The lattice parameter of a perfect silicon single crystal was determined by using a modification of Bond's method and a precise double crystal X-ray spectrometer. An up-to-day version of the double crystal spectrometer theory, based on the dynamical theory of X-ray diffraction, was employed.Der Gitterparameter eines perfekten Silizium-Einkristalls wurde mit einer modifizierten Bondmethode und mittels eines prazisen Doppel-Kristall-Rontgenspektrometers bestimmt. Dabei wurde eine neue Version der Theorie des Doppelkristallspektrometers, die auf der dynamischen Theorie der Rontgenbeugung basiert, benutzt.

A polychromatic X‐ray beam has been scattered at polycrystalline samples and the energy distribution of X‐rays diffracted under a fixed angle, 2 θ, was measured by means of semiconductor spectrometer with a Si(Li) detector. Under these conditions the X‐ray pattern is obtainable in a few minutes. The resolution of the spectrometer was about 1 keV. Good agreement between the calculated and observed positions of diffraction peaks for Al, Cu, Pt, and Au foils as well as for a powdered Si sample was obtained. For the Si sample a comparison of the observed and calculated intensities was made and good agreement was obtained.

An X-ray study is made of a single crystal of Si after irradiation by protons of energy N _ 6.5 MeV, the total dose being 1 to 2 x protons/cm2. An increase of the lattice parameter: d a _N + 3 x A is observed after bombardment. The atomic planes in the bombarded part of the Si crystal are tilted, making an angle of 1.7" with planes of the unbombarded part. An imperfection in the diamond-type structure is found as confirmed by diffraction from the (222) planes. Ein Si-Kristall wurde nach Bestrahlung mit Protonen rontgenographisch untersucht. Die Protonenenergie betrug etwa 6,5 MeV und ihre Gesamtdosis 1 bis 2.10" Protonen/cm2. Nach der Bestrahlung wurde eine Zunahme der Gitterkonstante von d a A beobachtet. Die Netzebenen in dem bestrahlten Teil des Si-Kristalls waren urn einen Winkel von etwa 1,7" gegen die Netzebenen der unbestrahlten Teils gedreht. Eine Storung der Diamantstruktur konnte durch das Vorhandensein der (222)-Interfrenz festgestellt werden.

A dislocation free silicon single crystal, cut parallel to the (111) plane, has been implanted with 4.1 MeV &-particles at the dose % 10l6 t d c m in the [ill] direction and investigated with a precise X-ray double crystal spectrometer (1) and a Berg-Barrett camera. 2 Change of the crystal lattice parameter A series of CuKa X-ray topographs (3, -3), for the (111) plane and symmetrical Bragg case were taken at different positions of the crystal obtained by its rotation about the horizontal axis perpendicular to the crystal surface. The topographs of the implanted sample reveal an increase of the lattice parameter dbeam the reflection from the implanted part of the crystal occurs always at the lower angle 8 than that from the unimplanted one. Fig. 1 represents one of these topographs taken at half-height of the maximum at the side of lower angle I 3 .since at any crystal position to the X-ray

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