The reflection of X-rays by crystals
The reflection of X-rays by crystals
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DOI：
10.1098/rspa.1913.0040
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发表时间：
1913-07-01
期刊：
影响因子：
--
通讯作者：
Bragg, WL
中科院分区：
文献类型：
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作者：
Bragg, WH;Bragg, WL
在对劳厄照片的讨论中，已经表明，它们可以方便地解释为由于X射线在晶体内富含原子的平面上的反射。这立刻导致了人们试图将解理面用作镜子，并且发现云母从其解理面反射出的铅笔足够强，在几分钟的曝光中就能在照相底片上留下可见的印记。还观察到，可以通过电离方法检测反射的铅笔。为了更仔细地研究X射线的反射，我们使用了一种类似光谱仪的装置，用电离室代替望远镜。准直器被一个铅块所取代，铅块上有一个孔，孔可以向下延伸到各种宽度的狭缝。中间的旋转台上放着水晶。电离室是管状的，15 cm。长5厘米。直径。它可以绕仪器的轴旋转，其自身的轴与仪器的轴垂直。它充满了二氧化硫，以增加电离电流：空气和碘甲烷也偶尔使用，以确保室内气体的特殊特性不会影响结果的解释。直接测量电离电流。由于我们发现不可能将一次射线的适当部分偏转到平衡室中，因此没有使用平衡方法。
In a discussion of the Laue photographs it has been shown that they may conveniently be interpreted as due to the reflection of X-rays in such planes within the crystal as are rich in atoms. This leads at once to the attempt to use cleavage planes as mirrors, and it has been found that mica gives a reflected pencil from its cleavage plane strong enough to make a visible impression on a photographic plate in a few minutes’ exposure. It has also been observed that the reflected pencil can be detected by the ionisation method. For the purpose of examining more closely the reflection of X-rays in this manner we have used an apparatus resembling a spectrometer in form, an ionisation chamber taking the place of the telescope. The collimator is replaced by a lead block pierced by a hole which can be stopped down to slits of various widths. The revolving table in the centre carries the crystal. The ionisation chamber is tubular, 15 cm. long and 5 cm. in diameter. It can be rotated about the axis of the instrument, to which its own axis is perpendicular. It is filled with sulphur dioxide in order to increase the ionisation current: both air and methyl iodide have also been used occasionally to make sure that no special characteristics of the gas in the chamber affect the interpretation of the results. The ionisation current is measured directly. A balance method has not been used as we have not found it possible to deflect a suitable portion of the primary rays into a balance chamber.