A combination of two independent imaging area-detector systems control
led by a single data-acquisition system, provides a powerful system fo
r X-ray diffraction studies of time-resolved phenomena over a wide q r
ange, in samples with intrinsic or induced structural orientation. Wit
h this system we have observed a transient, tensile-stress-induced, or
thorhombic-to-monoclinic transition in high-density polyethylene.