X-ray Diffraction (XRD) provides structure and compound identification of single phase and multiphase crystalline materials from intensity versus angle of diffraction scans. Broadening due to crystal size and defects may be studied. In polymer samples, the degree of crystallinity and preferred orientation may be assessed. The XRD laboratory consists of several Philips generators and with vertical diffracted beam monochromators. In addition, a state-of -the-art, computer controlled Rigaku 18KW rotating anode generator coupled to a horizontal diffractometer with a curved crystal monochromator and parallel beam optics is available. This permits in situ studies at elevated temperatures, residual stress measurements on flat or curved surfaces, the determination of the amorphous phase content in a crystalline matrix, glancing angle thin film studies, and precision lattice parameter measurements.
An array of cameras are available for polycrystalline and single crystal studies, with sample spinning accessories and an array of camera attachments (Debye-Scherrer, Gandolfi, Guinier, and Laue cameras) for performing phase characterization of small samples. Detection sensitivity is in the range of 2 % for light element matrices. In addition, for special structure analyses, a high x-ray intensity rotating anode x-ray diffractometer can be applied in the analysis of metals, ceramics, powders and semiconductors. A fully computerized data collection system coupled with search capabilities and the JCPDS-ICDD diffraction database allows for automated phase identification. Other accessories include a high temperature stage (1400 degrees C) for measuring thermal expansion coefficients and phase transformations as a function of temperature. Stress analysis and glancing angle diffraction from near-surface region of solid samples can be carried out as well as the utilization of the Rietveld refinement process for determining the structure of unknown materials.
Rutherford Backscattering Spectrometry – RBS
Located at the University’s Radiation Lab, the RBS provides composition of surfaces and multilayer thin films, nondestructively. The instrumentation is capable of producing a high energy beam of protons (H+), H+2 or alpha particles (He+2) depending upon the particular problem. The helium beam provides superior depth resolution at a reduced sampling depth. The hydrogen beam has an increased sampling depth with reduced depth resolution and may be limited because of the formation of (nuclear) reaction byproducts particularly for the low Z elements. A computer program is available for simulating or modeling the RBS spectrum of the sample, prior to, and after the RBS analysis.
- Ion implanted depth profiles
- Elemental composition of multilayer thin films
- Composition and thickness of interfacial regions