Spallation of Cu byπ−across theT=12resonances and at high energy

Abstract

Relative yields of 11 selected products ($^{24}\mathrm{Na}$, $^{43,44,46,47,48}\mathrm{Sc}$, $^{55,56,57,58,60}\mathrm{Co}$) have been measured for the interaction of 0.6- and 0.9-GeV negative pions with Cu. In addition, the yields of $^{24}\mathrm{Na}$ and $^{58}\mathrm{Co}$ from Cu have been measured for 12-GeV ${\ensuremath{\pi}}^{\ensuremath{-}}$. Results at the two lower energies which correspond to the first two isospin $T=\frac{1}{2}$ pion-nucleon resonances are compared with earlier studies of Cu spallation by ${\ensuremath{\pi}}^{\ensuremath{-}}$ at energies across the first $T=\frac{3}{2}$ resonance, i.e., 50 to 350 MeV. The 12-GeV ${\ensuremath{\pi}}^{\ensuremath{-}}$ results are compared with similar investigations in which both energetic protons and heavy ions were used. For ${E}_{\ensuremath{\pi}}\ensuremath{\ge}0.5$ GeV no evidence of strong resonance effects can be found in the pattern of the spallation yields. As the pion energy is raised a smooth trend of enhanced yields of deep spallation products to near-target yields closely parallels the same trend observed for both high-energy proton and heavy-ion spallation of Cu. These results indicate that at high energy, pi-mesic spallation exhibits the same features of limiting fragmentation and factorization of the isotopic yields that have been observed previously in hadron induced spallation.NUCLEAR REACTIONS Cu(${\ensuremath{\pi}}^{\ensuremath{-}}$, spallation), ${E}_{\ensuremath{\pi}\ensuremath{-}}=0.6, 0.9, \mathrm{and} 12$ GeV, measured relative $\ensuremath{\sigma}(A,Z)$, 11 selected products $^{24}\mathrm{Na}$-$^{60}\mathrm{Co}$. Comparison with high-energy proton and heavy-ion spallation of Cu. Natural targets, Ge(Li) detectors.