x射线衍射图像



【 在 runfast 的大作中提到: 】
: 谁知道真假？
: 如果是真的，谁知道这是什么原子，还有那些花纹是怎么回事儿？[upload=1][/upload]
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FROM 39.149.15.*

钨晶体中的原子照片，放大270万倍

In FIM, a sharp (<50 nm tip radius) metal tip is produced and placed in an ultra high vacuum chamber, which is backfilled with an imaging gas such as helium or neon. The tip is cooled to cryogenic temperatures (20–100 K). A positive voltage of 5 to 10 kilovolts is applied to the tip. Gas atoms adsorbed on the tip are ionized by the strong electric field in the vicinity of the tip (thus, "field ionization"), becoming positively charged and being repelled from the tip. The curvature of the surface near the tip causes a natural magnification — ions are repelled in a direction roughly perpendicular to the surface (a "point projection" effect). A detector is placed so as to collect these repelled ions; the image formed from all the collected ions can be of sufficient resolution to image individual atoms on the tip surface.

Unlike conventional microscopes, where the spatial resolution is limited by the wavelength of the particles which are used for imaging, the FIM is a projection type microscope with atomic resolution and an approximate magnification of a few million times.



“在FIM中，制造锋利(<50nm头端半径)的金属头端，并将其放置在超高真空腔室，其回填有成像气体，例如氦或霓虹灯。尖端冷却至低温(20-100K)。5到10千伏电压应用于尖端气体原子吸附的在尖端被强大的电场在尖端附近(即“场电离”)，变得带正电并被尖端排斥。尖端附近表面的曲率导致自然放大-离子在大致垂直于曲面的方向上被排斥(“点投影”效果)。放置检测器以收集这些排斥的离子；由所有收集的离子形成的图像可以具有足够的分辨率以在尖端表面上成像单个原子。

与传统显微镜不同，其中空间分辨率受用于成像的粒子的波长限制，FIM是具有原子分辨率和近似数百万倍放大率的投影型显微镜。”



【 在 runfast 的大作中提到: 】
: 谁知道真假？
: 如果是真的，谁知道这是什么原子，还有那些花纹是怎么回事儿？[upload=1][/upload]
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修改:snowfields FROM 223.104.153.*
FROM 180.108.128.*

每个亮斑是一个金属原子

Field ion microscope image of the end of a sharp metal needle. Each bright spot is a metal atom.



【 在 runfast 的大作中提到: 】
: 为啥会出现这么漂亮的花纹？
: :
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修改:snowfields FROM 223.104.153.*
FROM 223.104.153.*