Status report: direct track detector dosimetry in negative pion beams

Cellulose nitrate and Lexan polycarbonate track detectors have been exposed in a water phantom to 350 Rad in a stopping negative pion beam. The dose is measured at the 'peak' or star region. The vertical beam from the Biomedical Channel at the Los Alamos Medium-Energy Physics Facility (LAMPF) was used. Heavy ions from negative pion interactions in the 'peak' region and 'plateau', or entrance, region were determined by the step etch technique. The ions, and thus the linear energy transfer spectrum from pion interactions with oxygen, have been tentatively identified. The cellulose nitrate track detectors have also been used to measure superficial dose contours of the high LET portion of the peak pion beam in the first human biology trials. These results will be discussed. (Auth.)