EXCITATION OF ISOMERIC STATES IN (GAMMA,N) AND (N,GAMMA) REACTIONS ONEU ISOTOPES

Isomeric ratios were measured for (gamma,n) and (n,gamma) reactions on Eu isotopes, which lie at the boundary between spherical and deformed nuclei. Targets from Eu-151 and Eu-153 were irradiated by thermal neu trons and by bremsstrahlung photons from a microtron with endpoint ene rgies between 13 and 22 MeV. The reactions under investigation resulte d in the excitation of 0(-) and 8(-) isomeric states in Eu-150, Eu-152 , and Eu-154 isotopes. The gamma spectra of product nuclides were meas ured to determine the reaction yields. The effect of quadrupole deform ation on the isomeric ratios is discussed.