Radiation-induced melting in coherent X-ray diffractive imaging at the nanoscale
Radiation-induced melting in coherent X-ray diffractive imaging at the nanoscale
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DOI：
10.1107/s0909049511016335
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发表时间：
2011-07-01
影响因子：
2.5
通讯作者：
Sakata, O.
中科院分区：
文献类型：
--
作者：
Ponomarenko, O.;Nikulin, A. Y.;Sakata, O.
相干X射线衍射技术在从金属和半导体到生物物体的纳米级结构的成像中发挥着越来越重要的作用。在材料科学中，X射线通常被认为具有低破坏性，但在某些条件下，它们会对样品造成显著的辐射损伤和热负荷。有关纳米结构样品在相干衍射成像实验中对同步辐射的耐受性的定性文献数据很少。在这项工作中，聚合物和金纳米样品的同步加速器光束的完全破坏的实验证据报告的情况下，在1-10 nm的空间分辨率成像。基于传热模型的数值模拟表明，样品中的温度分布对宏观实验参数（如材料的传导特性、辐射传热和对流）具有很高的敏感性。然而，对于现实的实验条件下，计算的温度上升率本身不能解释在纳米样品中观察到的熔融转变。将这些结果与文献数据进行比较，可以呈现每个特定情况下样本破坏的具体情况，并提出减少损害的策略。
Coherent X-ray diffraction techniques play an increasingly significant role in the imaging of nanoscale structures, ranging from metallic and semiconductor to biological objects. In material science, X-rays are usually considered to be of a low-destructive nature, but under certain conditions they can cause significant radiation damage and heat loading on the samples. The qualitative literature data concerning the tolerance of nanostructured samples to synchrotron radiation in coherent diffraction imaging experiments are scarce. In this work the experimental evidence of a complete destruction of polymer and gold nanosamples by the synchrotron beam is reported in the case of imaging at 1-10 nm spatial resolution. Numerical simulations based on a heat-transfer model demonstrate the high sensitivity of temperature distribution in samples to macroscopic experimental parameters such as the conduction properties of materials, radiation heat transfer and convection. However, for realistic experimental conditions the calculated rates of temperature rise alone cannot explain the melting transitions observed in the nanosamples. Comparison of these results with the literature data allows a specific scenario of the sample destruction in each particular case to be presented, and a strategy for damage reduction to be proposed.