POPULATION AND DETECTION OF 2-PHONON OCTUPOLE VIBRATIONAL-STATES IN PB-208

We report on an experiment to search for the decay of two-phonon octup ole vibrational states in Pb-208 With GAMMASPHERE. A beam of Sm-154 at a bombarding energy of 1 GeV was used to excite Pb-208 via quasielast ic as well as via deep-inelastic processes. To be independent of the l ifetime of the two-phonon state a thin target was used, requiring the measurement of the position of the scattered particles to correct for the Doppler shift of the emitted gamma rays. Scattered particles were detected by a silicon-strip detector covering forward angles. We did n ot observe any discrete gamma transition in the expected energy range of 2-3 MeV down to a limit of 20% and 4% of the intensity in the 5(-)- ->3(-) transition for quasielastic and deep-inelastic processes, respe ctively.