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R-D Herzberg 252,253,254 No 250 Fm Spectroscopy of the heaviest Nuclei
R-D Herzberg
252,253,254No
250Fm
Spectroscopy of the heaviest
Nuclei
Overview
• Transfermium Nuclei
• Internal Conversion
• In-beam g and CE spectroscopy:253No
• The SAGE Spectrometer
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Shell Positions for 298114
From M. Bender et al., PRC 60 (1999) 034304
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Deformed orbitals
Problems:
No gap at Z=100 or 102
No gap at N=152
Trace to position of high-j
Orbitals?
p i13/2 n j15/2
M Bender, e.g. in
A. Chatillon et al, EPJA30, 06, 397
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Different Skyrme Forces
Nuclear EOS from
18 different Skyrme
parametrisations
All agree around
nuclear density
S. Typel, B.A. Brown,
PRC 64 027302.
Neutron density
r0 = 0.16 fm-3
Today
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RDH & PTG, Prog Part Nucl Phys 61 (2008) 674
Experimental Tools
• Decay spectroscopy
• In-beam spectroscopyc.f. Eddie Parr talk today
– Gamma Rays
– Conversion Electrons
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Systematics Z=99: Es
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F.P. Hessberger et al., EPJA 26 (2005) 233
Single particle Z=99
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7/2+ ? 3/2- ?
Neutrons e.g. N=149
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c.f. TASIspec
Poster LL Andersson
Experimental Tools
• Decay spectroscopy
• In-beam spectroscopyc.f. Eddie Parr talk today
– Gamma Rays
– Conversion Electrons
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Internal Conversion
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Electron Wavefunction
Spectrum
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Conversion Coefficients
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Z=100
a = 1
e- dominate
g dominate
M1
K
E2
K
alp
ha
103
102
10
1
0.1
10-2
100 200 300 400 500
Conversion Coefficients
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0
5
10
15
20
25
30
tot K L1 L2 L3 M
E1
M1
E2
M2
E3
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
K L1 L2 L3 M
Absolute Normalised
E = 200 keV Z= 102 BrICC (T. Kibédi et al., NIMA 589 (2008) 202)
Advantages of ICE
• Multipolarity and Parity directly
observable from subshell ratios
• Mixing ratios directly accessible
• Low energy transitions observable
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253No: 151 neutrons
• Ground state 9/2-
• Excited state 7/2+
Rotational band
observed at
Gammasphere,
assigned 7/2+
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R. Chasman et al, Rev Mod Phys 49 (1977) 833.
9/2-[734]
7/2+[624]
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253No Gammasphere
P. Reiter, PRL 95 (05) 032501
253No Jurogam
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M1
11400 Recoils
Levelscheme
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EPJA submitted
S. Moon, PhD thesis
SACRED Data
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1840(40) Recoils
T. Page, PhD thesis
Moment of Inertia
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M. Bender et al.,
Skyrme-HFB
priv. comm.
Conclusions
• Observed band is built on g.s. 9/2-[734]
• Branching ratios were key
• Electron Spectroscopy is possible
• No band built on 7/2+ observed (yet)
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SAGE
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S(ilicon) A(nd) GE(rmanium) spectrometer
RITU GREATJUROGAM II
Si detector
Fully instrumented with digital electronics
Beam
Clovers
Phase I
SAGE and JUROGAM II
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SAGE
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Beam
Ge opening
angles
Shielding
Photomultiplier
tubes are sensitive
to magnetic fields
Shields: Weaken
& redirect stray
magnetic field
B[T]
Capability
• 106 Chn Ge @ 30-50 kHz
• 90 Chn Si @ 30-50 kHz
• Triggerless TDR DAQ
– no common dead time!
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Digital Electronics
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10 kHz
20 kHz
30 kHz
40 kHz
50 kHz
Early implementation – still needs pileup and Compton Suppression
Experiments
• SHE:
• 253No, 251Md, 255Lr, …
• 254No, 256Rf, …
• Shape Coexistence:
• 184-190Pb, 180-188Hg, light Po,Bi etc…
• E0 from multiphonon states
• EtcR-D Herzberg
SAGE
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Status April 2nd
Philippos Juha Janne
Summary
• Combined Electron and Gamma Ray
spectroscopy is a very powerful tool
• The SAGE Spectrometer will be
commissioned in the summer
• Experiments welcome in the
September PAC!
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SAGE Collaboration
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University of Liverpool, UK
R.-D. Herzberg, J. Pakarinen, P. Papadakis,
L.L. Andersson, P.A. Butler, R.D. Page,
J.R. Cresswell, D.A. Seddon, J. Thornhill,
D. Wells
University of Jyväskylä, Finland
P.T. Greenlees, P. Jones, R. Julin,
P. Rahkila, J. Sorri
STFC Daresbury Laboratory, UK
J. Simpson, P.J. Coleman-Smith,
I.H. Lazarus, S.C. Letts, V.F.E. Pucknell
