Dynamic X-Ray Diffractometer

Abstract

The device of a dynamic X-ray diffractometer has been proposed here, principally based on the stroboscope-technique, to be used for observing the X-ray diffraction pattern at a particular phase of periodic deformation of crystalline specimens in a steady state.
This technique is useful not only for determining the crystal lattice deformation and crystal orientation of the specimen under its highspeed periodic deformation, but also for determining the phase difference of the crystal deformation or orientation of the specimen from its bulk strain as a function of vibration frequency at a given temperature and as a function of temperature at a given frequency; i.e., the determination of the relaxation time of crystal deformation or orientation and its temperature dependency.
The result of several experiments made on the crystal orientation of a medium density polyethylene has revealed the fact that the relaxation time of crystal orientation of the polyethylene is of an order of 0.1 sec. at 25°C., which is consistent with the frequency dispersion region of strain-optical coefficient of the polyethylene measured by Onogi et al. by means of the dynamic birefringence technique, and with the time dependent on the phenomena of low-angled light-scattering intensity measured by Erhardt et al. by means of the dynamic light-scattering technique.
This technique may further serve for determining the rates of reversible strain-induced crystallization and reversible strain-induced crystal transitions and the rate of migration of crystal dislocations, twin-boundaries and stacking faults.