Spectroscopy of the heaviest Nuclei

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Spectroscopy of the heaviest Nuclei
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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
R-D Herzberg
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Deformed orbitals
Problems No gap at Z100 or 102 No gap at
N152 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
R-D Herzberg
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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.
r0 0.16 fm-3
Neutron density
R-D Herzberg
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Today
RDH PTG, Prog Part Nucl Phys 61 (2008) 674
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Experimental Tools

• Decay spectroscopy
• In-beam spectroscopy
• c.f. Eddie Parr talk today
• Gamma Rays
• Conversion Electrons

R-D Herzberg
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Systematics Z99 Es
F.P. Hessberger et al., EPJA 26 (2005) 233
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Single particle Z99
7/2 ? 3/2- ?
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Neutrons e.g. N149
c.f. TASIspec Poster LL Andersson
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Experimental Tools

• Decay spectroscopy
• In-beam spectroscopy
• c.f. Eddie Parr talk today
• Gamma Rays
• Conversion Electrons

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Internal Conversion
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Spectrum
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Conversion Coefficients
103 102 10 1 0.1 10-2
Z100
M1 K E2 K
e- dominate
alpha
a 1
g dominate
100 200 300
400 500
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Conversion Coefficients
Absolute
Normalised
E 200 keV Z 102 BrICC (T. Kibédi et
al., NIMA 589 (2008) 202)
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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

9/2-734 7/2624
R. Chasman et al, Rev Mod Phys 49 (1977) 833.
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253No Gammasphere
P. Reiter, PRL 95 (05) 032501
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253No Jurogam
11400 Recoils
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Levelscheme
S. Moon, PhD thesis
EPJA submitted
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SACRED Data
T. Page, PhD thesis
1840(40) Recoils
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Moment of Inertia
M. Bender et al., Skyrme-HFB priv. comm.
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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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SAGE and JUROGAM II
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SAGE
Ge opening angles
Beam
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Shielding
BT

• Photomultiplier tubes are sensitive to magnetic
  fields
• Shields Weaken
• redirect stray magnetic field

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Capability

• 106 Chn Ge _at_ 30-50 kHz
• 90 Chn Si _at_ 30-50 kHz
• Triggerless TDR DAQ
• no common dead time!
• No bottlenecks

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Digital Electronics
50 kHz
40 kHz
30 kHz
20 kHz
10 kHz
Early implementation still needs pileup and
Compton Suppression
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Experiments

• SHE
• 253No, 251Md, 255Lr,
• 254No, 256Rf,
• Shape Coexistence
• 184-190Pb, 180-188Hg, light Po,Bi etc
• E0 from multiphonon states
• Etc

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SAGE
Status April 2nd
Philippos Juha Janne
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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

• 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