2-D elemental mapping of an extreme ultraviolet-irradiated PET with a compact near edge X-ray fine structure spectromicroscopy

Highlights: • a spatially localized NEXAFS spectromicroscopy, • spectromicroscopic images obtained by a raster scan, rather than the energy scan, as is often done using synchrotron radiation • NEXAFS spectrum obtained at once, due to broadband SXR source, simultaneous acquisition of sample and reference spectra for more precise data acquisition and processing. • investigation of polymer degradation by EUV light and quantitative analysis of elemental composition change, • desk top system for NEXAFS analysis with spectral resolution equal to early synchrotron-based research We present a near edge X-ray fine structure (NEXAFS) spectromicroscopy, that was developed based on a compact laboratory laser-plasma soft X-ray light source. The presented approach to spectromicroscopy is different from the usual synchrotron-based one when the series of full-field microscopy images are obtained at different energies. Herein, spatially localized NEXAFS spectra are obtained using a broad-band SXR emission, and the microscopic image is obtained by a raster scanning. The plasma is formed by the interaction of nanosecond laser pulses with a double stream gas puff target. The laser plasma source was optimized for efficient soft X-ray emission from a krypton plasma in the range ~2 nm to 5 nm wavelength radiation (energy of ~250 eV – 620 eV). This emission is used to acquire simultaneously emission and absorption spectra of soft X-ray light from the source and from the investigated sample. The spectra were acquired from a small area of PET polymer ~30 × 30 μm² in size. A raster scanning was implemented to obtain 2-D elemental composition maps. A chemical (elemental) composition of EUV-irradiated PET was investigated. The data are in agreement with the reference measurements and the theoretical values. EUV irradiated PET spectra are showing hydrogen decrease in the PET structure due to the EUV irradiation. In the paper, a detailed information about the source, the system, the spectral measurements and the results are presented and discussed.