Answering Questions of Nuclear
and Astrophysics with Mass
Measurements from ISOLTRAP
Susanne Kreim
June 3rd 2014

CERN, Geneva, Switzerland
Max-Planck-Institut für Kernphysik, Heidelberg, GermanyPhysics with ISOLTRAP 2011-2014
Isomers
Nuclear astrophysics
Magic numbers Pairing interaction
Neutrino physics Collective phenomena
190,193Tl?

224-233Fr
223-229Rn
110Cd,Pd

99,100Rb
80-82Zn

96,97Kr

54Ca
53K
M. Wang et al., Chinese Phys. C 36, 1603 (2012)
Particlezoo.net

D. Neidherr et al., Phys. Rev. Lett. 102, 112501 (2009)
S. Naimi et al., Phys. Rev. Lett. 105, 032502 (2010)
D. Fink et al., PRL 108, 062502 (2012)
R. N. Wolf et al., PRL 110, 041101 (2013)
F. Wienholtz et al., Nature 498, 346 (2013)
J. Stanja et al., Phys. Rev. C 88, 054304 (2013)
V. Manea et al., Phys. Rev. C 88, 054322 (2013)
S. Kreim et al., Phys. Rev. C, submitted

Overview
BN , Z   Nmn  Zmp  mN , Z c 2
Measurements with relative uncertainties of 10-6 required for insight intonuclear structre Special tools needed

Binding energy comprises information on all underlying interactions
 How can we identify different contributions?

Observations need interpretation
 Examples 54Ca, 53K, 82Zn, 233Fr

Nuclear theory for comparison and prediction (?)
3

Penning alone in New York

8 million inhabitants
many with the similar weight
Goal: identify the few with exactly the same
mass, evacuate all others
Measure their mass with high precision4Challenges for Short-Lived Nuclides

Challenges at the outskirts of the nuclear chart: Half-lives tens of ms Minute production rates
 High yield of contaminating ions3290 nuclides
Data from: AME 2011 preview (28.04.2011)
G. Audi, M. Wang,
private communication

5

The ISOLTRAP Experiment

M. Mukherjee et al., Eur. Phys. J A 35, 1 (2008)
R. N. Wolf et al., NIM A 686, 82 (2012)

preparation measurement

Detection Techniques
Penning-trap mass spectrometry

Multi-reflection time-of-flight mass spectrometry

39K

350 rev. ≈ 0.5km
δm/m ≈ 3•10-7

52Cr

52K
52Ca

80 ions in 35 minutes!
δm/m = 4•10-8

S. Kreim et al., NIMB 317, 492 (2013)

7R. N. Wolf et al., NIM A 686, 82 (2012)
R. N. Wolf et al., IJMS 349-350, 123 (2013)

Physics from the Mass Surface
Binding energy -> scale of GeV
 Structural information hidden

Apply filters -> most common two-neutron separation energy
S2n ( N , Z )  E ( N  2, Z )  E ( N , Z ) Shell structure of nuclei
 Identify different contributions of interaction

http://www.google.de/imgres?imgurl=http%3A%2F%2Fdownload2.artensoft.com%2Fartensoft_com%2FArtensoftPhotoMosaicWizard%2Fgallery%2FCat_3000Pieces_3000x3045.jpg&imgrefurl=http%3A%2F%2Fwww.artensoft.de%2FArtensoftPhotoMosaicWizard%2Fgallery.php&h=3045&w=3000&tbnid=3EnV8o5IysJMMM%3A&zoom=1&docid=BSnNtf8yXupoRM&ei=RL6AU8S2JsT34QTX8ICAAw&tbm=isch&iact=rc&uact=3&dur=1470&page=1&start=0&ndsp=27&ved=0CF4QrQMwAgNeutron-Rich Calcium Isotopes

On the mass surface, no clear signature for N=32
visible, only calcium and potassium chain show
indication

High-precision mass measurements of 53,54Ca using
ISOLTRAP‘s MR-TOF MS

F. Wienholtz et al., (2013) in press

Magic Number at N=32
ISOLTRAP data on ground-state
properties cleary establish N=32
magic number
Agreement with predictions based on
3-body forces
 EDF calculations cannot reproduce
N=32 closure

