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Rotational bands in the rare-earth proton
emitters and neighboring nuclei
Darek Seweryniak
Argonne National Laboratory
PROCON-2003
1. Rotational landscape in the rare-earth region.
2. Recoil-Decay Tagging.3. Excited states in the proton emitters
147Tm,141Ho and 131Eu.4. Particle-Rotor calculations.5. GAMMASPHERE+Ball+nWall.6. Excited in 143Ho and neighboring
nuclei.7. Summary and outlook.
CollaborationCollaborationD.Seweryniak, C.N.Davids, M.P.Carpenter, D.Seweryniak, C.N.Davids, M.P.Carpenter,
S.Freeman, A.Heinz, G.Mukherjee, S.Freeman, A.Heinz, G.Mukherjee, A.Sonzogni, J.J.Uusitalo, R.V.F.Janssens, A.Sonzogni, J.J.Uusitalo, R.V.F.Janssens,
T.L.Khoo, F.G.Kondev, T.Lauritsen, T.L.Khoo, F.G.Kondev, T.Lauritsen, C.J.Lister, G.L.Poli, P.Reiter, I.WiedenhoeverC.J.Lister, G.L.Poli, P.Reiter, I.Wiedenhoever
Argonne National LaboratoryArgonne National Laboratory
P.J. Woods, T. DavinsonP.J. Woods, T. DavinsonUniversity of EdinburghUniversity of Edinburgh
J.J. Ressler, J. Shergur, W.B. WaltersJ.J. Ressler, J. Shergur, W.B. WaltersUniversity of MarylandUniversity of Maryland
J.A. Cizewski, K.Y. Ding, N. FotiadesJ.A. Cizewski, K.Y. Ding, N. FotiadesRutgers UniversityRutgers University
Proton drip lineProton drip line
131Eu
141Ho
147Tm
Nilsson diagramNilsson diagram
147Tm
135Tb141Ho
131Eu
145Ho?
Strong couplingStrong couplingCoupling to the deformation axis:
• K is a good quantum number• j precesses around the symmetry axis• Coriolis introduces K-mixing• signature splitting• 4 and enhances K-mixing
R
j
K
KK+1
K+2
K+3
K+1K+2
K+3
K+4
K=1 Coriolismixing
K+4
E2M1
E2
K-band K+1 band
Rotational couplingRotational couplingCoupling to the rotational axis:
• j precesses around the rotational axis• energies similar as in the gs band in the daughter• small deformation, high-j, low-K
Rj
Strong Coriolis interaction
jj+2j+4
j+6
E2
Recoil-Decay TaggingRecoil-Decay Tagging
Prompt rays RecoilsImplants and p decays
GAMMASPHERE
Spatial and timecorrelationsin the DSSD
Excited states in Excited states in 147147TmTm
p (h11/2) p (d3/2)
620||=0.13
GS data - 4 hours
Aye-ball data
141141Ho spectraHo spectra
141141Ho level schemeHo level scheme
7/2-[523] ½+[411]
D. Seweryniak et al., PRL C86(2001)1458
Unexpectedly large
signature splitting!
=0.25(4) Harris
formula
p p
Particle-Rotor Model InputParticle-Rotor Model Input
Tri-axial RotorTri-axial Rotor Woods-Saxon potential with the Woods-Saxon potential with the
universal set of parametersuniversal set of parameters Coriolis attenuation factor 0.85Coriolis attenuation factor 0.85 Proton pairing strength 0.136 MeVProton pairing strength 0.136 MeV Moments of inertia adjusted to the Moments of inertia adjusted to the
2+ energy in the daughter nucleus2+ energy in the daughter nucleus
Coriolis matrix elements are attenuatedby the pairing factor:
u1u2+v1v2
=0.
