Broadening of a THz pulse as a measure of the porosity of pharmaceutical tablets

THz pulse time delay was measured from ethylcellulose tablets having nominal porosities 13%, 22% and 30%. It is suggested that the observed pulse broadening of sample THz pulse is due to scattering and dispersion of the THz wave in a porous tablet. A parameter related to the pulse broadening is suggested as a sensitive measure for the porosity and porosity change of the tablet.

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