sinθ=nλ2d

ompared to film, scintillationcounter can measure diffraction intensities and Bragg angles more accurately.

The film is placed around the sample as a circle and records the diffracted X-ray beams. The positions of diffraction lines correspond to Bragg angle. And Photographic film can record both the reflected and transmitted X-ray beams.

It is usually made of single crystal silicon.

Usually, evenly grinded sample powder is dissolved in organic solvent such as acetone or pressed into a plain on a glass slide to make sure the sampel is flat. The sample holder has a press ring to fix the slide.

f Be is close to zero, so it can make sure the X-ray source is monochromatic and does not contain introduced chracteristic X-rays from other metals.

In a reflection geometry instrumentation, X-ray tube usually contains a side window made of Be to allow the generated X-rays to emit at the demanding angle. The reason that Be is used as a X-ray window, is that the fluorescence yield

Powder X-ray diffractometer consists of three components: X-ray source, sample holder and detector.

Body centered, I hkl: h+k+l=2n Face centered, F hkl: h, k, l either all odd or all even

Primitive, P None

The n-type semiconductor is coated by an aluminum contact

ne. The semiconductor is usually composed of silicon; germanium

In a scintillation counter, a phosphor is placed in front of a photomultiplier tube.

A powder X-ray diffractometer consists of an X-ray source (usually an X-ray tube), a sample stage, a detector and a way to vary angle θ.

In powder X-ray diffraction, the diffraction pattern is obtained from a powder of the material, rather than an individual crystal. Powder diffraction is often easier and more convenient than single crystal diffraction since it does not require individual crystals be made.

Bragg’s Law nλ=2dsinθ(1)(1)nλ=2dsin⁡θn\lambda = 2d\sin\theta where: λλ\lambda is the wavelength of the x-ray, ddd is the spacing of the crystal layers (path difference), θθ\theta is the incident angle (the angle between incident ray and the scatter plane), and nnn is an integer

Bragg’s Law was introduced by Sir W.H. Bragg and his son Sir W.L. Bragg. The law states that when the x-ray is incident onto a crystal surface, its angle of incidence, θθ\theta, will reflect back with a same angle of scattering, θθ\theta. And, when the path difference, ddd is equal to a whole number, nnn, of wavelength, a constructive interference will occur.