Abstract
This project was undertaken to measure the relative numbers of -ve pions captured onto carbon, nitrogen and oxygen in a number of mostly organic compounds. The results have been used to investigate the validity of the Fermi Teller law. Dosimetry calculations, currently being used to plan -ve pion radiotherapy treatment, are based on the predictions of this law. Results from this experiment show it to be incorrect for organic molecules. The results have also been used to guide the development of a previously existing molecular model of pion capture. A cascade calculation has been undertaken in order to gain further insight into the pionic capture and cascade processes and to determine whether or not certain processes, neglected for the purposes of the capture ratio calculation, were truly negligible.