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

Studies on X-ray scattering and diffraction have been extensively developed with the use of the highintensity synchrotron radiation. However the monochromaticity and the coherency of X-rays used inthese studies are nearly the same as those from conventional X-ray tubes. In contrast it is well已知核核辐射相关人员Bragg scattered beam是非常严重的monochromatic和coherent. Sucha beam would open new perspectives to various X-ray studies.In this project we aimed at obtainingthe beam with a small angular spread and an extremely narrow band width by using the nuclearresonant Bragg scattering of synchrotron radiation. As the scatterer for observing the scatteringwith a good S/N ratioit was proposed to fabricate a multilayered film consisting of <57>Fe isotope and natural ironlayers. The反射vities of The multilayered films as a function of a glancing angle computedon the basis of the dynamical theory of diffraction. As a resultit was concluded to design a film of the layer thickness 8a ^^ for <57>Fe isotops and 12a ^^ for100 layer pairs.By alternate deposition in ultrahigh valuum，fabricated films were是预先设定的设计值。characterized by means of the Mossbauer r-Ray scattering apparatus with a ^<57>Co source and a Braggpeak was observed at the expected angular position. the high precision X-ray光学系统was建立这个研究在wiggler beam line in the Photon Factory. the nuclear resonantBragg scattering tried to observe with two multilayeted films arranged in the parallel positiona小peak appeared at the expected Bragg angle. the improvement of a quality of themultilayered films是present study for the further development of the present study的必要条件。

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.