Excited-state g-factor measurements: Recoil in Vacuum with CARIBU beams

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Excited-state g-factor measurementsRecoil in
Vacuum with CARIBU beams
Andrew Stuchbery Department of
Nuclear Physics, The Australian National
University Canberra, ACT 0200, Australia
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• Physics goal nuclear structure between 100Sn
  and 132Sn

An example g factors of n-rich isotopes between
Z40 and Z50. Why are some g(2) smaller than
in the stable isotopes? Use RIV on CARIBU beams
to extend and improve precision of data.
Simultaneous measurement of B(E2) and g factor
252Cf Gammasphere A.G. Smith et al. PLB 591, 55
(2004)
Behavior of neutron-rich g factors
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RIV g-factor measurements concept

• g factors from a B(E2) experiment
• Measure azimuthal angular correlations
  Gammasphere Hercules (say)

Attenuation coefficient due to RIV contains
information about the nuclear moment
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RIV example with weak radioactive beams 136Te
1. Apparatus ClarionHyball at HRIBF
2. Correlation data give Gk values
3. Extracting g factors from Gk values
Technique applicable for lifetimes 1 ps lt ? lt
100 ps
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RIV in the A 100 region _at_ ANU
Proof of concept and field calibration 2 MeV/A
Ru and Pd beams
Heliotrope (poor mans CD)
4 Ge detectors
Azimuthal angular correlations
Extracted attenuation coefficients
Lines are empirical fits to where An
excellent model fit can also be obtained
104Ru
96Ru
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Summary

• Behavior of g factors in n-rich nuclei near A100
  contrasts with stable isotopes and is not well
  understood
• RIV experiments measure azimuthal angular
  correlations under conditions similar to a B(E2)
  measurement
• Our understanding of the RIV fields is sufficient
  to make g-factor measurements on cases accessible
  with CARIBU