Lifetime Measurements in Lifetime Measurements in N=ZN=Z 7272KrKrLifetime Measurements in Lifetime Measurements in N=ZN=Z 7272KrKr

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

OutlineOutline

Motivation

Experimental set-up

Results & Discussions

Conclusions

Delayed Alignments?Delayed Alignments?

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)

24

400(150) fsQt = 2.52(47) eb

β = 0.37

61(16) fsQt = 1.15(15) eb

π(g9/2)2 x ν(g9/2)2

14(5) fs

1

Band 2-4: Δτ = 50 fs

4

Alignments in Alignments in 72,74,7672,74,76KrKr

ħω (MeV)

i x(ħ

)

Theoretical StudiesTheoretical StudiesKinetic Moments of InertiaKinetic Moments of Inertia

CRHB + LN, Gogny D1S (T = 1) Pairing

A.V. Afanasjev, S. Frauendorf, Phys. Rev. C, (2005) in press

pairingno pairing

Neutron Single Particle LevelsNeutron Single Particle Levels

Labelled: number of protons in g9/2 orbitalnumber of neutrons in g9/2 orbital

[p,n]

β2/β4

e ν (M

eV)

W. Nazarewicz et al. Nucl. Phys. A345, 397(1985)

ConfigurationsConfigurations

A.V. Afanasjev, S. Frauendorf, Phys. Rev. C, (2005) in press

band 2band 4

Transitional Quadrupole Moment and DeformationTransitional Quadrupole Moment and Deformation

A.V. Afanasjev, S. Frauendorf, Phys. Rev. C, (2005) in press

[2,2]

[3,3]b[3,3]a

CRHB + LN

CRMF

Z=Z=36 Kr Nuclei36 Kr Nuclei

N

N=ZZ

36

72 74 7573 76

37

Se

38 39 40

36

37

35

3470 71 72

73

73 74

74 757271

777675

7776 78

78 79

80

74

70

6968

3534

Kr

Br

Zr

38

39

40

Y

Sr

Ru

2

CN

Argonne National Laboratory, Chicago, USA

40Ca + 40Ca → 80Zr → 72Kr + 2α

Beam: 40Ca @ 164 MeV

Target: 350 μg/cm2 40Ca 150 μg/cm2 197Au

MicroballMicroball

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)

GammasphereGammasphere

• 110 HP Ge detectors, Compton Suppressed, 17 rings

• gamma ray multiplicity

• sum energy measurements

• total energy conservation selection

Gammasphere detector angles + kinematics of reaction (Microball)

Doppler correction of γ rays

MICROBALL

40Ca

I.Y. Lee, Nucl. Phys. A520, 641c, (1991)

High Spin States in High Spin States in 7272KrKr 30+

28+ Jtop + 4

24

Side Band

2α TEP - Band

ConfigurationsConfigurations

A.V. Afanasjev, S. Frauendorf, Phys. Rev. C, (2005) in press

band 2band 4

Low-Spin (Preliminary)Low-Spin (Preliminary)

Recoil out of target

Low spin

Band 2

Band 2 – High SpinBand 2 – High Spin

Band 4Band 4

Experiment & TheoryExperiment & Theory

[2,2]

[3,3]b[3,3]a

CRHB + LN

CRMF

ConclusionsConclusions

Extended the level scheme of N=Z 72Kr up to 30ħ Lifetime measurements at high spins in 72Kr using the DSAM Good agreement with theory with only T=1 (Gogny DS1) pairing

Future WorkFuture Work

Measure lifetimes of lower spin states using backed target data

AcknowledgmentsAcknowledgments

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

Argonne

National Laboratory

M.P. Carpenter

S.J. Freeman

F. Moore

D. Seweryniak

NSCU

D. Dashdorj

CEA Saclay

A. Goergen

York University

D. Jenkins

F. Johnston-Theasby

P. Joshi

R. Wadsworth

Washington University

W. Reviol

D.G. Sarantites

Lawrence Berkeley National Laboratory

A.O. Macchiavelli

D.D. Ward

TRIUMF

M.B. Smith

Tack sTack så mycket!å mycket!

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

Lund UniversityLund University

Side BandSide Band

Recoil out of target