Study of Nuclear Resonant Bragg Scattering of Synchrotron Radiation and Its Application to Crystallography

对X射线散射和干扰的研究已被广泛开发，并以高强度同步加速器辐射的用途。在这些研究中使用的单色性和X射线的相干性几乎和传统X射线管的相同。在对比度下，我们很清楚，因为核共振器布拉格散射的光束是超极高的单色和相干的。这一光束将为各种X射线研究打开新的视角。在这个项目中，我们瞄准了一个小角度扩散的光束，并通过使用核共振器布拉格散射的超窄波段宽度。作为观察散射器，以良好的S/N比率观察散射器，它被提议制造一个由<57>Fe同位素和自然铁层组成的多层电影。The reflectivities of the multilayered films as a function of a glancing angle were computed on the basis of the dynamical theory of diffraction。作为一个结果，它被合并为设计一部多层厚度的电影8A ^^的^<57>Fe同位素和12 A^的100层对天然铁。根据超高值的替代沉积，多层电影根据设计的值准备好了编码。制造的电影是由Mossbauer r-Ray散射装置的特征化的，带有a ^<57>Co源的，而一个布拉格峰值则被观察到在预期的角度位置。高精度X射线光学系统是在光子工厂的威格勒光束线上建造的。“核共振布拉格散射”曾尝试在平行位置放置两部多层电影，并在预期的布拉格角出现了一个小峰值。对多层次电影质量的改进是对当前研究的进一步发展的必要性。

Studies on X-ray scattering and diffraction have been extensively developed with the use of the high intensity synchrotron radiation. However the monochromaticity and the coherency of X-rays used in these studies are nearly the same as those from conventional X-ray tubes. In contrast it is well known that the nuclear resonant Bragg scattered beam is ultrahighly monochromatic and coherent. Such a beam would open new perspectives to various X-ray studies.In this project we aimed at obtaining the beam with a small angular spread and an extremely narrow band width by using the nuclear resonant Bragg scattering of synchrotron radiation. As the scatterer for observing the scattering with a good S/N ratio, it was proposed to fabricate a multilayered film consisting of ^<57>Fe isotope and natural iron layers. The reflectivities of the multilayered films as a function of a glancing angle were computed on the basis of the dynamical theory of diffraction. As a result, it was concluded to design a film of the layer thickness 8 A^^゜ for ^<57>Fe isotops and 12 A^^゜ for natural iron with 100 layer pairs.By alternate deposition in ultrahigh valuum, the multilayerd films were prepared according to the designed values. The fabricated films were characterized by means of the Mossbauer r-Ray scattering apparatus with a ^<57>Co source and a Bragg peak was observed at the expected angular position. The high precision X-ray optical system was constructed for this study at the wiggler beam line in the Photon Factory. The nuclear resonant Bragg scattering was tried to observe with two multilayeted films arranged in the parallel position and a small peak appeared at the expected Bragg angle. The improvement of a quality of the multilayered films is necessary for the further development of the present study.