Resonances in odd-odd ¹⁸²Ta

¹ Physics Department, Stellenbosch University, Merriman avenue, Stellenbosch 7600, South Africa
² Department of Nuclear Physics, iThemba LABS, PO Box 722, Somerset West 7129, South Africa
³ Department of Physics, University of Oslo, 0316, Oslo, Norway
⁴ Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore 94551, California, USA
⁵ Helmholtz Institute Mainz, 55099 Mainz, Germany
⁶ GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
⁷ Physics Department, University of Western Cape, Modderdam Road, PO Box X17, Bellville 7530, South Africa

Published online: 13 September 2017

Abstract

Enhanced γ-decay on the tail of the giant electric dipole resonance, such as the scissors or pygmy resonances, can have significant impact on (n,γ) reaction rates. These rates are important input for modeling processes that take place in astrophysical environments and nuclear reactors. Recent results from the University of Oslo indicate the existence of a significant enhancement in the photon strength function for nuclei in the actinide region due to the scissors resonance. Further, the M1 strength distribution of the scissors resonances in rare earth nuclei has been studied extensively over the years. To investigate the evolution and persistence of the scissor resonance in other mass regions, an experiment was performed utilizing the NaI(Tl) γ-ray detector array (CACTUS) and silicon particle telescopes (SiRi) at the University of Oslo Cyclotron laboratory. Particle-γ coincidences from the ¹⁸¹Ta(d,p)¹⁸²Ta and ¹⁸¹Ta(d,d')¹⁸¹Ta reactions were used to measure the nuclear level density and photon strength function of the well-deformed ¹⁸¹Ta and ¹⁸²Ta systems, to investigate the existence of resonances below the neutron separation energy.