Marine sediments contamination by fission product 137Cs-137mBa is a fact since the period 1945-65, when plus than two thousand atomic explosion tests were performed mainly in the southern seas, earth region with minor...Marine sediments contamination by fission product 137Cs-137mBa is a fact since the period 1945-65, when plus than two thousand atomic explosion tests were performed mainly in the southern seas, earth region with minor population density. However, marine flows have produced dissemination of this radioactive pair through the sea bottom all over the world, at different levels, because the sea movement and natural decaying of radioactive pair: parent 137Cs (t1/2 = 30.17 years) and daughter 137mBa (t1/2 = 2.55 minutes). Radioactive detection of these contaminants, compared as percentage with that of natural 40K (t1/2 = 1.28 × 109 years, 0.0118% of elementary K) leads to radiation contamination factor (RCF), as one possible unit to measure the radioactive contamination intensity in different regions, as well to determine if there is some other possible source of this contaminant, for example water cooling from power nuclear reactors when it is discharged at sea. However, radioactive detection always implies an unavoidable statistical variation, which makes more difficult to appreciate the changes as function of time and region. But at beginning of this century, mass spectrometry has got impressive advances, which makes it much more precise and sensible than radioactive detection [1]. This paper attempts to measure with other units the radioactive contamination: 137Cs atoms number per gram of sample, instead radioactivity, which could be more direct and with minor standard deviation that radioactive detection, solving at same time the isobars separation: 137Cs versus 137mBa plus elementary 137Ba (11.23% of Ba element).展开更多
The cross sections of long-lived radionuclides of importance in fusionreactor technology are measured by activation method for <sup>137</sup>Ba（n,p）<sup>137</sup>Cs,<sup>182</sup>...The cross sections of long-lived radionuclides of importance in fusionreactor technology are measured by activation method for <sup>137</sup>Ba（n,p）<sup>137</sup>Cs,<sup>182</sup>W（n,n’x）<sup>178</sup>Hf<sup>m2</sup> and <sup>193</sup>Ir（n,2n）<sup>192</sup>Ir<sup>m2</sup> reactions at 14 MeV.The neutron fluencesare determined by the cross sections of <sup>93</sup>Nb（n,2n）<sup>92</sup>Nb<sup>m</sup>,<sup>54</sup>Fe（n,x）<sup>51</sup>Cr and<sup>54</sup>Fe（n,p）<sup>54</sup>Mn reactions.The induced gamma ray activities of the irradiated Ba<sub>2</sub>O<sub>3</sub>,Wand Ir samples and their monitor foils are measured by a calibrated Ge（Li）detector oran anti-Compton gamma ray spectrometer.展开更多
文摘Marine sediments contamination by fission product 137Cs-137mBa is a fact since the period 1945-65, when plus than two thousand atomic explosion tests were performed mainly in the southern seas, earth region with minor population density. However, marine flows have produced dissemination of this radioactive pair through the sea bottom all over the world, at different levels, because the sea movement and natural decaying of radioactive pair: parent 137Cs (t1/2 = 30.17 years) and daughter 137mBa (t1/2 = 2.55 minutes). Radioactive detection of these contaminants, compared as percentage with that of natural 40K (t1/2 = 1.28 × 109 years, 0.0118% of elementary K) leads to radiation contamination factor (RCF), as one possible unit to measure the radioactive contamination intensity in different regions, as well to determine if there is some other possible source of this contaminant, for example water cooling from power nuclear reactors when it is discharged at sea. However, radioactive detection always implies an unavoidable statistical variation, which makes more difficult to appreciate the changes as function of time and region. But at beginning of this century, mass spectrometry has got impressive advances, which makes it much more precise and sensible than radioactive detection [1]. This paper attempts to measure with other units the radioactive contamination: 137Cs atoms number per gram of sample, instead radioactivity, which could be more direct and with minor standard deviation that radioactive detection, solving at same time the isobars separation: 137Cs versus 137mBa plus elementary 137Ba (11.23% of Ba element).
基金IAEA project under Research Agreement No.5060/CF.
文摘The cross sections of long-lived radionuclides of importance in fusionreactor technology are measured by activation method for <sup>137</sup>Ba（n,p）<sup>137</sup>Cs,<sup>182</sup>W（n,n’x）<sup>178</sup>Hf<sup>m2</sup> and <sup>193</sup>Ir（n,2n）<sup>192</sup>Ir<sup>m2</sup> reactions at 14 MeV.The neutron fluencesare determined by the cross sections of <sup>93</sup>Nb（n,2n）<sup>92</sup>Nb<sup>m</sup>,<sup>54</sup>Fe（n,x）<sup>51</sup>Cr and<sup>54</sup>Fe（n,p）<sup>54</sup>Mn reactions.The induced gamma ray activities of the irradiated Ba<sub>2</sub>O<sub>3</sub>,Wand Ir samples and their monitor foils are measured by a calibrated Ge（Li）detector oran anti-Compton gamma ray spectrometer.
