investigating shape coexistence with coulomb excitation above and below z=82 nele kesteloot 1,2 on...
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Investigating Shape Coexistence With Coulomb Excitation Above And Below Z=82
Nele Kesteloot1,2
On behalf of the IS452/IS479 collaboration
1KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven, B-3001, Belgium2SCK CEN (Studiecentrum voor Kernenergie, Mol, B-2400, Belgium
Shape coexistence• Different types of deformation at low excitation energy
• Interplay between two opposing tendencieso Stabilizing effect of closed shellso Residual proton-neutron interactionHeyde and Wood, Review of Modern Physics (2011)
Andreyev et al Nature 405:430 (2000)
• Evidence across the light lead region
• Lack of experimental informationo Nature of deformationo Degree of mixing
Shape coexistence Miniball @ REX-ISOLDE OutlookZ = 84:196-202Po Z = 80: 182-188Hg
2nd of June 2014 2ARIS 2014, Tokyo
T.E. Cocolios et al, Phys. Rev. Lett. (2011)
Miniball @ REX-ISOLDE
θP
2.9 MeV/A Projectile eg: 200Po
Target eg: 104Pd
EP
ET
2nd of June 2014 3ARIS 2014, Tokyo
Z = 82
Shape coexistence Miniball @ REX-ISOLDE OutlookZ = 84:196-202Po Z = 80: 182-188Hg
I182Hg = 4x10³ pps
I196Po = 2x104 ppsPurity = 54(1)%
I188Hg = 2x105 pps
I202Po = 7x104 ppsPurity = 98(2)%
Z = 84: 196-202Po: Quality of the data
ARIS 2014, Tokyo 4
• Data analysiso pγ coincidenceso Population of 2+
1 state in all isotopes
o Multi-step coulex observed in 196,198Po
• Extraction of matrix elementso Gosia o χ² fit of experimental data
196Po on 104Pd
Shape coexistence Miniball @ REX-ISOLDE OutlookZ = 84:196-202Po Z = 80: 182-188Hg
T. Czosnyka et al, Am. Phys. Soc. (1982)
2nd of June 2014 4ARIS 2014, Tokyo
196Po196Tl104Pd
Comparison with Beyond Mean Field
2nd of June 2014 5ARIS 2014, Tokyo
Lifetime experiments194Po: T. Grahn et al PRL 97, 062501 (2006)
196Po: T. Grahn et al PRC 80, 014323 (2009)
Shape coexistence Miniball @ REX-ISOLDE OutlookZ = 84:196-202Po Z = 80: 182-188Hg
J.M. Yao, M. Bender, P.-H. Heenen PRC 87, 034322 (2013)
Comparison with Beyond Mean Field:198Po
2nd of June 2014 6ARIS 2014, Tokyo
Experiment BMF
39(9)
180(50)
1.8(6)
300(300)
230(130)70(90)
25
90 53
1
37
63B(E2) down [Wu]
Shape coexistence Miniball @ REX-ISOLDE OutlookZ = 84:196-202Po Z = 80: 182-188Hg
J.M. Yao, M. Bender, P.-H. Heenen PRC 87, 034322 (2013)
Z = 80: 182-188Hg
0
N.Bree et al, PRL 112, 162701 (2014)
2nd of June 2014 7ARIS 2014, Tokyo
Shape coexistence Miniball @ REX-ISOLDE OutlookZ = 84:196-202Po Z = 80: 182-188Hg
Interpretation with two-level mixing modelα0+
2 α2+2 α4+
2
182Hg 92% 29% 3%184Hg 95% 51% 4%186Hg 98% 90% 7%188Hg 99% 98% 20%
“concealed” configuration mixing of the 2+
1 states of 182-188Hg
un-mixed ME2’s:
1.2 eb
3.3 eb 1.8 eb
-4.0 eb
0+I
2+I
0+II
2+II
182Hg184Hg186Hg188Hg
2nd of June 2014 8ARIS 2014, Tokyo
Shape coexistence Miniball @ REX-ISOLDE OutlookZ = 84:196-202Po Z = 80: 182-188Hg
N.Bree et al, PRL 112, 162701 (2014)
L.P. Gaffney et al, PRC 89, 024307 (2014)
Comparison to theory – IBM and BMF
2nd of June 2014 9ARIS 2014, Tokyo
Shape coexistence Miniball @ REX-ISOLDE OutlookZ = 84:196-202Po Z = 80: 182-188Hg
BMF: J.M. Yao, M. Bender, P.-H. Heenen PRC 87, 034322 (2013)IBM: J.E. Garcia-Ramos, K. Heyde PRC 89, 014306 (2014)
unmixed 2+1
unmixed 2+2
Courtesy of K. Wrzosek-Lipska
Outlook• Coulex of Po isotopes
o Finish analysiso Compare matrix elements with BMF and IBM
• HIE-ISOLDEo Radioactive ion beams @ 5MeV/A
• Continuation of shape-coexistence studies in the light lead region• Coulex of 182,184Hg: proposal accepted
• Establish deformation of 0+2 state
• B(E2)’s between non-yrast states up to 8+
o Extend studies towards odd-A
• SPEDE (Spectrometer for Electron Detection)o Detection of conversion electronso Constructed jointly by universities of Jyväskylä and Liverpool
2nd of June 2014 10ARIS 2014, Tokyo
Shape coexistence Miniball @ REX-ISOLDE OutlookZ = 84:196-202Po Z = 80: 182-188Hg
Thank you for your attention!
B. BastinE. ClémentN. Lecesne
N. BreeH. De WitteJ. DirikenL.P. GaffneyM. HuyseN. KestelootO. IvanovR. OrlandiN. PatronisI. StefanescuP. Van DuppenK. Wrzosek-Lipska
J. CederkällV. FedosseevL.M. FraileB. MarshE. PiselliE. RapisardaM. SeliverstovT. StoraD. VoulotJ. Van de WalleF. Wenander
T. GrahnR. JulinJ. KonkiJ. PakarinenP.J. PeuraP. Rahkila
A. BlazhevB. BruyneelCh. FransenK. GeibelH. HessP. ReiterB. SiebeckN. WarrA. Wiens
P.-H. Heenen, Université Libre de BruxellesK. Heyde, Ghent UniversityJ.L. Wood, Georgia Institute of TechnologyT. Kröll, Technische Universität DarmstadtM. Zielinska, CEA SaclayM. Bender, Université BordeauxM. Carpenter, Argonne National LaboratoryA. Ekström, University of LundJ.E. Garcia-Ramos, Universidad de Huelva
A. PettsP.A. ButlerR.-D. HerzbergR.D. Page
A. AndreyevJ. ButterworthD.G. JenkinsP. Marley
T.E. CocoliosA. DeaconC. FitzpatrickS.J. FreemanA.P. Robinson
B. HadiniaM. ScheckJ.F. Smith
K. Hadynska-KlekP.J. NapiorkowskiJ. Srebrny
R. GernhäuserR. Krücken
M. GuttormsenA.C. LarsenS. SiemG.M. Tveten
2nd of June 2014 11ARIS 2014, Tokyo