Measurement of Neutron Capture Cross Sections of Radio-active Fission Product Nuclides

放射性裂变产物核素中子俘获截面的测量

• 批准号: 03680191
• 负责人: KATOH Toshio
• 金额: $ 1.15万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03680191/
• 关键词: Nuclear Transmutation; Fission Product Nuclide; Activation Method; Neutron Capture Cross Section; Cs-137; Sr-90; Gamma-ray Measurement; Chemical Separation; 長寿命核分裂生成核種; セシウムー137; ストロンチウムー90; ガンナ線スベクトル

Neutron capture cross sections of fission product nuclides were measured to obtain basic data for nuclear transmutation of radio-active waste. There are few data of capture cross sctions of radio-active nuclides since the handling of the radio-active target is difficult.In this study, cross sections were obtained by comparing the activities of a target nuclide and a nuclide produced by the neutron capture process. Activities of both nuclides were measured simultaneously using a large Ge detector.In 1991, the cross section of ^<137>Cs(n,gamma)^<138>Cs reaction was measured. Since the measurement of activities of ^<137>Cs and ^<138>Cs were made simultaneously, various sources of errors such as the counting loss of electronic system and the separation yield of chemical purification process were automatically canceled. The value of cross section obtained was 0.250 * 0.013 barn, and this value is 2.3 times larger than the value reported by Stupegia.In 1992, measurement of the cross section of ^<90>Sr(n, gamma)^<91>Sr reaction was performed by using the same method. The value of cross section obtained was 15.3 * 1.3 mb. The value of resonance using the integral of the ^<137>Cs(n, gamma)^<138>Cs was also measured and the value obtained was 0.36 * 0.07 b. It was found that the effect of resonance integral was negligible.This study presents new and reliable data of neutron capture cross section of ^<137>Cs and ^<90>Sr. The results will be published in Nuclear Science and Technology.

测量了裂变产物核素的中子俘获截面，获得了放射性废物核嬗变的基本数据。由于放射性靶的处理困难，放射性核素的俘获截面数据很少。在本研究中，通过比较靶核素和中子捕获过程产生的核素的活性获得了截面。两种核素的活度用大型锗探测器同时测量。1991年测定了^<137>Cs(n,gamma)^<138>Cs反应的截面。由于同时测量了^<137>Cs和^<138>Cs的活度，自动抵消了电子系统计数损耗和化学净化过程分离率等各种误差来源。得到的横截面值为0.250 * 0.013 barn，是Stupegia报道值的2.3倍。1992年，用同样的方法测量了^<90>Sr(n, gamma)^<91>Sr反应的截面。得到的截面值为15.3 * 1.3 mb。利用^<137>Cs(n, gamma)^<138>Cs的积分也测量了共振值，得到的值为0.36 * 0.07 b。发现共振积分的影响可以忽略不计。本研究提供了^<137>Cs和^<90>Sr中子俘获截面的新可靠数据。研究结果将发表在《核科学与技术》杂志上。

项目成果

Toshiaki SEKINE: "Measurement of the Thermal Neutron Cross Section and Resonance Integral of the Reaction ^<137>Cs(n,γ) ^<138>Cs" Journal of Nuclear Science and Technology.

Toshiaki SEKINE：“热中子截面和反应共振积分的测量^<137>Cs(n,γ)^<138>Cs”核科学与技术杂志。