Research Research Strands Advanced Imaging

Imaging is a key application of optics and photonics and CAPPA is engaged in a number of advanced imaging activities.  The goal is to gain insight into the structure, form, shape and constituents of the sample under investigation in a non-destructive manner.  The three key techniques that CAPPA employs are:

• Environmental Scanning Electron Microscopy (ESEM)
• Hyperspectral Imaging
• Interferometric & Phase Shift Techniques

Through the use of variable pressure Scanning Electron Microscopy (SEM) non-conducting and water containing samples can be imaged to nanometer resolution.  The SEM imaging can be combined with energy dispersive spectroscopy (EDS) to identify and quantify the element constituents of the sample under test.  Traditionally, nonconductive samples had to be coated prior to SEM imaging and it was not possible to image wet samples at all.  The ability to image nonconductive samples without coating gives CAPPA a great advantage over traditional SEM imaging.  Samples can now be imaged in a nondestructive manner and microanalysis can be performed without the influence of carbon or metal coating.  The chamber size available can also accommodate large and irregularly-shaped specimens.  All this flexibility lends itself to imaging samples in their native state.  This is ideal for gaining insight into product performance under varying environmental conditions as well as understanding the effect of various process steps and parameters.

By extending the spectroscopic capabilities CAPPA can also carry out FT-IR and Raman imaging.  This technique is often termed Hyperspectral Imaging, Spectroscopic Imaging or Chemical Imaging.  This is a powerful combination of FT-IR and Raman Spectroscopy and Microscopy which yields information on the spatial distribution of the spectral properties within a sample.  CAPPA can employ this to investigate the homogeneity of a sample and the distribution of its constituents can be observed.  CAPPA can also investigate the form of a surface through interferometric or phase-shifting techniques which can be design and tailored depending on the sample under test.

All the above techniques have various applications and deployment depending on the sample being investigated and the information required

Details of CAPPA's equipment and facilities can be found here.

Caption – Chemical Imaging of solid dose pharmaceutical tablet displaying the distribution of the Active Pharmaceutical Ingredient in the tablet.