Xi aofei Yang @ IKS KU LEUVEN

1. Laser spectroscopy on Zn isotopes and isomers Spin, moments, charge radii Xiaofei Yang @ IKS KU LEUVEN Dec 2-4 ISOLDE workshop @CERN • Motivation • Collinear laser spectroscopy • Spins, moments and charge radii • Summary

2. Motivations Experiments Results & discussion Summary 3s1/2 Zn 1g7/2 2d5/2 50 1g9/2 40 2p1/2 1f5/2 2p3/2 28 28 1f7/2 78Ni 78Ni Neutron Proton 30 Investigate the nuclear structure in Zn30 isotopic chain (near closed shell Z=28,N=40,50) by measurement of spins, moments and charge radii 50 40 1

3. Motivations Experiments Results & discussion Summary Laser Spectroscopy Method Hyperfine structure (HFS)-> link between atomic parameters and nucleus parameters △E= A・K/2 +B・{3K(K+1)/4 –I(I+1)J(J+1)}/{2(2I-1)(2J-1)IJ} 3S1 -2.5A+1.25B -A+B // Atomic parameters 1/2 • Magnetic dipole HF parameter 3/2 3P1 1.5A+0.25B 5/2 ν 1/2 • Electric quadrupole HF parameter 3/2 5/2 7/2 I = 3/2 • Centroid ν0 Isotopes shift HFS • the nuclear spin I • the magnetic dipole moment m • the electric quadrupole moment Q • nuclear charge radius <r2> Nucleus parameters 2

4. Motivations Experiments Results & discussion Summary Collinear Laser Spectroscopy@ ISOLDE - CERN Ti: Sa Doubler 481.1873 nm Post-acceleration voltage PMTs Electrostatic deflectors Gated signal for PMTs Reducing the background photon counts Ion beam from HRS Mirror Counts from PMTs 3S1 RFQ buncher CEC Laser-excitation PMT detection 3P2 Laserfrequency Calvin Wraith et al., in preparation (2015) 3

5. Motivations Experiments Results & discussion Summary Assignment of the nuclear spins for isomers and ground states Aup Adown • Ratio Aup/Adown:constant • （hyperfine anomaly is negligible） • A(S1) / A(P2) =2.383(2) • depends on nuclear spin assumed • in fitting procedure New confirmed spins 3S1 481.1873 nm 3P2 1S0 Calvin Wraith et al., in preparation (2015) 4

6. Motivations Experiments Results & discussion Summary • g-factors-> deduced from the determined magnetic moment Information on the orbit occupied by unpaired neutron(s): compare data to effective single particle g-factors (0.7 gsfree) • The 3/2- gs (63Zn) with mixed configuration • The 5/2- gs (63,65Zn) have unpaired particles • in f5/2 orbit • The 1/2- gs/isomer from a single neutron in • in p1/2 orbit 7/2+ 9/2+ 7/2+ 9/2+ • Positive parity for the gs/isomer in 69-79Zn • has unpaired particles/holes in ng9/2 • -> 5/2+ isomer in 73Zn has some mixing ! 9/2+ 5/2+ • Confirm the positive parity of the ½ isomer • in 79Zn confirmed • -> only ns1/2 has strong negative g-factor • -> some mixing with nd5/2 configuration f5/2 p1/2 g9/2 Effective single-particle g factor Calvin Wraith et al., in preparation (2015) 5

7. Motivations Experiments Results & discussion Summary g-factors: states with dominant n(g9/2)n configuration JUN45/jj44b interaction P: 30 N: 33-39 Model Space 50 1g9/2 1f5/2 2p3/2 2p1/2 28 28 1f7/2 56 Ni core JUN45: M. Honma et al., Phys. Rev. C 80, 064323 (2009). jj44b: D. Verney et al., Phys. Rev. C 76, 054312 (2007).  the 5/2- state in 73Zn has more mixing !  this is reproduced by the JUN45 interaction Calvin Wraith et al., in preparation (2015) 6

8. Occupation numbers of proton/neutron from JUN45 calculation Motivations Experiments Results & discussion Summary Proton/neutron occupation numbers in the positive parity high-spin levels calculated by JUN45 • As neutrons are added to the g9/2, the occupation number in πf5/2 increase but decrease in πp3/2. • An inversion of occupation occurs in πp3/2 / πf5/2 around 76Zn46(Z=30), which is consistent with the inversion of the proton orbit due to tensor effect. It is known to occur in 75Cu46 (Z = 29) and 79Ga48 (Z = 31). • A kink appear around 73Zn, suggesting • anincrease of configuration mixing for • the 5/2+ isomer in 73Zn P-h excitations across N=40 in 69-77Zn Calvin Wraith et al., in preparation (2015) 7

9. Motivations Experiments Results & discussion Summary Large deformed isomer RMS Charge radii N=40 N=28 N=50 M. L. Bissell et al., “to be submitted,” (2015) T. J. Procter et al., Phys. Rev. C 86, 034329 (2012). N. Wang and T. Li, Phys. Rev. C 88, 011301 (2013). I. Angelia and K. Marinova, At. Data Nucl. Data Tables99, 69 (2013). • a weak N=40 sub-shell effect • a clearly N=50 shell effect Liang Xie et al., in preparation (2015) 9

10. Motivations Experiments Results & discussion Summary Data are taken from NNDC Xiaofei Yang et al., in preparation (2015) 10

11. Motivations Experiments Results & discussion Summary Summary ~200 ms Spins and moments are known Nuclear moments are confirmed in this work Spins and moments are confirmed in this work S.V. Ilyushkin et al., PRC 83, 014322 (2011); R.Orlandi et al., PLB740, 298(2015) M. Huhta et al., PRC 58,3187(1998); S.V. Ilyushkin et al., PRC 80, 054304 (2009); 11

12. Thanks for your attention! 12

13. Motivations Experiments Results & discussion Summary Quadrupole moment -> (Agree with the shell model calculation with jj44b/JUN45) 7/2+ 5/2+ 3/2- 7/2+ p1/2 f5/2 g9/2 N.S. Laulainen et al.,Phys. Rev. 177,1606(1969) F.W. Byron et al.,Phys. Rev. 134, A47(1964) F.W. Byron et al.,Phys. Rev. 134, A47(1964) D. Oertel et al., Z. Phys. A 310, 233-241 (1983) Calvin Wraith et al., in preparation (2015) 8

19. Weisskopf estimate

22. SF 0.41(10) 746ms SF 0.38(5)