Question

A convergent beam is obtained by placing which of the following material between the X-ray source and the sample?

(a) Soil particles

(b) Single crystal of carbon

(c) Linear double crystal of graphite

(d) Bent single crystal of quartz

I had been asked this question in exam.

This is a very interesting question from The X-ray Diffraction Experiment topic in portion X-Ray Diffraction of Solid State Chemistry

Answer 1

Right choice is (d) Bent single crystal of quartz

For explanation: Convergent beam is obtained by placing a bent single crystal of quartz or graphite between the X-ray source and the sample. The orientation of this bent crystal is adjusted so that it diffracts the incident beam and converts it from the divergent beam into a convergent one.