The optimum conditions to collect X-ray data from very small samples
The optimum conditions to collect X-ray data from very small samples
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DOI：
10.1107/s0909049508014623
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发表时间：
2008-09-01
影响因子：
2.5
通讯作者：
Nave, Colin
中科院分区：
文献类型：
--
作者：
Cowan, John A.;Nave, Colin
先前的论文[Nave & Hill（2005）J. Synchrotron Rad. 12 299-303]研究了在光电子可以从样品中逃逸的条件下减少小晶体（尺寸为10 μ m及以下）的辐射损伤的可能性。这篇论文的结论是，较高能量的辐射（例如40 keV）可以提供一个优势，因为光电子路径长度更长，晶体中沉积的能量更少。本文进一步改进了这些计算，包括由于康普顿散射和入射光子和发射的光电子之间的能量差的能量沉积的影响。给出了从给定大小和组成的蛋白质晶体收集数据的最佳波长的估计。减少蛋白质晶体辐射损伤的另一种方法是用非常短的脉冲X射线源收集数据，其中可以在随后的辐射损伤发生之前获得单个图像。这种方法相比，使用较短的波长进行了比较。
A previous paper [Nave & Hill (2005) J. Synchrotron Rad. 12 299-303] examined the possibility of reduced radiation damage for small crystals (10 Pm and below in size) under conditions where the photoelectrons could escape from the sample. The conclusion of this paper was that higher-energy radiation (e.g. 40 keV) could offer an advantage as the photoelectron path length was greater and less energy would be deposited in the crystal. This paper refines these calculations further by including the effects of energy deposited owing to Compton scattering and the energy difference between the incident photon and the emitted photoelectron. An estimate is given for the optimum wavelength for collecting data from a protein crystal of a given size and composition. Another way of reducing radiation damage from a protein crystal is to collect data with a very short pulsed X-ray source where a single image can be obtained before Subsequent radiation damage occurs. A comparison of this approach compared with the use of shorter wavelengths is made.