25-0
.31
=0o -
(-20
o )
=10
0-90
%
=10
0-90
%
=
0-(-
0.06
)
7/2-
9/2-
11/2-
13/2-
15/2-
=
180-
200
exp =0.29, 4=0, =0o
PR model sensitivityPR model sensitivity
141141Ho Particle-Rotor Ho Particle-Rotor calculations calculations
Best fit:
2=0.25E(2+)=190 keV
4=-0.06=-10o
Another fit:
2=0.29E(2+)=140 keV
4=-0.06=-20o
Total Routhian Surface Total Routhian Surface CalculationsCalculations
=0.25 MeV
=0.05 MeV =0.15 MeV
=0.35 MeV
141Ho is soft and develops triaxiality at
higher angular momentum
131131Eu spectraEu spectra
M1M1
E2
h11/2 band
131131Eu level schemeEu level scheme
5/2+[413] or 3/2+[411] ground state?
3/2+[411] band in 159Tb94 after A5/3 scaling gives:
189
72
105
7/2+
5/2+
9/2+
5/2+[413] band in 159Eu96 after A5/3 scaling gives:
237
104
134
7/2+
5/2+
9/2+
We observe 72 keV and 105 keV.Low energy transitions present in the spectrum
suggest the 3/2+[411] assignment
Population of proton rich nuclei Population of proton rich nuclei along the proton drip-linealong the proton drip-line
Z=72154Hf
153Lu152Lu151Lu
150Yb
149Tm148Tm147Tm
150Lu
146Tm
146Er
145Tm
145Ho144Ho143Ho142Ho141Ho140Ho
144Dy143Dy142Dy141Dy140Dy139Dy
143Tb142Tb141Tb140Tb139Tb138Tb
142Gd141Gd140Gd139Gd138Gd137Gd
141Eu140Eu139Eu138Eu137Eu136Eu
CN
CN
CN
CN
136GdCN
pp
p p p
p p
N=82
135Eu131Eu …
50b
300 nb 500 mb
1 out of 10 million rays!
5b
100 mb
p
GAMMASPHEREGAMMASPHEREBall+nWallBall+nWall
http://wunmr.wustl.edu/~dgs/mball/
p,
n
54Fe
P
n
Ball - 96 CsI
nWall 30 NE203
92Mo
Gamma spectraGamma spectra
143Tb(3p)
143Dy(2p1n)
142Dy(2p2n)
63Zn(2p1n) on C
143143Ho level schemeHo level scheme
143Ho(p1n2)
318
508
663
143Ho11/2-
15/2-
19/2-
23/2-
E(2E(2++,0) and ,0) and E(15/2E(15/2--,11/2,11/2--))systematicssystematics
149Tm148Tm147Tm146Tm
146Er
145Tm
145Ho144Ho143Ho142Ho141Ho140Ho
144Dy143Dy142Dy141Dy140Dy139Dy
143Tb142Tb141Tb140Tb139Tb138Tb
142Gd141Gd140Gd139Gd138Gd137Gd
141Eu140Eu139Eu138Eu137Eu136Eu
464
318
203
487
145Er144Er
323 526273
307 521
316 493
515329221
169
145Tm similar to 143Ho!
SummarySummary1.1. Studies of excited states proved to be a very useful Studies of excited states proved to be a very useful
source of complementary information on proton source of complementary information on proton emitters.emitters.
2.2. Ground state band in Ground state band in 147147Tm confirmed and Tm confirmed and extended.extended.
3.3. Lower Lower 22 deformation in deformation in 141141Ho, Ho, 44 and and important. important.
Single –particle configurations in agreement with Single –particle configurations in agreement with adiabatic decay-rate calculations.adiabatic decay-rate calculations.
4.4. Rotational bands in Rotational bands in 131131Eu observed. Fine structure Eu observed. Fine structure confirmed. The 3/2+[411] assignment is favored.confirmed. The 3/2+[411] assignment is favored.
5.5. The hThe h11/211/2 band in band in 143143Ho observed, more to come ….Ho observed, more to come ….
OutlookOutlook
1. Recent upgrades of the FMA implantation station and GAMMASPHERE promise next successful RDT campaign.
2. GAMMASPHERE+FMA will allow to study excited states in other, recently discovered deformed proton emitters such as 117La or 145Tm.
3. GAMMASPHERE+Ball+nWall will allow to fill up considerably the gap between the stability line and the proton drip line.
4. Other methods such as RDT using -delayed proton emitters or isomer studies could also contribute.