Preparation and Applications of Neutron Storage Bottle with Ultrafine Polished Metal Mirrors

1.为研究中子β衰变的物理性质，优化设计了一个超冷中子贮存瓶。研制了一台衰变粒子谱仪，并阐明了谱仪的特性。2.为了制备最佳的中子衰变储存瓶，研究了金刚石表面加工和电化学表面抛光等金属表面处理的最高技术。3.金刚石表面加工保持了加工图形的表面结构，不适用于不锈钢等硬质材料，而电化学表面抛光适用于大表面积硬质材料的超高精度抛光。这些进展在KURRI-KR-14（1997）中报道。5.根据这些研究进展，采用电化学超高功率处理方法制备了高质量的不锈钢反射镜。反射率研究的测量结果提供了关于电抛光和化学抛光工艺的最佳组合的信息。6.在此基础上，对衰变瓶的中子贮存性能进行了数值分析，并制备了直径50 cm、长60 cm的圆柱形、切向注入的不锈钢衰变瓶。7.所制备的瓶子与KUR超镜中子涡轮机装置相连，用于瓶子特性研究和进一步应用于中子物理实验。

1.An ultracold neutron storage bottle was designed with optimization for the studies on physical propeties of neutron beta decay. A decay particle spectrometer was developed and the characteristics were clarified. These results were published in J.Phys.Soc.Japan, Suppl.A.2.In order to prepare the best storage bottle for neutron decay experiments, the highest technologies of metal surface treatments were studied on thediamond surface working and the electro-chemical surface polishing.3.As the results, the diamond surface working remains surface structure of working patters and not applicable to hard materials such as stainless steel, while the electro-chemical surface polishing is applicable to ultra-high precision polishing on a large surface area of hard materials. These developments were reported in KURRI Progress Report 1996 and the Scientific Meeting in the Research Reactor Institute.4.A new important approach was developed on the theoretical expression of the total reflection of bottle mirrors, and the approach was reported in KURRI-KR-14(1997).5.According to these research developments, high quality stainless steel mirrors were prepared by the electro-chemical ultra-high treatments. The meaured results of the reflectivity studies gave informations on the best combination of the electic and chemical polishing processe. The results of these studies were reported on a publication "Hamon" 7(1997).6.Based on the results of these studies, numerical analyzes on the neutron storage properties of decay bottles were carried out, and a cylindrical shape, tangential injection, 50 cm diameter and 60 cm lenght stainless steel bottle was prepared. The developments of these bottle arrangements were presented in the Workshop JHP'98 held at KEK,Tsukuba.7.The bottle prepared was connected to KUR supermirror neutron turbine facility for the experiments of bottle characteristics studies and further applications to neutron physics experiments.