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Development of supermirror neutron guide tube and its applications to slow neutron physics

超镜中子导管研制及其在慢中子物理中的应用

基本信息

批准号：
56420061
负责人：
OKAMOTO Sunao
金额：
$ 15.1万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1981
资助国家：
日本
起止时间：
1981 至 1985
项目状态：
已结题

项目摘要

1. The computer controled vacuum-deposition technique is developed to make multilayer mirrors of nickel and titanium within the accuracy of a few <゜]A> . To get the critical wavelength <lambda_c> =240 <゜]A> (normal component to the mirror), 185 layers are alternately deposited on the float glass of 6cm thick. The reflectivity of the mirror is found to be 0.85 on the average to neutrons of wavelength shorter than 580 <゜]A> , <lambda_c> of a single nickel mirror.2. The super-mirror neutron guide tube is constructed at the B-4 beam hole in the KUR by connecting 13 elements with the use of a special equipment for ajusting the curve, twist and perpendicularity of mirrors, so that the neutron loss due to the abutment error is less than 1%. It is 11.7 m in length, with the cross section of 10mmx74mm.3. The total neutron flux is measured as about 5x <10^7> n/ <cm^2> sec on the average at the exit of the guide tube. It is about 20 times as large as that at the nickel mirror guide tube installed at the E-3 beam hole. To reduce the leakage dose-rate to less than 0.5 mr/hr in the reactor room, special shieldings made of heavy concretes, <B_4> C and Li-tiles are manufactured.

1.研制了计算机控制的真空镀膜技术，用于制作精度在几埃以内的镍钛多层膜反射镜。为了获得临界波长<lambda_c>=240埃（垂直于反射镜的分量），在6cm厚的浮法玻璃上交替沉积185层。实验结果表明，单个镍镜对波长小于580埃的中子的平均反射率为0.85<lambda_c>.在KUR的B-4束流孔处，用13个单元连接，用专用设备调整反射镜的弯曲度、扭曲度和平直度，建造了超反射镜中子导管，使对接误差引起的中子损失小于1%。长11.7米，断面10 mmx 74 mm。3.在导管出口处测得的总中子通量平均约为5 × 10 ^7> n/ <cm ^2> sec。它大约是安装在E-3束孔处的镍镜导管处的20倍。为了将反应堆室内的泄漏剂量率降低到0.5 mr/hr以下，制造了由重混凝土、<B_4>C和Li瓷砖制成的特殊屏蔽。