Lifetime Measurements in N=Z 72Kr

1
Lifetime Measurements in NZ 72Kr
Corina Andreoiu

• International Conference on Finite Fermionic
  Systems ? Nilsson Model 50 YearsJune 14-18,
  2005, Lund, Sweden

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Outline

• Motivation
• Experimental set-up
• Results Discussions
• Conclusions

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4
Delayed Alignments?
2
p(g9/2)2 x ?(g9/2)2
Band 2-4 ?t 50 fs
14(5) fs
61(16) fs Qt 1.15(15) eb
4
1
400(150) fs Qt 2.52(47) eb ß 0.37
G. de Angelis et al. Phys. Rev. Lett. B 415, 217
(1997) S. Fischer et al. Phys. Rev. Lett. 87,
132501 (2001) N. Kelsall et al. Phys. Rev. C 64,
024309 (2001)
4
Alignments in 72,74,76Kr
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Theoretical StudiesKinetic Moments of Inertia
CRHB LN, Gogny D1S (T 1) Pairing
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Neutron Single Particle Levels
W. Nazarewicz et al. Nucl. Phys. A345, 397(1985)
7
Configurations
A.V. Afanasjev, S. Frauendorf, Phys. Rev. C,
(2005) in press
8
Transitional Quadrupole Moment and Deformation
CRHB LN
CRMF
A.V. Afanasjev, S. Frauendorf, Phys. Rev. C,
(2005) in press
9
Z36 Kr Nuclei

Z
NZ
Argonne National Laboratory, Chicago, USA 40Ca
40Ca ? 80Zr ? 72Kr 2a Beam 40Ca _at_ 164
MeV Target 350 µg/cm2 40Ca 150
µg/cm2 197Au
80
Zr
40
CN
78
79
39
Y
77
76
78
38
Sr
77
76
75
74
Ru
37
74
75
76
72
73
36
Kr
2a
73
74
75
72
71
70
35
Br
70
71
72
73
74
69
68
Se
34
36
39
40
37
38
35
34
N
10
Microball
95 CsI(Tl) scintilators 9 rings

• Identification of charged particles ? Channel
  selection
• Energy, momentum and angle of the charged
  particles ? Event by event kinematic
  reconstruction

D.G. Sarantites et al. NIM A381,418 (1996)
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Gammasphere

• 110 HP Ge detectors,
  Compton Suppressed, 17 rings
• gamma ray multiplicity
• sum energy measurements
• total energy conservation selection

40Ca
Gammasphere detector angles kinematics of
reaction (Microball) ? Doppler correction of ?
rays
MICROBALL
I.Y. Lee, Nucl. Phys. A520, 641c, (1991)
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2
High Spin States in 72Kr
30
4
Jtop 4
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2a TEP - Band
Side Band
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Configurations
A.V. Afanasjev, S. Frauendorf, Phys. Rev. C,
(2005) in press
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Low-Spin (Preliminary)
Band 2
Low spin
Recoil out of target
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Band 2 High Spin
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Band 4
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Experiment Theory
CRHB LN
CRMF
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Conclusions

• Extended the level scheme of NZ 72Kr up to 30h
• Lifetime measurements at high spins in 72Kr using
  the DSAM
• Good agreement with theory with only T1 (Gogny
  DS1) pairing

Future Work

• Measure lifetimes of lower spin states using
  backed target data

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Acknowledgments
University of Guelph P. Finlay P.E. Garrett G.F.
Grinyer B. Hyland A.A. Phillips M.A.
Schumaker C.E. Svensson J.J. Valiente-Dobon
McMaster University R.A.E Austin
NSCU D. Dashdorj
TRIUMF M.B. Smith
CEA Saclay A. Goergen
York University D. Jenkins F. Johnston-Theasby P.
Joshi R. Wadsworth
Argonne National Laboratory M.P. Carpenter S.J.
Freeman F. Moore D. Seweryniak
Washington University W. Reviol D.G. Sarantites
Lawrence Berkeley National Laboratory A.O.
Macchiavelli D.D. Ward
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Tack så mycket!
Lund University

• The Swedish Foundation for International
  Cooperation in Research and Higher Education

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Side Band
Recoil out of target