PITSI – Powder Instrument for Transition in Structure Investigations
The PITSI (Sesotho name for Zebra) instrument is located at the SAFARI-1 research reactor of the South African Nuclear Energy Corporation (Necsa) SOC Limited.
It enables medium resolution neutron powder diffraction capability for the study of crystallographic structures, chemical composition and magnetic properties in solid and powdered polycrystalline materials.Neutron powder diffraction complements and extends the capabilities of conventional X-ray diffraction with regard to the following:
- Scattering off nuclei:
- Interaction strength atomic number independent: Sensitivity to light elements and their presence in heavy elements, distinguishing between neighboring elements in 3d, 4f and 5f bands, etc.
- Unlike X-ray diffraction, Neutron diffraction do not suffer form-factor fall off
- Magnetic interaction with unpaired electrons enables studies of magnetic phenomena
- Superior penetrating capabilities enables non-destructive in-situ parametric studies as function of temperature, pressure, magnetic field, chemical exchange of energy-storage materials such as Li batteries, etc.
Resolution of the PITSI instrument measured from Al2O3 powder.
Data reduction and analysis
Data reduction is primarily performed in-house using custom-developed software called ScanManipulator. Data can then be analysed using various products such as Topas, GSAS-2 or Fullprof.
In-situ phase transformation studies to identify and quantify chemical phase and structural parameters.
In-situ magnetic studies to characterise magnetic order, determine phase transitions temperatures, etc.
Chemical phase quantification (Rietveld technique) in multiphase oxides (6 phases in this case). The inset shows the equivalent XRD pattern. Specifically note the presence of high intensities in the small d region (large diffraction angles, up to 120°).
Quantification of retained austenite in heat-treated ferritic steel. The inset shows the equivalent XRD pattern where predominantly only the ferrite peaks are detected.
|Ms. Zeldah Sentsho|
+27 12 305 5918
PITSI is accessible by the scientific community for academic and commercial project proposals.
For more information contact:
Dr Andrew Venter: +27 12 305 5038