2-7 June 2019
Simon Fraser University
America/Vancouver timezone
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Structure of $^{188}$Hg From Gamma-ray Spectroscopy With GRIFFIN

5 Jun 2019, 10:45
15m
DAC FT I (Simon Fraser University)

DAC FT I

Simon Fraser University

Oral Competition (Graduate Student) / Compétition orale (Étudiant(e) du 2e ou 3e cycle) Nuclear Physics / Physique nucléaire (DNP-DPN) W1-10 Nuclear Structure III (DNP) | Structure nucléaire III (DPN)

Speaker

Mr Andrew MacLean (University of Guelph)

Description

Neutron deficient nuclei near Z=82 exhibit one of the most extensive manifestations of shape coexistence across nuclear chart [1]. In the even-even mercury isotopes, $^{182-188}$Hg, Coulomb excitation experiments have provided a sensitive probe to determine the E2 matrix elements, giving information on the nature of the deformation for nuclear states [2]. Precise measurements of absolute and relative B(E2) values for transitions between the shape-coexisting states also provide important information on their mixing [2,3].

For $\Delta J\neq 2$ transitions between states of the same parity, the determination of $B(E2;J_i\rightarrow J_f)$ values depends on the $E2/M1$ mixing ratios, $\delta$. Precise measurements of these mixing ratios, however, are often challenging. One of the best methods to extract the mixing ratios is through $\gamma-\gamma$ angular correlation measurements following $EC/\beta$ decay where a very high sensitivity can be achieved. We have recently adopted this technique for the GRIFFIN $\gamma$-ray spectrometer, located at the ISAC facility at TRIUMF, and have applied it to measurements of the $EC/\beta$ decay of $^{188-200m}$Tl to $^{188-200}$Hg. Also Included in this measurement was the PACES array, used for the detection of conversion electrons to determine E0 transition strengths.

Our first results, for $^{188}$Hg indicate the dominance of the $E2$ components in
the $J\rightarrow J$ transitions. In addition to enabling the determination of the $B(E2)$ values, knowledge of these mixing ratios are also critical for the extraction of $E0$ components which may be enhanced if there are significant mixings between the shape-coexisting configurations. Results on angular correlation measurements and $E0$ transition strengths for $^{188}$Hg will be presented.

[1] K. Heyde, J. L. Wood, Rev. Mod. Phys. 83, 1467(2011).
[2] N. Bree et al. Phys. Rev. L 112, 162701(2014).
[3] L. Gaffney et al., Phys. Rev. C 89, 024307 (2014).

Primary author

Mr Andrew MacLean (University of Guelph)

Co-authors

Dr F. A. Ali (Department of Physics, University of Guelph, Guelph, ON, and Department of Physics, University of Sulaimani, Kurdistan Region, Iraq) Dr C. Andreoiu (Department of Chemistry, Simon Fraser University, Burnaby, BC) Dr G. C. Ball (Physical Sciences Division, TRIUMF, Vancouver, BC) Ms N. Bernier (Physical Sciences Division, TRIUMF, Vancouver, BC and Department of Physics, University of British Columbia, Vancouver, BC) Mr H. Bidaman (Department of Physics, University of Guelph, Guelph, ON) Dr V. Bildstein (Department of Physics, University of Guelph, Guelph, ON) Dr M. Bowry (Physical Sciences Division, TRIUMF, Vancouver, BC) Dr R. Caballero-Folch (Physical Sciences Division, TRIUMF, Vancouver, BC) Ms A. Varela Diaz (Department of Physics, University of Guelph, Guelph, ON) Dr I. Dillmann (Physical Sciences Division, TRIUMF, Vancouver, BC and Department of Physics, University of Victoria, Victoria, BC) Dr M. R. Dunlop (Department of Physics, University of Guelph, Guelph, ON) Mr R. Dunlop (Department of Physics, University of Guelph, Guelph, ON) Dr A. B. Garnsworthy (Physical Sciences Division, TRIUMF, Vancouver, BC) Dr P. E. Garrett (Department of Physics, University of Guelph, Guelph, ON) Dr G. Hackman (Physical Sciences Division, TRIUMF, Vancouver, BC) Mr B. Jigmeddorj (Department of Physics, University of Guelph, Guelph, ON) Dr A. I. Kilic (Department of Physics, University of Guelph, Guelph, ON) Dr A. T. Laffoley (Department of Physics, University of Guelph, Guelph, ON) Ms H. P. Patel (Physical Sciences Division, TRIUMF, Vancouver, BC) Dr B. Olaizola (Physical Sciences Division, TRIUMF, Vancouver, BC,) Mr Y. Saito (Physical Sciences Division, TRIUMF, Vancouver, BC and Department of Physics, University of British Columbia, Vancouver, BC) Dr J. Smallcombe (Physical Sciences Division, TRIUMF, Vancouver, BC) Dr J. K. Smith (Department of Physics, Reed College, Portland, Oregon) Dr C. E. Svensson (Department of Physics, University of Guelph, Guelph, ON) Mr J. Turko (Department of Physics, University of Guelph, Guelph, ON) Mr K. Whitmore (Department of Chemistry, Simon Fraser University, Burnaby, BC) Mrs T. Zidar (Department of Physics, University of Guelph, Guelph, ON)

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