1. Collinear Laser Spectroscopy of Neutron Rich Potassium, Calcium and Manganese Isotopes M. L. Bissell on behalf of the COLLAPS collaboraion

2. COLLINEAR LASER SPECTROSCOPY 2 ISOTOPE SHIFTS The difference in optical transition frequency between 2 isotopes( ν A - ν A’ ) Atomic Factors Difference in mean square charge radius of 2 isotopes ( δ‹r 2 › A,A’ ) HYPERFINE STRUCTURE Splitting of an optical line via EM interactions between the electron and nucleus More Atomic Factors Nuclear Spin, magnetic moment and electric quadrupole moment

3. COLLINEAR LASER SPECTROSCOPY 3 COLLAPS set-up 1.) ion beam; 2.) laser; 3.) deflection plates; 4.) post acceleration 5.) charge exchange; 6.) optical detection; Imaging

4. BUNCHED BEAM - COLLINEAR LASER SPECTROSCOPY How does it work? Major background in collinear laser spectroscopy : -PMT dark counts + scattered laser light. Limits sensitivity to ≈ few x 10 5 ions/s. -Bunching the ion beam means we only count when the ions are in front of the PMT’s. -100 ms accumulation in ISCOOL + 3μs bunch width gives ≈ 3x10 4 background suppression. Now sensitive to a few 100 ions/s. 4 T ac ≈ 100 ms T b ≈3μs accumulation release 52 Ca with ≈ 300 ions/s after 4 hours April 2012 Similar benefits for many recent COLLAPS runs: Ga, Cu, K, Cd, Mn…

5. MOTIVATIONS 5 N=20 N=28 40 Ca 35 P 41 Ca 39 Ar 38 Cl 37 S 36 P 39 Cl 38 S 37 P 42 K 41 Ar 40 Cl 39 S 38 P 43 K 42 Ar 41 Cl 40 S 39 P 45 Ca 44 K 43 Ar 42 Cl 41 S 40 P 45 K 44 Ar 43 Cl 42 S 41 P 47 Ca 46 K 45 Ar 44 Cl 43 S 42 P 47 K 46 Ar 45 Cl 44 S 43 P 39 Ca 38 K 37 Ar 36 Cl 35 S 34 P 42 Ca 43 Ca 44 Ca 46 Ca 48 Ca 39 K 40 K 41 K 40 Ar 38 Ar 37 Cl 36 S  d 3/2  s 1/2 Z=17 Z=20 f 7/2 p 3/2 Z=19 48 K 49 K 50 K 51 K (1/2,3/2)? ???????? What happens with the filling of the p 3/2 ?

6. MOTIVATIONS 6 β-decay spectroscopy, deep inelastic scattering and Coulomb- excitation experiments have all provided evidence for a sub-shell closure at N=32. BUT no direct experimental evidence exists for such a closure at N=34. A.Gade, T. Glasmacher, Progress in Particle and Nuclear Physics 60, 161–224 (2008) 54 Ca is “the key nucleus for a search for the new magic number N=34.”

7. SPINS & MOMENTS - POTASSIUM 7 J. Papuga et al., PRL 110,172503 (2013) K. Kreim et al., In preparation

8. SPINS & MOMENTS - POTASSIUM 8 PROTONS IN 48 K not inverted??

9. CHARGE RADII- POTASSIUM 9 πd 3/2 ? πs 1/2

10. Quadrupole Moments - Ca 10 Original work did not give a Q for this due to unreliability of B factors.

11. SPINS & MOMENTS - MANGANESE 11 J=5/2 - 3/2 transition with high spins and isomers = Difficult

12. SPINS & MOMENTS - MANGANESE 12 MnLiterature spin assignment Very Preliminary Very Preliminary Spin determinations 57 5/2 58g 1 1 58 m (4) 4 59 (5/2) 5/2 60g 0 1 60 m 3 4 61 (5/2) 5/2 62g 1 1 62 m (4) 4 63 - 5/2 64 (1) 1 Based on a number of factors- 1) Number of components 2) Relative intensities 3) Feasibility of quadrupole moment …. Final analysis ongoing.

13. Charge Radii 13 N = 32,34 ?? F. Wienholtz et al., Nature, 498, 346 (2013)

14. Charge Radii 14 Why do we see a signature for N=32 in the masses but not in the charge radii? 1) Consider the normal odd-even staggering in binding energies… A)Even N more bound than odd N due to pairing energy + the repulsive effect of off diagonal mixing. B)Shell closures correspond to more binding. → Masses tell us about the size of the shell gap. 2) Consider the normal odd-even staggering in charge radii… A)Even N larger than odd N due to mixing with orbitals of larger spatial extent. B)Shell closures make smaller size size due to reduction of mixing. → Charge radii tell us about the mixing across the shell gap.

15. Charge Radii – Theoretical descriptions 15 E. Caurier et al., Phys. Lett., B, 522, 240 (2001) Stéphane Goriely, private communication. After N=28 ?? If Ca radii followed Mn then we soon arrive at a completely inverted proton distribution! (~7 protons in pf by N=40.) Before N=28 ?? Trend ok but missing the detail related to the interplay between proton and neutron correlations.

16. Outlook for Ca 16 Radioactive detection of Optically pumped ions after state selective Charge exchange (ROC) The theoretical possibilities: 1 ion/s of an even isotope over 5 shifts.

17. Outlook for Ca Radioactive detection of Optically pumped ions after state selective Charge exchange (ROC)

18. Thanks To 18 Carla Babcock 4, Ivan Budincevic 2, Klaus Blaum 3, Bradley Cheal 4, Marieke de Rydt 2, Nadja Frömmgen 5, Ronald Garcia Ruiz 2, Christopher Geppert 7,8, Michael Hammen 5, Hanne Heylen 2, Magdalena Kowalska 9, Kim Kreim 3, Andreas Krieger 5,8, Rainer Neugart 3, Gerda Neyens 2, Wilfried Nörtershäuser 8,10,5, Jasna Papuga 2, Mustafa Rajabali 2, Rodolfo Sanchez-Alarcon 7,10, Stefan Schmidt 5,8,10 and Deyan Yordanov 3 — 2 Instituut voor Kern- en Stralingsfysica, Katholieke Universiteit Leuven, Belgium — 3 Max-Planck-Institut für Kernphysik,Heidelberg, Deutschland — 4 School of Physics and Astronomy, University of Manchester, M13 9PL, UK — 5 Institut für Kernchemie, Johannes Gutenberg-Universität Mainz, Deutschland — 7 Helmholtz-Institut Mainz, Mainz, Deutschland — 8 Institut für Kernphysik, Technische Universität Darmstadt, Darmstadt, Deutschland — 9 CERN,Physics Department, Geneva, Switzerland — 10 GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Deutschland