TOTAL NUCLEAR-REACTION PROBABILITY OF 270 TO 390 N-14 IONS IN SI AND CSI

A magnetic spectrograph and position-sensitive detectors were used to measure the total nuclear reaction probability eta(R) for alpha + CsI at 116 MeV, N-14 + CsI at 265 and 385 MeV, and N-14 + Si at 271 and 390 MeV. From these eta(R)'s, average reaction cross sections sigma(R) were deduced for sigma and N-14 on CsI; these agree with optical and strong absorption model predictions. These same models predict sigma(R)'s for N-14 + Si which vary by nearly a factor of 2; our measurement favors the smaller predictions.