A method for determining paper processing parameters using terahertz spectroscopy

To ensure consistency, paper manufacturing requires knowledge of the thickness, areal density, and moisture content of a paper sheet as it is produced. In this thesis, I show that it is possible to use terahertz time-domain spectroscopy to estimate these three parameters. I relate the electromagnetic response of paper to its composition based on an effective medium model that includes an additional term to account for Rayleigh scattering. I show results from Monte Carlo simulations that establish statistical limits on the parameter estimates for this model under realistic conditions, and I assess the performance of the model using experimental results on pulp samples. Finally, I discuss current limitations to the precision of this measurement technique, and suggest methods for improving it.