RADIOISOTOPE YIELDS FROM 1.85-GEV PROTONS ON MO AND 1.85 AND 5.0-GEV PROTONS ON TE

Radioisotope yields from 1.85-GeV proton interactions in a natural iso topic composition Mo target and those from 1.85- and 5.0-GeV protons i n natural Te targets were measured at Lawrence Berkeley National Labor atory's Bevatron. The radioisotope yields were determined by gamma-cou nting the targets using 100-cm(3) coaxial Ge detectors following the i rradiations. Cross sections were determined for the production of 36 r adioactive nuclides, ranging from Z=35, A=74 to Z=43, A=97, from the M o target and for 43 radioactive nuclides, ranging from Z=35, A=75 to Z =53, A=130 from the Te targets. The average deviations of the experime ntal cross sections from those predicted by the semiempirical isotopic cross sections of Silberberg and Tsao were 53% for p+Mo at 1.85 GeV, 66% for p+Te at 1.85 GeV, and 35% for p+Te at 5.0 GeV. These deviation s are higher than those found previously for medium and heavy targets and for elemental cross sections. The minimum production cross section of Nb-91, which may be of interest as a cosmic-ray chronometer, was f ound to be 18+/-3 mb for the p+Mo reaction.