Investigating the intruder states of 83 Se via lifetime measurements

• Published in: Journal of physics. Conference series 2023-09, Vol.2586 (1), p.12052
• Main Authors: Pellumaj, J., Gottardo, A., Goasduff, A., Bazzacco, D., Brugnara, D., Bottoni, S., Capra, S., de Angelis, G., Gozzelino, A., Ha, J., Lenzi, S.M., Marchi, T., Menegazzo, R., Mengoni, D., Nannini, A., Napoli, D.R., Pérez-Vidal, R.M., Pigliapoco, S., Recchia, F., Rezynkina, K., Valiente-Dobón, J.J., Zanon, I., Ziliani, S., Zhang, G., Carturan, S., Loriggiola, M.
• Format: Article
• Language: English
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/2586/1/012052

Quadrupole interaction involving protons and neutrons drives the nucleus into deformed configurations at low excitation energies. Intruder states appear in N=49 isotones, reaching a minimum at around 500 keV in 83 Se. Since 83 Se is in the mid of the proton shell (Z=28-40), it is a good candidate to study the properties of particle-hole intruder states lowered in energy by large quadrupole correlations. Moreover, it will also allow one to estimate the degree of N=50 core breaking in the ground state of Se isotopes. The lifetime of the 540-keV 1/2 + state and 1100-keV 3/2 + state of 83 Se were measured using the Recoil Distance Method and the Doppler Shift Attenuation Method respectively. A beam of 82 Se, with intensity 0.02 pnA, accelerated to 270 MeV from the Tandem accelerator at LNL-INFN, was sent into a deuterated polyethylene foil (C 2 D 4 ), evaporated on a 6 mg/cm 2 gold layer. The GALILEO γ-array was coupled to the SPIDER silicon array, allowing one to obtain the needed channel selectivity through particle-γ coincidence measurements.