Products of stopped-pion interactions with Cu and Ta

Abstract

Yields of radioactive products from the interactions of stopped ${\ensuremath{\pi}}^{\ensuremath{-}}$ with Cu and Ta have been measured. Absolute yields of products ranging down to ${10}^{\ensuremath{-}5}$ per stop were determined. The experimental yields are compared with yields calculated with a model that was developed in this work for the stopped-${\ensuremath{\pi}}^{\ensuremath{-}}$ interaction. The calculations give excellent agreement with measured total mass yields for Ta, but some discrepancies exist for the independent yields of Hf, Er, and Tm isotopes; in the case of Cu, most independent yields, except for Co and Sc, are in good agreement. Measurements were also made with both stopped ${\ensuremath{\pi}}^{\ensuremath{-}}$ and 20-MeV ${\ensuremath{\pi}}^{+}$ on Cu and Fe to determine the shift in the centroids of the isotopic yields with pion charge.NUCLEAR REACTIONS Stopped-negative-pion interactions with Cu and Ta. Measured yields of residual radioactive products. Calculated yields from model for the interactions.