Penning-trap based mass and decay
spectroscopy of exotic nuclei
Ari Jokinen

Tandem trap (at JYFL)
Mass measurements
Trap-assisted spectroscopy

CPT, ISOLTRAP, JYFLTRAP, LEBITSHIPTRAP, TITAN, TRIGA-TRAP, …

Purification & measurement

Purification trap
mass-selective buffer
gas coolingPrecision trap
TOF-ICR method

120

Basic equations formass determination

91

100

A=91

Tc
SELECT 91Tc+Counts80

fc =6040

91f c,refm - me=fc
mref - me

Mo2091Ru

01181750 1181800 1181850 1181900 1181950 1182000

Frequency (Hz)Routinely M/∆M ~ 105
Space charge limit ~105
Good/Bad ~ 10000

1 q⋅ ⋅B
2π m

Routinely few keV
If required few tens of eV (δm/m < 1·10-8)

IGISOL3: Spectroscopy of exotic isotopes of all elements
Ion guide technique

Targetp + 238U fission
Heavy and light ion fusion
Transfer reactions
Laser ionization

Extractor

SextuPoleIon Guide(SPIG)BeamJYFLTRAP data in 132Sn region

140Te
136Sb
135Sn
131In
128Cd

J. Hakala et al., PRL 109 (2012) 032501

Mass differences
Two-neutron shell gap for N=82

Odd-even mass staggeringShell gap
82

J. Hakala et al., PRL 109 (2012) 032501

Spherical EDF calculations around 132Sn

Spherical approach

Sn isotopes withdifferent pairing options
J. Hakala et al., PRL 109 (2012) 032501

Spherical EDF calculations around 132Sn

Spherical approach

Sn isotopes withdifferent pairing options
J. Hakala et al., PRL 109 (2012) 032501

Isomeric states, T1/2 > 100 ms

A. Kankainen et al., PRC 87 (2013) 024307

Dipole Ramsey cleaning for isomeric purification
281(4) keV

T. Eronen et al., NIM. B 266 (2008) 4527

Single-particle states close to 132Sn
SYSTEMATICS of the 11/2- state

Odd neutron in the1h11/2 shell
Cd isomers
relocated  trend
similar to Teisomers

82
1h11/2
3s1/2
2d3/2
2d5/2
1g7/2
50

SYSTEMATICS of the 1/2- state

In (Z=49)
proton-hole in the
2p1/2 shell
Old Q-value basedenergies corrected

50
1g9/2
2p1/2
1f5/2
2p3/2
28

A. Kankainen et al., PRC 87 (2013) 024307

PT measurements of fission fragments

A. Kankainen, J. Äystö and A. Jokinen, J. Phys. G 39 (2012) 093101

AME vs. PT data (n-rich nuclei)

2003

2011 upd.

=(N-Z)/2=(N-Z)/2A. Kankainen, J. Äystö and A. Jokinen, J. Phys. G 39 (2012) 093101

PI-ICR●Count revolutions + final phase●Spatially resolving MCP•••

Phase-Imaging Ion Cyclotron Resonance technique

Benefits compared to TOF-ICR:– 25x faster– 40x resolving power
Well suited for short-lived ions
Developed by S. Eliseev, MPIK Heidelberg and implemented at
SHIPTRAP, GSI
S. Eliseev et al., PRL 110, 082501 (2013)
S. Eliseev et al., Appl. Phys. B 114, 107 (2014)

Trap-assisted spectroscopyExample: Purification in A=115

Isomer separation - Decay study of 100Nb∆E=314(22) keV
JYFLTRAP

Similar half-lives
Mixed decay schemes

C. Rodríguez Triguero et al., J. Phys. G: Nucl. Part. Phys. 39 (2012) 015101

Isomer separation - Decay study of 100Nb∆E=314(22) keV
JYFLTRAP

Similar half-lives
IsomerMixed decay schemes

Ground state

C. Rodríguez Triguero et al., J. Phys. G: Nucl. Part. Phys. 39 (2012) 015101

Multiple loading
Repeated cleaning and mixing with a new ion cloud increase of ions of interest in each cycle
OFF-LINE

t½ = 2228.3(27) msMultiple loading: Ex. T1/2(26Si)


Beta counting -> requires a clean sample
Measurement cycle requires 25 s decay period
Accumulation in RFQ, bunches sent to purification trap
Purification trap saturates in 300 ms -> use multiple loading
In 25 s 8 cycles and 6-7 times more 26Si than in single loadingt½ = 2228.3(27) ms
26Si, EPJ A 37 (2008) 151

42Ti, PRC 80 (2009) 035502
30S, EPJ A 47 (2010) 40

31S, EPJ A 48 (2012) 155

A new era of post-trap spectroscopy:
DTAS detector for DESPEC at IGISOL-4••••16 (+2) NaI(Tl) modules
5” PMT (50% light collection)
Commissioning Valencia (Jan/2014)
IGISOL-4 run (Feb-Mar/2014)•

JYFLTRAP provides high purity
beams
Measurements of beta decay
strength of 100Tc
18 nuclei relevant for precise
predictions of neutrino spectrafrom reactors (8 days)••

IGISOL - 4
Test ion sources
K130 beam line
Dipole magnet

RFQ
Laser line

MCC30p/d cyclotron

IGISOL front-end
JYFLTRAPSummaryPT mass measurements have contributed to:• Better understanding of the binding of exotic nuclei• Nuclear structure information• Shell evolution, shape changes, new regions ofdeformation, pairing• Single-particle energies• CVC hypothesis and the unitarity of CKM• Rare decays (Xth-forbidden beta decays, ββ, ECEC,)• Nuclear astrophysics• Applications, etc
Trap-assisted spectroscopy• has improved the spectroscopic sensitivity• Improved the quality of the data
Outlook• Complementary: rings, MR-TOF, …
• Laser techniques• Faciility upgrades

THANK YOU FOR YOUR ATTENTION !