Highest shell gap of N=32 for calcium

Plot omitted from online version

10F. Wienholtz et al., Nature 498, 346 (2013)
J. Erler et al., Nature 486, 509 (2012)
C. Forssén et al., Phys. Scr. T 152, 014022 (2013)

Potassium Isotopes
51-53K masses determined with ISOLTRAP

charge radii measured to 51K
Shell gap at N=32 confirmed
Open-shell nuclei: Coupled-cluster calculations predicted spin inversion and re-inversion up to 51K
 Gorkov-Green's function theory: 2- and 3-body interactions from chiral effective field
theory fitted to few-body systems

Plot omitted from online version

V. Somà et al., arXiv:1312.2068v1 (2014)
G. Hagen , Private Communication (2013)
K. Kreim, PLB (2014)

OES of Fr and Ra Isotopes
222,224,226-233Fr and 233,234Ra measured

Mass and half-life of 233Fr for the first time
Odd-even staggering of masses due topairing interaction
 Even nuclides more boundM. Bender et al., EPJA 8, 59 (2000)

S. Kreim et al., PRC (2014) submitted

Pairing Correlation and Deformation
Enhanced staggering of empirical pairing gap towards N=146
Can contributions from pairing and deformation be disentangled?

Compare to calculations excluding pairing (HF) and including deformation(HFB) following ansatz from Satula et al., PRL 81, 3599 (1998)

S. Kreim et al., PRC (2014) submitted13

Shell Gap Filter
D2 N = S2 N (N, Z)- S2 N (N + 2, Z)

M. Wang et al., Chinese Phys. C 36, 1603 (2012)14

N=50 Shell Gap
Size of N=50 shell gap for doubly-magic 78Ni?
Mass of 82Zn most exotic determination of shell gap
Overall linear decrease
Bumpy structure coming from correlations

Plot omitted from online version

R.N. Wolf et al., PRL 100, 041101 (2013)
K. Sieja and F. Nowacki, PRC 85, 051301 (2012)15

82Zn and Neutron Stars
Outer crust of neutron stars is a possible
birthplace of the heavy elements
At a given pressure, modeling composition
depends mainly on the binding energy of thenucleus!
Depth profile through experimental masses
and mass models as input for equation ofstate
82Zn most exotic nuclei measured for crustal

composition excluded from crust
Composition profile constrained deeper byexperimental data
J. M. Pearson et al., Phys. Rev. C 83 (2011)
R. N. Wolf et al., PRL 110, 041101 (2013)16

Crustal Composition
25 different nuclear mass models havebeen tested and all now exclude 82Zn
from the outer crust of a neutron star
Validate that up to a density of 5*1010
g/cm3, the crustal composition isdetermined only by experimental datawith 80Zn being the corresponding
nucleus
Magic neutron shells N=50 and N=82
are the dominating effect of nuclear
structure regarding the crustal
composition

S. Kreim et al., IJMS 349-350, 63 (2013)17

P. Ascher, D. Atanasov,
G. Audi, D. Beck, K. Blaum,
Ch. Böhm, G. Bollen,
Ch. Borgmann, M. Breitenfeldt,
R. B .Cakirli, T. E. Cocolios,
S. Eliseev, T. Eronen,
S. George, F. Herfurth,
A. Herlert, D. Kisler

J. Kluge, M. Kowalska, S. Kreim,
Yu. A. Litvinov, D. Lunney,
V. Manea, E. Minaya Ramirez,
S. Naimi, D. Neidherr,
M. Rosenbusch, S. Schwarz,
L. Schweikhard, J. Stanja,
M. Wang, A. Welker,
F. Wienholtz, R. Wolf, K. Zuber

18

Conclusions
Mass measurements with ISOLTRAP address topics ofnuclear structure far away from stability
 54Ca - test bench for calculations using 3-body forces 53K – test bench for open-shell calculations
 233Fr – challenging to quantify contributions to OES
T. Otsuka et al., PRL 105, 032501 (2010)
S. Rosswog

High-precision mass values constrain neutron-star models
 82Zn most exotic nucleus yet Further mass measurements desired, e.g. Pd isotopes

The implementation of a MR-TOF MS has
openend a wide range of possibilities atISOLTRAP Versatile device: mass spectrometry and insource laser spectroscopy
 Similar work at GSI and RIKEN

R. N. Wolf et al., NIM A 686, 82 (2012)