IRIS & ISOLDE: laser ion source

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Edgar Ellis
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1 IRIS & ISOLDE: laser ion source ЭКСПЕРИМЕНТЫ С ЛАЗЕРНЫМ ИОННЫМ ИСТОЧНИКОМ A. E. Барзах, П. Л. Молканов, М. Д. Селиверстов, Д. В. Федоров,

2 Windmill-ISOLTRAP-RILIS collaboration PNPI, Gatchina, Russian Federation RILIS and ISOLDE, Geneva, Switzerland Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz, Germany University of Manchester, UK team University of the West of Scotland, United Kingdom Instituut voor Kern- en Stralingsfysica, K.U. Leuven, Leuven, Belgium Comenius University, Bratislava, Slovakia University of York, United Kingdom IS 456, 466, 511, 534, 598, 608

3 ISOLDE: in-source spectroscopy B. A. Marsh et al., EMIS conference, NIM B317, p.550 (2013) WM: A.N. Andreyev et al, Phys. Rev. Lett 105, (2010) MR ToF MS: R. N. Wolf et al, NIM, A686, 82 (2012)

4 ISOLDE: in-source spectroscopy B. A. Marsh et al., EMIS conference, NIM B317, p.550 (2013) WM: A.N. Andreyev et al, Phys. Rev. Lett 105, (2010) MR ToF MS: R. N. Wolf et al, NIM, A686, 82 (2012)

5 Hg: Shape staggering? The huge shape staggering in light Hg isotopes is one of the most remarkable discoveries in nuclear structure physics in the last 50 years. K. Heyde and J. L. Wood, Phys. Scr. 91 (2016) G. Ulm, S.K. Bhattacherjee, P. Dabkiewicz, et al., Z. Phys. A 325, (1986)

6 Hg: End of the shape staggering 177 Hg yield ~ 1 nuclide per 100 s End of the shape staggering! New theoretical explanation of the shape evolution was proposed to describe our data

7 ISOLDE: End of the shape staggering

8 Shape staggering: Theory, HF Nuclear Density Functional Theory (DFT) Potential Energy Surface Circles: oblate, diamonds : weekly prolate, Squares: strongly prolate minima Wrong I and μ!

9 Shape staggering: Theory, MCSM protons neutrons Q, μ and δ<r 2 > values are reproduced by the theory change of spin-orbit splitting due to the n-p tensor forces

α-γ, γ -γ coincidence levels, E γ hindrance factors transition multipolarities

10 α- and β-decay studies with the laser ion source Main information: I, δ<r 2 >, μ, Q Windmill station Additional information: T 1/2 E α, b α, b β Q α (masses) α-γ, γ -γ coincidence levels, E γ hindrance factors transition multipolarities conversion coefficients E0 transitions partial decay schemes (isomer selectivity)

11 Large hindrance of α decay 180 Tl g 176 Au g R o 1/2 2μ 1/ 2 P= exp 2 ( V Qα ) dr h Ri b ln(2) h δ =, δ kev HF 1 2 α 2 α α T1/2 P B. Andel et al., Phys. Rev. C 96, (2017)

12 Large hindrance of α decay 180 Tl g 176 Au g 178 Tl 180 Tl 182 Tl E α (kev) δ 2 (kev) E α (kev) δ 2 (kev) E α (kev) δ 2 (kev) 6862(10) 0.30(15) 6553(7) 0.16(11) (25) 6693(10) 13.0(17) 6354(7) 2.9(19) 6360(6) 0.048(28) 6595(10) 10.2(24) 6348(7) 0.27(18) 6165(6) 1.13(66) Strongly hindered gs gs decay (δ 2 ~0.1keV; HF~500) at the same spin and deformation! Large hindrance is due to the change of both proton, s 1/2 d 3/2, and neutron, h 9/2 f 7/2, configurations (confirmed by our μ measurements). 176 Au 180 Tl Configuration I μ add (μ N ) μ exp (μ N ) πd 3/2 νf 7/ (9) πd 3/2 h 9/ (9) Configuration I μ add (μ N ) μ exp (μ N ) πs 1/2 νh 9/ (23) πs 1/2 νf 7/ (23) Why does neutron in 176 Au occupy f 7/2 instead of expected h 9/2 orbital?

