structure close to 208 pb
DESCRIPTION
Structure close to 208 Pb. Zsolt Podoly ák. The fragment separator. 370 implanted 212 Pb ions!. Time from production to spectroscopic analysis: ~ 300 ns. fragmentation or fission. Decay studies: -internal (isomers) -beta decay. - PowerPoint PPT PresentationTRANSCRIPT
Structure close to 208Pb
Zsolt Podolyák
The fragment separator
Time from production to spectroscopic analysis: ~ 300 ns
fragmentationor fission
Decay studies:
-internal (isomers)
-beta decay
Very sensitive method
370 implanted 212Pb ions!
M. Pfützner et al., Phys. Lett. B 444 (1998) 32.
Exp. (test) #2: 238U beam
208Hg, 209Tl
Experiment #1
208Pb beam
‘passive stopper’ experiments
Spokesperson: #1,2 Zs. Podolyák, #3 J.J. Valiente-Dobon, G. Benzoni
Analysis by S. Steer (N<=126), N. Al-Dahan (N>126), T.Swan (σ)
Exp. #3: 238U beam
190,192Ta
198,202Ir
203,205,(206)Au
194,196,198Re200Os
Spokespersons: P.H. Regan & J. Benlliure
Analysis by N. Alkhomashi, N. Al-Dahan, G. Farrelly, A.I. Morales et al.,
‘active stopper’ experiments208Pb beam
N=126 nuclei below 208Pb (what was known)
Z=81 Z=80 Z=79 Z=78
206H
g: B
.For
nal e
t al.
Phy
s. R
ev. L
ett.
87(2
001)
212
501.
207T
l: D
. Ecc
lesh
all,
M. J
. L. Y
ates
, Phy
s. L
ett.
19, 3
01 (
1965
).
+
Particle identification
GSI
204Pt 205Au
203Ir
205Au: three proton-hole nucleus
Charged particles
Gammas
Active stopper exp.
Zs. Podolyák et al., Phys. Lett. B 672 (2009) 116.
Shell-model calculations (M.Górska, H.Grawe, H. Maier, A.Brown)
(a)and (d):TBME from L.Rydstrom et al, NPA512(1990)217 (based on Kuo-Brown interaction)
(b) and (c): three TBMEs modified
Δ(d3/2 h11/2; d3/2 h11/2)7- = +135 keV
Δ(s1/2 d5/2; s1/2 d5/2)2+,3+ =+230 keV (monopole only)
Δ(d3/2 h11/2; s1/2 h11/2)6- changed to +0.160 MeV (fit for B(E2)
Good description of energies and B(EL)s
S.Steer et al., Phys. Rev C78 (2008) 061302(R)
πh11/2-2 s1/2
-1
205Au
πh11/2-1 s1/2
-2
πd3/2-1 s1/2
-2
B(E2): 3.1 1.2(2) 1.7 W.u.
Orig. SM Mod. SM
Calc. H. Grawe
203Ir
Orig. SM Mod. SM
Future: further ‘down’ along the N=126 line (acc. exp.)205Au: beta decay from 205Pt => will fix the πs1/2 orbital203Ir: beta decay from 203Os (νg9/2) => will fix the πd3/2,πs1/2,πh11/2 202Os: isomeric decay I=(5),(7),(10)202Os: beta decay of 203Ir (νg9/2)
0+ 0
2+ 1181
4+ 1555
7- 1893
5- 1932
10+ 26738- 2558
8+ 2685
202Os
shel
l mod
el
N>126, Z<82 nuclei (238U beam)
Δq=0
206Hg
208Hg
209Tl
N. Al-Dahan et al.
Shell-model calc. (H. Grawe)TBME: from E.K. Warburton, PRC44, (1991) 233; are based on the Kuo-Herling realistic int.Single particle energies: 207Tl and 209Pb exp.
( νg29/2) states;
2+ mixed with πs-11/2d-1
3/2
B(E2)=1.22 W.u. SM
B(E2)=1.95(39)-1.58(22) W.u. exp.
209Tl: Isomer: 17/2+; ( νg2
9/2) (πs-11/2)
17/2+->13/2+ Δ
13/2+->9/2+ 137 keV
9/2+->7/2+ Δ, allowed M1
7/2+->3/2+ 661 keV
3/2+->1/2+ 324 keV E2(+M1)
B(E2)=0.96 W.u. SM
B(E2)=1.87(22)-1.51(18) W.u. exp.
209Tl: previously from (t,α) and alpha decay.(t,α): C. Ellegaard, P.D. Barnes and E.R. Flynn, Nucl. Phys. A259 (1976) 435.
),2()2,()2,2(),(4
1),( NZBNZBNZBNZBNZVpn
~1/(Δl+Δn)
N>126, Z<82 nuclei
Mass measurement of 208Hg (GSI storage ring)
L. Chen et al., PRL102 (2009) 122503.
proton neutron
i13/2 i11/2
g9/2 g9/2
Z=82 N=126
s1/2 p1/2
d3/2 f5/2
N.
Al-
Dah
an e
t al. s
ubm
itte
d t
o P
RL
T1/2=10(2) sBeta decay:
A.I. Morales, J. Benlliure et al.,
Acta Phys. Pol. B 40, 867 (2009)
Isomer:
S.J. Steer et al.,
Int. J. Mod. Phys.
E18, 1002 (2009)
Shell model: M. Gorska
An example of an N=125 nucleus: 204Au
1-: 186, 336, 437, 686 keV
Seniority isomers in n-rich Pb isotopes
Pb isotopes
S350 experiment – 2.5g/cm2 Be target, 2g/cm2 S1 degrader, 0.7g/cm2 S2 degrader - Setting on 215Pb
214,216Pb isotopes: neutron g29/2 8+ isomers
Partial statistics
Preliminary
J-J. Valiente-Dobon, G. Benzoni,
Sept. 2009
E.Simpson, J.A. Tostevien et al.
Population of isomers by two-proton knockout reaction in 206Hg
Total
10+
5- (with feeding)
Isomeric ratios fig.
Exp. Theory
3.1 4.7 -> 4.3
22 19 -> 18
Summary:
Info through isomeric decays in:
- N=126: 205Au, 204Pt, 203Ir
- N=128: 208Hg, 209Tl
Comparison with shell-model
-New measurements 214,216Pb
-future: higher beam intensity
AIDA
DESPEC
The RISING Collaboration