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
Outline:
Physics motivation
Mass measurements of neutron-rich chromium isotopes
Results and Discussion
 Conclusions and outlook
2
Physics Motivation
3
An onset of collectivity around N=40
2d5/2
2d5/2
50
40
50
1g9/2
1f5/2
40
1f5/2
2p1/2
2p1/2
2p3/2
2p3/2
28
28
1f7/2
neutrons
S. M. Lenzi et al., Phys. Rev. C 82, 054301 (2010).
ENSDF database (2015).
C. Santamaria et al.,PRL 115, 192501 (2015).
1g9/2
1f7/2
protons
4
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).
5
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).
6
The IS532 experiment
7
ISOLTRAP@ISOLDE@CERN
RILIS
1.4-GeV protons
from PSB
ISOL beams
ISOLTRAP
8
Where is the Ion of
Interest?
9
10
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).
11
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).
12
IS532 measurements –First measurements in 2014

52,55-58Cr

59Cr
measured with MR-TOF MS

59Cr
provided a successful test of RILIS ionization scheme
measured in the Penning Trap
T.D Goodacre et al., Spectrochimica Acta B (in press)
13
Dedicated chromium beam time in 2016
isotope
59Cr
60Cr
61Cr
62Cr
63Cr
Measured with
Penning Trap/MR-TOF
Penning Trap/MR-TOF
Penning Trap/MR-TOF
Penning Trap/MR-TOF
MR-TOF
T.D Goodacre et al., Spectrochimica Acta B (in press)
Half life (ms)
1050
490
243
206
129
Yield (ions/s)
3E5
2E4
2E3
3E2
30
14
Discussion
15
The mass surface
Z. Meisel et al., Phys. Rev. C 93, 035805 (2015).
16
The mass surface
Preliminary
Z. Meisel et al., Phys. Rev. C 93, 035805 (2015).
17
Comparison to theoretical models
LNPS’ valence space
2d5/2
50
2d5/2
50
1g9/2
40
40
1f5/2
1f5/2
2p1/2
2p1/2
2p3/2
2p3/2
28
*
28
1f7/2
neutrons
*In
1g9/2
1f7/2
protons
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).
18
Comparison to theoretical models
GXPF1A and IMSRG
valence space
2d5/2
50
2d5/2
50
1g9/2
40
40
1f5/2
1f5/2
2p1/2
2p1/2
2p3/2
2p3/2
28
*
28
1f7/2
neutrons
*In
1g9/2
1f7/2
protons
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).
19
Conclusions
20
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
21
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).
22
Acknowledgements
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
23
Thank you for your attention!
24