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FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Nuclear structure probed by precision atomic mass measurements in a Penning trap Ari.

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Presentation on theme: "FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Nuclear structure probed by precision atomic mass measurements in a Penning trap Ari."— Presentation transcript:

1 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Nuclear structure probed by precision atomic mass measurements in a Penning trap Ari Jokinen Department of Physics University of Jyväskylä

2 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL (Short) introduction M(Z,N) = Mm n + Zm p + B(Z,N) contains all information of the structure of the nucleus Weak interaction studies and fundamental physics: (0+  0+, -physics, , part.-antipart., …) Sub-keV precision of less exotic nuclei: Data from dedicated experiments with stable isotopes and reaction Q-values Nuclear structure and nuclear astrophysics: Atomic masses of exotic isotopes with 1-100 keV precision: Usually based on the decay studies (Q , Q , …), extrapolations and interpolations (AME) and mass predictions

3 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Penning trap (and storage ring) era Access to Direct mass measurements of short-lived and rare isotopes with improved precision ! ATOMIC MASSES for nuclear physics: - benchmark mass predictions and nuclear structure theories - input for improved predictions far from stability BINDING ENERGIES and their DIFFERENCES over long chains of isotopes provide experimental information and verification: - evolution of nuclear structure - evolution shell gaps - pairing correlations - …

4 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL JYFLTRAP setup at IGISOL 1) K130 accelerator: I p ~ 50  A and E p ~ 20-70 MeV) HI-ions up to 132 Xe (~5 MeV/u) Plenty of on-line time (K130 beam-on-target 7000 h/year) 1 3) Spectroscopic information: Access to complementary information of nuclear structure vie decay spectroscopy and collinear laser spectroscopy 3 3 3 4) JYFLTRAP: Combination of RFQ cooler.buncher and Tandem Penning trap located in 7T superconducting solenoid: - M/  M purification 1-2 x 10 5 - Precision mass measurement applying TOF - Few keV precision for NS studies - 8 x 10 -9 precision for Q EC - 62 Ga, T 1/2 =116ms, +/- 540 eV, 1.8 x 10 -8 4 2) Ion Guide ISOL: LI-IG, HI-IG, fission IG Chemically inselective Fast (ms-regime) 1+ DC-beam at 30 keV with M/  M ~300 2 MASS MEASUREMENTS WITH JYFLTRAP

5 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Critical survey of AME and previous data; Nb U. Hager et al., NPA 793 ( 2007) 20 A. Kankainen et al., EPJA 29 (2006) 271

6 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL JYFLTRAP data vs. AME 2003 N-def. A~100 0+  0+ N-rich A~100

7 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Mass predictions vs. JYFLTRAP data U. Hager et al., NPA 793 ( 2007) 20 1. Tendency: Mass predictions and AME deviate from new precise data, but they often agree with each other !  Are predictions guided (too much) by AME ? 2. Plenty of new data and more is coming, but AME update will take years  model benchmarking and adjustment should be based on the experimental data !

8 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Binding energies in transitional region A~100 20406080 0 Quadrupole deformation  2 of even-even nuclei HFB + THO + LN M.V. Stoitsov et al., Phys. Rev. C 68 (2003) 054312  2 < -0.2 -0.2 - -0.1 -0.1 - +0.1 -0.1 - +0.2 +0.2 - +0.3 +0.3 - +0.4 > + 0.4 Shape changes Shell gaps and sub-shell closures

9 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Two-neutron separation energies from Ni to Pd

10 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Two-neutron separation energies from Tc to Pd

11 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Two-proton separation energies below 100 Sn New data removes some of irregularities in the existing old data compiled in AME !  Liquid-drop behaviour

12 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Discontinuity at N~60, Z~40

13 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL  2 =0.0  2 =0.3  2 =0.4 Observed discontinuity appears in expected region of rapid changes of deformation and agrees perfectly with the recent collinear laser spectroscopy data Discontinuity at N~60, Z~40 – shape effect

14 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL N=50 shell gap

15 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL N=50 shell gap extracted from AME2003 ?

16 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL N=50 shell gap from AME2003+Penning trap data

17 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL J.M. Pearson and S. Goriely, Nucl. Phys. A 777 (2006) 623-644 Z=28 Shell gap energies – predictions  2n (N o ) = S 2n (N o )-S 2n (N o +2)

18 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Pairing OES of nuclear binding energies  pairing-gap energy in the standard BCS theory Differences measured masses   n or  p G = strength of the pairing interaction  = single-particle energy = chemical potential Bohr-Mottelson  n = 12/A 1/2 [MeV], fixed Z Bohr-Mottelson  n = 12/A 1/2 [MeV], fixed A D.G. Madland and J.R. Nix, NPA476 (1988) 1  n = 5.7 exp(0.12I-8I 2 )/N 1/3 [MeV] P. Vogel, B. Jonson and P.G. Hansen, PL 139B (1984) 227  n = (7.4-45I 2 )/A 1/3 [MeV]  n = ¼(-1) A-Z+1 [S n (A+1,Z)-2S n (A,Z)+S n (A-1,Z)]c 2  = ¼(-1) A-Z+1 [-M(A+1,Z)+3M(A,Z)-3M(A-1,Z)+M(A-2,Z)]c 2

19 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Pairing energies; close look as f(N)  n = ¼(-1) A-Z+1 [S n (A+1,Z)-2S n (A,Z)+S n (A-1,Z)]c 2  = ¼(-1) A-Z+1 [-M(A+1,Z)+3M(A,Z)-3M(A-1,Z)+M(A-2,Z)]c 2 Connection to:  in BCS-theory ? Pairing functional ???

20 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Proton-neutron pairing energies for o-o N=Z nuclei LEBIT, MSU (G. Bollen): Precise mass measurements of short-lived Ge, As and Se isotopes close to N=Z=33. Vanishing of Wigner energy while approaching 100 Sn ? P. Schury et al., PRC75 (2007) 055801 Indication of re-strengthening of V np – to be verified by further mass measurements !

21 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Summary and outlook ISOLTRAP, JYFLTRAP, LEBIT, SHIPTRAP, CPT and TITAN: 600 isotopes with keV-range precision and more to come … ESR for the shortest half-lives and the most exotic cases with limited accuracy

22 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL Precise direct masses of exotic isotopes: Deficiencies in existing data set far from stability  Faults in AME compilation Misguidance of atomic mass predictions and other models trying to reproduce AME mass surface Differences of atomic masses with keV-range accuracy: Variations in two-particle separation energies reflects underlying nuclear structure Evolution of shell gaps Pairing gaps Proton-neutron pairing energies …

23 FIDIPRO-JSPS Workshop, Keurusselkä 25-27.10.2007, AriJokinen, JYFL V.-V. Elomaa T. Eronen U. Hager J. Hakala A. Jokinen A. Kankainen P. Karvonen T. Kessler I. Moore H. Penttilä S. Rahaman S. Rinta-Antila J. Rissanen J. Ronkainen A. Saastamoinen T. Sonoda C. Weber J. Äystö Department of Physics, P.O.Box 35 (YFL) FIN-40014 University of Jyväskylä Acknowledgements:


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