Dear Shyam Kumar ,

you are right; there is mainly the same outcome...

Angular dispersive x-ray diffraction (ADXRD) is mainly*) used in synchrotron applications. Here 1D- or 2D-detectors are in operation gathering the XRD pattern or the Debye-Scherrer rings respectively. The data acquisition is done for all pixels almost simultaneously. A time consuming step by step acquisition, as it is done in the theta-2theta scans in 'normal' goniometer based XRD, is avoided here.

Thus ADXRD in combination with the high x-ray photon flux of the synchrotron beam line enables time resolved acquisition of XRD pattern with low time constant.

*) there are also some ADXRD applications with tubes as x-ray light sources

Best regards

G.M.

In my experience GM is always right, but I would think that ADXRD is the common way of using a specific wavelength and varying angle to give varying d. Doesn't matter if data is collected over a range of angles by using a 1-D or 2-D detector or by moving the detector, either way that is AD. That it is angle dispersive would usually only be specified in contrast to energy dispersive (EDXRD). EDXRD uses a wide range of incident energies and an energy-resolving detector (at a known angle) to determine various d. This usually has lower resolution but can be quick and use equipment with no moving parts.

What do you think, G.M.?

Dear Shayma Kumar

While XRD is a versatile and commonly used technique for determining the crystal structure of materials, ADXRD is required in cases where higher precision, resolution, and sensitivity are needed. ADXRD is often employed in research involving complex materials, thin films, and high-pressure studies, where detailed structural information is crucial and traditional XRD methods may fall short.

w.s.l. Boyer ,

you are right, also the 'normal' goinometer based XRD is an angle dispersive one. The mapping of the 'intensity scale onto the angular scale is done by the goniometer, which moves the 0D-detector along the angular (2theta) direction in step by step or continous moving mode. But all that is time consuming.

Angular dispersive set-ups using 1D or 2D detectors avoid such time consuming acquisition.

Energy dispersive acquisition (EDXRD) dealing with broad band sources (synchrotron or bremsstahlung of x-ray tube) and energy resolving detectors (HpGe, Si or CdTe) is an alternative, but, as you aready mentioned, the peak resolution is the critical issue here. The peak resolution in EDXRD is governed by the angular resolution (or better the divergence) of the primary beam and that of the diffracted beam as well as the energy resolution of the detector. Whereas the angular divergence(s) can be chosen to be very small (by appropriate long distances*)), the energy resolution is fixed due to the detector properties and thus limits the peak resolution of EDXRD (being quite poor compared 'normal' XRD)

*) it is quite clear, that long distances (due to the r-2 law) will bring down the net photon flux at the detector very quickly and thus should be avoided...

Best regards

G.M.