recycle ratio of thorium-234 is about 75%. Using the above apparatus and procedure, the radioactivities of dissolved thorium-234 and uranium-238, particle thorium-234 and uranium-238 in seawater of the South China Sea, the Southern Ocean and the Arctic Ocean were analyzed.
A low-level β counting-or spectrum apparatus used for the detection of the β radiation of thorium-234 and α spectrum of thorium- 228 simultaneously and an easy operating procedure for the enrichment, radiochemical separating, sampling and measurement of thorium-234 and uranium-238 in the ocean are developed based on the requirements of analyzing export productivity in the eupho- ric zone via thorium-234 - uranium-238 radioactivity disequilibrium. The detecting efficiency both of 13 and α radiation is higher than 20%. The background of βradiation is less than 0. 5 min ^-1 , and the energy resolution of ct detector is better than 1%. Total recycle ratio of thorium-234 is about 75%. Using the above apparatus and procedure, the radioactivities of dissolved thorium-234 and uranium-238, particle thorium-234 and uranium-238 in seawater of the South China Sea, the Southern Ocean and the Arctic Ocean were analyzed.
基金
This project was supported by the State Social Commonweal Grant(project name:the comprehensive investigation of Nansha Islands waters)
the Natural Science Foundation of Fujian Province of China under contract No.2006J0287
This study was also supported,in part,by the National Natural Science Foundation of China from key program under contract No.40531007
general program under contract Nos 40406014 and 40276001
State Social Commonweal Grant under contract No.2004DIB5178.
