Lifetime Measurements with the Doppler Shift Attenuation Method Using a Thick Homogeneous Production Target — Verification of the Method

A. Ertoprak , B. Cederwall , U. Jakobsson , B.M. Nyakó , J. Nyberg , P. Davies , M. Doncel , G. De France (1) , I. Kuti , D.R. Napoli , R. Wadsworth , S.S. Ghugre , R. Raut , B. Akkus , H. Al-Azri , A. Algora , G. De Angelis , A. Atac , T. Bäck , A. Boso , E. Clément (1) , D.M. Debenham , Zs. Dombrádi , S. Erturk , A. Gadea , F. Ghazi Moradi , A. Gottardo , T. Huyuk , E. Ideguchi , G. Jaworski , H. Li , C. Michelagnoli (1) , V. Modamio , M. Palacz , C.M. Petrache (2) , F. Recchia , M. Sandzelius , M. Siciliano , J. Timár , J.J. Valiente-Dobón , Z.G. Xiao

1 GANIL - Grand Accélérateur National d'Ions Lourds
2 CSNSM - Centre de Sciences Nucléaires et de Sciences de la Matière

Doppler Shift Attenuation Method (DSAM) analysis of excited-state lifetimes normally employs thin production targets mounted on a thick stopper foil (“backing”) serving to slow down and stop the recoiling nuclei of interest in a well-defined manner. Use of a thick, homogeneous production target leads to a more complex analysis as it results in a substantial decrease in the energy of the incident projectile which traverses the target with an associated change in the production cross section of the residues as a function of penetration depth. Here, a DSAM lifetime analysis using a thick homogeneous target has been verified using the Doppler broadened lineshapes of γ rays following the decay of highly excited states in the semi-magic (N = 50) nucleus 94Ru. Lifetimes of excited states in the 94Ru nucleus have been obtained using a modified version of the LINESHAPE package from the Doppler broadened lineshapes resulting from the emission of the γ rays, while the residual nuclei were slowing down in the thick (6 mg/cm2) metallic 58Ni target. The results have been validated by comparison with a previous measurement using a different (RDDS) technique.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

A. Ertoprak, B. Cederwall, U. Jakobsson, B.M. Nyakó, J. Nyberg, et al.. Lifetime Measurements with the Doppler Shift Attenuation Method Using a Thick Homogeneous Production Target — Verification of the Method. The Zakopane Conference on Nuclear Physics “Extremes of the Nuclear Landscape”, Aug 2016, Zakopane, Poland. pp.325, ⟨10.5506/APhysPolB.48.325⟩. ⟨in2p3-01769762⟩