Nuclear shells below N = 100 All N = 83 (85) nuclei are of νf 7/2 configuration: spin, parity, μ (from 54 Xe 83 to 70 Yb 83 ) N = 99: 181 Pb 99, 9/2, νh 9/2 100 179,177 Hg 99,97, 7/2 and μ

13 Nuclear shells below N = 100 All N = 83 (85) nuclei are of νf 7/2 configuration: spin, parity, μ (from 54 Xe 83 to 70 Yb 83 ) N = 99: 181 Pb 99, 9/2, νh 9/ ,177 Hg 99,97, 7/2 and μ coincides with μ(n = 83) Q corresponds to hole states in f 7/2 shell S. Sels et al., In-source laser resonance-ionization spectroscopy of neutron-decient Hg isotopes (accepted by Phys. Rev. C)

of nh 9/2 and nf 7/2 states due to the tensor forces 2f 7/2 1h 9/2 Z = 54,

14 Shell swap neutrons neutrons 3p 1/2 3p 1/2 2f 5/2 1i 13/2 protons neutrons 2f 5/2 1i 13/2 π=+ Sub shell 1h 9/2 2f 7/2 change in the relative position of nh 9/2 and nf 7/2 states due to the tensor forces 2f 7/2 1h 9/2 Z = 54, N = 83 Z = 80, N = 99 T Otsuka and Y Tsunoda J. Phys. G: 43 (2016)

15 Hindrance factors andμfor 1/2 + nuclei reduced width for 1/2 + 1/2 + α decay unhindered 1/2 + 1/2 + decay N g factors J. Cubiss et al., Phys. Lett. B 786 (2018) 355

16 Nonaxiality in 177, 179 Au 177, 179 Au, μ ~ 1n.m. 187, 189 Au, μ ~ 0.5n.m. Thus, the structures of 1/2 + states in parent 181 Tl and daughter 177 Au are different: spherical s 1/2 state in 181 Tl and nonaxially deformed mixture of s 1/2 and d 3/2 states in 177 Au hindrance of the α decay

17 Isomer-selective Indium photoionization Low-lying states in 133 Sn pure I = 1/2 isomer pure I = 9/2 isomer M. Piersa et al., Acta Phys. Polon., B49 (2018) 523; Phys. Rev. C (accepted)

18 New efficient ionization scheme for Ra T. Day Goodacre et al., Spectrochim. Acta, B150, 99 (2018); K. M. Lynch et al., Phys. Rev. C 97, (2018).

19 Laser ion source: summary Заключение (2018) 1. Измерены изотопические сдвиги и сверхтонкое расщепление (μ, Q, δ<r 2 >) для 15 изотопов (изомеров) 80 Hg на переходе nm. Продемонстрировано исчезновение эффекта shape staggering при А< Изомерно-селективная фотоионизация в лазерном ионном источнике позволяет получить большой объем ядерноспектроскопической информации (T 1/2, E α, b α, b β, α-γ, γ -γ coincidence, conversion coefficients, partial decay schemes ит. д.) без дополнительных затрат времени. Из полученных результатов отметим: 1. Большой фактор задержки α распада 180 Tl 176 Au, атакже анализ спинов и моментов соседних изотопов Hg указывает на изменение оболочечной структуры (shell swap). 2. Сопоставление фактора задержки α распада 181 Tl 177 Au со спинами и магнитными моментами этих ядер позволяет сделать вывод о неаксиальной деформации 177, 179 Au.

Resonant laser ionization of Po at ISOLDE

Resonant laser ionization of Po at ISOLDE IKS, KULeuven T.E. Cocolios, M. Huyse, Yu. Kudryavtsev, P. Van Duppen ISOLDE, CERN V.N. Fedosseev, K. Johnston, B.A. Marsh IPNO, Orsay S. Franchoo Johannes Gutenberg