FIZIKA B 7 (1998) 1, 37-54

CASCADE GAMMA-DECAY PROCESS OF THE ¹⁷⁷Lu COMPOUND NUCLEUS AND ITS PECULIARITIES

VALERY A. KHITROV^a, ANATOLY M. SUKHOVOJ^a, JAROSLAV HONZÁTKO^b, IVO TOMANDL^b and GEORGY GEORGIEV^c

^a Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia
^b Nuclear Physics Institute, CZ-25068 Řež near Prague, Czech Republic
^c Institute for Nuclear Research and Nuclear Energy, 1784 Sofia, Bulgaria

Received 12 June 1997; revised manuscript received 15 October 1997;Accepted 15 June 1998

From the mass of g-g coincidences registered by a pair of Ge-detectors after thermal neutron capture in ¹⁷⁶Lu, the intensity distributions of the two-step cascades proceeding between the compound state and eight low-lying ( 122 Ł E_ex Ł 637 keV) levels of ¹⁷⁷Lu were obtained. The analysis of the intensity distribution of all the cascades resolved experimentally and of the total distribution, including unresolved cascades, showed that the correct description of the cascade g-decay process for the odd-even deformed nucleus should account for the strong influence of vibrational-type excitations below 3 MeV and an abrupt transition from vibrational to quasiparticle excitations above this energy.

PACS numbers 25.40.Lw, 27.70.+q, 27.60.+j
UDC 539.172.4

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