Pion production cross-sections and associated parameters

Negative pions have been used for radiotherapy at the meson factories LAMPF (USA), SIN (Switzerland) and TRIUMF (Canada) and have been planned for use at new meson facilities under construction (USSR) and at proposed dedicated medical facilities. Providing therapeutically useful dose rates of pions requires a knowledge of the pion production cross-sections as a function of primary proton energy (500-1000 MeV), pion energy (≤ 100 MeV), production angle and target material. The current status of the database in this area is presented, including theoretical guidelines for extrapolation purposes. The target material and geometry, as well as the proton and pion beam parameters, will affect the electron (and muon) contamination in the beam, which may have an important effect both on the LET characteristics of the dose and the dose distribution. In addition to cross-section data, channel characteristics such as length of pion trajectory, solid-angle acceptance and momentum analysis will affect dose rate, distribution and quality. Such considerations are briefly addressed in terms of existing facilities and proposed systems. (author). 16 refs, 6 figs, 1 tab