Development of Light Detectors for Conversion Electron Mossbauer Spectroscopy and Nuclear Scattering of Synchrotron Radiation

1)阐明了安装在新型穆斯堡尔光谱仪上的快速响应YAP闪烁探测器的特性。2)建立了^<57>Fe穆斯堡尔谐振闪烁移动计数器测量系统。在发射穆斯堡尔光谱（EMS）中，S/N效率为400%。即使是传统光源的1/10放射性，也能以比传统方法更好的能量分辨率测量穆斯堡尔光谱。3)在spring8装置上进行了核共振非弹性散射（NIS）。用8个APD探测器在90 min内获得NIS光谱，时间分辨率小于1ns。该程序是开发的部分声子密度的状态估计从核非弹性散射光谱。在Debye模型的基础上，从态声子密度中得到了不同温度下定量分析必不可少的Lamb-Mossbauer因子。4)测定了（Ba, Sr）（Fe, Co）O_<3-δ>和（Sr, Ca） （Fe,Co）O_<3-δ>钙钛矿的NIS光谱。结果表明，δ=0.5的褐铁矿中存在8 meV声子峰，而钙钛矿中没有。NIS对于分析2mev ~ 60mev状态的振动密度是非常有效的。5)利用研制的转换电子穆斯堡尔探测器，通过选择模具电子能量，对氧化不锈钢的表面和界面进行表征。超细分布分析表明，Cr向表面扩散对铁素体不锈钢的界面有影响。溅射奥氏体不锈钢沉积的不锈钢膜由铁素体相组成。内部磁场因受热而增大。500℃时，铁素体相转变为顺磁奥氏体相。并对不同温度下制备的厚度为10nm的氧化薄膜的状态进行了估计。

1) The properties of YAP scintillation detector with fast response installed into new Mossbauer spectrometer were clarified.2) Measurement system for ^<57>Fe Mossbauer resonant scintillation movable counter, was established. In the emission Mossbauer spectra (EMS), the efficiency of S/N was 400%. Even the 1/10 radioactivity of conventional source could be found to measure Mossbauer spectra with the better energy resolution than a conventional method.3) Nuclear resonant inelastic scattering (NIS) was carried out in SPring 8 facility. It was confirmed that NIS spectra were obtained in 90 min using 8 detectors of APD with less than 1 ns time resolution. The program was developed for partial phonon density of states estimated from the nuclear inelastic scattering spectra. Lamb-Mossbauer factors at various temperatures, which are indispensable for quantitative analysis, were obtained from phonon density of states on the base of Debye model.4) NIS spectra of various perovskite such as (Ba, Sr)(Fe, Co)O_<3-δ> and (Sr, Ca) (Fe,Co)O_<3-δ> were measured. It was found that the phonon peak of 8 meV was observed in brownmillerite with δ=0.5, but not in perovskite. NIS is very effective for analysis of the vibrational densities of states from 2 meV to 60 meV.5) The surface and interface of stainless steel oxidized were characterized by selecting die electron energy using a conversion electron Mossbauer detector developed. It is found from the analysis of hyperfine distribution that the interface of ferrite stainless steel was affected by the diffusion of Cr to the surface. The stainless steel film as deposited by sputtering austenitic stainless steel was consisted of ferritic phase. The inner magnetic fields increased by heating., and the ferritic phase was converted into paramagnetic austenitic phase at 500℃. The states of thin oxide films with 10 nm in thickness produced at various temperatures were also estimated.