Micro-Raman spectroscopy as an in situ tool for probing radiation damage during microdiffraction experiments in soft condensed matter

The use of an in situ system for the localized radiation damage in a heterogeneous polypropylene (PP) specimen was investigated. Scanning microdiffraction was carried out at the ID13 microfocus beamline of the ESRF. The beamline was configured for a wavelength of 0.1 nm from a channel-cut Si 111 monochromator. A pair of crossed Kirkpatrick-baez (KB) mirrors provide a spot size at the focal position of 0.9 μm with a divergence of around 1 mrad. The flux was measured using a photodiode. The correlation between the two plot revealed that the 808 cm-1 Raman band position is phase-sensitive. It was observed that the degradation of PP during micro-XRD is dominated by mass loss associated with primary radiation damage. Secondary radiation damage in PP has been linked to accelerated degradation of the amorphous fraction.