Some Ideas for A Future Plan of

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Some Ideas for A Future Plan of Research at ATLAS
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Favored Experimental Conditions at ATLAS

• (Enhanced) stable beam (Digital) Gammasphere
  (GS)
• Radioactive beam from CARIBU (Digital) GS
• If necessary, combined with FMA, charged-
• particle detector array (e.g., CHICO,
  Microball).
• In the future, GRETINA will also be considered.

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Extend Ultrahigh-spin story to Ho, Dy, Hf
nuclei (search for new collective structures at
ultrahigh spin)
162Hf (proposed)
157,158Er (observed/ measured)
154 (observed/ proposed)
159,160 (observed)
Ho
Dy
Lifetime measurement (quadrupole moment) to
determine the deformation
65hbar!
Paul et al., PRL 98, 012501 (2007).
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Search for 2-phonon (and even multiple-phonon)
octupole bands in Actinides, Lanthanides
0-pn
1-pn
2-pn
Nazarewicz et al., NPA 429, 269 (1984).

• Unsafe Coulomb excitation (multiple-
• neutron transfer) need radioactive target.
• Fu-Ev reaction need radioactive beam
• (CARIBU?).

240Pu
Wang et al., PRL 102, 122501 (2009).
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(?)
()
Search for Tetrahedral Symmetry in Lanthanides,
Actinides
Low-spin Tetrahedral? High-spin Octupole vibrat
ion?
Round-edge pyramid shape
Predicted Tetrahedral magic numbers Zt 16, 20,
32, 40, 56-58, 70, 90-94. Nt 16, 20, 32, 40,
56-58, 70, 90-94.
Wang, Ph.D. thesis, Notre Dame (2007).

• Measure branching ratios.
• Measure dipole transition probabilities
• of interband lines.

Dudek et al., PRL 88, 252502 (2002).
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Identify decay path of SD, TSD structures in Er,
Yb, Hf nuclei
Floating candidate bands observed
previously. 154Er 1 TSD, 1 SD Lagergren et al.,
PRL 87, 022502 (2001). 157Er 2 TSDs 158Er 2
TSDs Paul et al., PRL 98, 012501 (2007). 159Er
1 TSD 160Er 2 TSDs Ollier et al., submitted to
PRC. 160Yb 1 TSD. Aguilar et al., PRC 77,
R021302 (2008). 174Hf 8 TSDs/SDs Djongolov et
al., PLB 560, 24 (2003). Hartley et al., PLB 608,
31 (2005).
Lauritsen et al., PRL 88, 042501 (2002).
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Search for Low-lying SD, TSD (wobbling?) in
n-rich 44Ru

• PES calculations show low-lying (I 20hbar)
  SD/TSD minima and fruitful coexisting shapes in
  n-rich Ru, best cases 110,112Ru...
• We intend to study 108-112Ru. Need to populate up
  to I 30hbar.
• Reactions Safe or unsafe Coulex n-rich Ru beam
  (107-112Ru yieldgt106 from CARIBU) on thick target
  (e.g., 208Pb), or on thin target with
  charged-particle detectors (e.g., CHICO) used.
• Trigger set on target nuclei.

Skalski et al., NPA 617, 282 (1997).
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Collaboration
FSU X. Wang, M. A. Riley, S. Yuan, C.
Teal USNA D. J. Hartley Argonne M. P.
Carpenter, C. J. Chiara, R. V. F. Janssens, F. G.
Kondev, T. Lauritsen, S. Zhu Liverpool (UK) E.
S. Paul, A. J. Boston, H. C. Boston, D. Judson,
P. J. Nolan, J. Revill, C. Unsworth Daresbury
(UK) J. Simpson, J. Ollier Tennessee L. L.
Riedinger Notre Dame A. D. Ayangeakaa, U. Garg,
J. Matta Berkeley P. Fallon, M. K. Petri Lund
(Sweden) I. Ragnarsson Oak Ridge D. Radford,
C.H. Yu iThemba (South Africa) J. F.
Sharpey-Schafer