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HK: Fachverband Physik der Hadronen und Kerne

HK 19: Structure and Dynamics of Nuclei V

HK 19.5: Vortrag

Dienstag, 12. März 2024, 17:00–17:15, HBR 19: C 5b

First measurement of the lifetime of the 2₁⁺ state of ²⁰⁰Pt — •C.M. Nickel¹, V. Werner¹, P.R. John¹, U. Ahmed¹, C. Costache², K.E. Ide¹, N.M. Mărginean², H. Mayr¹, C. Mihai², R.E. Mihai^2,3, N. Pietralla¹, T. Stetz¹, A. Weber¹, and R. Zidarova¹ — ¹IKP, TU Darmstadt — ²IFIN-HH, Bucharest-Măgurele — ³IEAP, CTU Prague

Shape transitions between oblate, prolate, γ-soft and spherical shapes occur in the region of the W, Os, Pt and Hg isotopes [1]. For the neutron-rich Pt isotopes, the R_4/2 ratio indicates a γ-soft shape
transitioning towards sphericity when approaching the neutron shell closure at N=126. In the vicinity of shell closures, a decrease of quadrupole collectivity is expected. Quadrupole collectivity is quantified by the B(E2;2₁⁺ → 0_gs⁺) transition strength, which is inversely proportional to the lifetime of the 2₁⁺ state. ²⁰⁰Pt is the lightest neutron-rich Pt isotope without a known B(E2;2₁⁺ → 0_gs⁺) value but could mark the transition between a γ-soft and a spherical shape in the Pt isotopic chain. Therefore, the ¹⁹⁸Pt(¹⁸O,¹⁶O)²⁰⁰Pt* two-neutron transfer reaction was studied at the IFIN-HH at Bucharest-Măgurele using the ROSPHERE array equipped with a plunger device and the SORCERER particle detector. After correcting for contaminants and by applying the Recoil-Distance Doppler-Shift method, the lifetime of the 2₁⁺ state of ²⁰⁰Pt was determined for the first time.

[1] Z. Podolyák et al., Phys. Rev. C 79 031305 (2009).

*Supported by the BMBF under Grant No. 05P21RDCI2.

Keywords: 200Pt; Lifetime measurement; RDDS; DDCM; ROSPHERE + SORCERER