Centre de Sciences Nucléaires et de Sciences de la Matière Precision mass measurements of neutron-rich chromium isotopes with ISOLTRAP Maxime Mougeot Centre de Sciences Nucléaires et de Sciences de la Matière CSNSM-Orsay ISOLDE Workshop-08/12/2016

Mass measurements of neutron-rich chromium isotopes Outline: Physics motivation Mass measurements of neutron-rich chromium isotopes Results and Discussion Conclusions and outlook

Physics Motivation

An onset of collectivity around N=40 neutrons 28 50 1f7/2 2p3/2 1f5/2 2p1/2 1g9/2 2d5/2 40 protons S. M. Lenzi et al., Phys. Rev. C 82, 054301 (2010). ENSDF database (2015). C. Santamaria et al.,PRL 115, 192501 (2015).

What does the mass surface look like? M. Wang et al., Chinese Physics C 36, 1603 (2012). S. Naimi et al., Phys. Rev. C 86, 014325(2012). F. Wienholtz et al., Nature 498, 346 (2013). X. Xing et al., Chinese Physics C 39, 104001 (2015). L.P Gaffney et al., Eur. Phys. J. A 51, 136 (2015).

What does the mass surface look like? M. Wang et al., Chinese Physics C 36, 1603 (2012). S. Naimi et al., Phys. Rev. C 86, 014325(2012). F. Wienholtz et al., Nature 498, 346 (2013). X. Xing et al., Chinese Physics C 39, 104001 (2015). Z. Meisel et al., Phys. Rev. C 93, 035805 (2015) L.P Gaffney et al., Eur. Phys. J. A 51, 136 (2015).

The IS532 experiment

ISOLTRAP@ISOLDE@CERN RILIS ISOLTRAP 1.4-GeV protons from PSB ISOL beams

Where is the Ion of Interest?

Multi-Reflection Time-Of-Flight Mass Separator F. Herfurth et al., NIM A 469, 254 (2001). R. N. Wolf et al., Int. J. Mass Spectrom 313, 8 (2012). G. Savard et al., Phys. Lett. A 158, 247 (1991). M. König et al., Int. J. Mass Spectrom. 142, 95 (1995).

The precision Penning Trap : the ToF-ICR technique F. Herfurth et al., NIM A 469, 254 (2001). R. N. Wolf et al., Int. J. Mass Spectrom 313, 8 (2012). G. Savard et al., Phys. Lett. A 158, 247 (1991). M. König et al., Int. J. Mass Spectrom. 142, 95 (1995).

IS532 measurements –First measurements in 2014 52,55-58Cr measured in the Penning Trap 59Cr measured with MR-TOF MS 59Cr provided a successful test of RILIS ionization scheme T.D Goodacre et al., Spectrochimica Acta B (in press)

Dedicated chromium beam time in 2016 isotope Measured with Half life (ms) Yield (ions/s) 59Cr Penning Trap/MR-TOF 1050 3E5 60Cr 490 2E4 61Cr 243 2E3 62Cr 206 3E2 63Cr MR-TOF 129 30 T.D Goodacre et al., Spectrochimica Acta B (in press)

Discussion

The mass surface Z. Meisel et al., Phys. Rev. C 93, 035805 (2015).

Preliminary The mass surface Z. Meisel et al., Phys. Rev. C 93, 035805 (2015).

Comparison to theoretical models neutrons 28 50 1f7/2 2p3/2 1f5/2 2p1/2 1g9/2 2d5/2 protons LNPS’ valence space 40 40 * *In Medium Similarity Renormalization Group (ab initio method) K. Sieja, private communication(2016). M. Honma et al, Eur. Phys. J. A 25, 499 (2005) Stroberg et al., PRL in press. Stroberg, Holt, Simonis, Schwenk, private communication(2016).

Comparison to theoretical models neutrons 28 50 1f7/2 2p3/2 1f5/2 2p1/2 1g9/2 2d5/2 protons GXPF1A and IMSRG valence space 40 40 * *In Medium Similarity Renormalization Group (ab initio method) K. Sieja, private communication(2016). M. Honma et al, Eur. Phys. J. A 25, 499 (2005) Stroberg et al., PRL in press. Stroberg, Holt, Simonis, Schwenk, private communication(2016).

Conclusions

Exotic chromium isotopes up to A=63 were measured To conclude : Exotic chromium isotopes up to A=63 were measured Data suggest a progressive onset of deformation Only interactions allowing excitations across N=40 can qualitatively reproduce the trend of experimental S2n

Other observables would help completing the picture Perspectives: Other observables would help completing the picture (e.g radii: H. Heylen et al., CERN-INTC-2016-057) The inclusion of shells beyond N=40 in the IMSRG framework is currently being developed H. Heylen et al., Phys. Rev. C 94, 054321 (2016).

Acknowledgements http://isoltrap.web.cern.ch D. Atanasov, K. Blaum, S. George, F. Herfurth, D. Lunney, V. Manea, D. Neidherr, M. Rosenbusch, L. Schweikhard, A. Welker, F. Wienholtz, R. Wolf, K. Zuber Grants No.: 05P12HGCI1 05P12HGFNE  ISOLDE Target and Technical Group http://isoltrap.web.cern.ch

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