(π+-, xn) reactions

Cross sections for the formation of the 76Ge(π+,xn)/sup 76-x/As and the 76Se(π-,xn)/sup 76-x/As reaction products were determined for values of x up to six for both 100 and 180 MeV pions. The π- induced cross sections were consistently higher than those induced by π+ for all nonzero values of x. Both the π- and π+ induced cross sections appear to reach a maximum value when x equals 2 or 3. The results are compared to predictions based on cascade-evaporation calculations and discussed in terms of possible mechanisms. Combining the experimental results for x=5 and 6 with these calculations it was concluded that no significant difference exists in the excitation energy spectrum following π+ or π- interaction