Eur. Phys. J. A (2006) 28: 161-171
https://doi.org/10.1140/epja/i2005-10277-9

Heavy Ion Physics

Constraints on the time scale of nuclear breakup from thermal hard-photon emission

¹ Grup de Fısica de les Radiacions, Universitat Autònoma de Barcelona, 08193, Catalonia, Spain
² Subatech (Ecole des Mines, CNRS-IN2P3, Université de Nantes), BP 20722, 44307, Nantes, France
³ GANIL, Grand Accélérateur National d'Ions Lourds, IN2P3-CNRS, DSM-CEA, 14076, Caen Cedex 5, France
⁴ Institute of Nuclear Physics, 20568, Rez, Czech Republic
⁵ Institut de Fısica Corpuscular (CSIC, UV), 22085, 46071, València, Spain
⁶ Kernfysisch Versneller Instituut, 9747 AA, Groningen, The Netherlands
⁷ Institut of Experimental Physics, Warsaw University, 00681, Warsaw, Poland
⁸ Institut für Kernphysik, Forschungszentrum Jülich, D-52457, Jülich, Germany

^* e-mail: ortega@pi0.physi.uni-heidelberg.de

Received: 30 August 2005
Accepted: 2 May 2006
Published online: 19 June 2006

Abstract

Measured hard-photon multiplicities from second-chance nucleon-nucleon collisions are used in combination with a kinetic thermal model to estimate the breakup times of excited nuclear systems produced in nucleus-nucleus reactions at intermediate energies. The obtained nuclear breakup time for the ¹²⁹Xe + ^nat Sn reaction at 50 A MeV is Δτ ≈ 100-300 fm/c for all reaction centralities. The lifetime of the radiating sources produced in seven other different heavy-ion reactions studied by the TAPS experiment is consistent with Δτ ≈ 100 fm/c, such relatively long thermal photon emission times do not seemingly support the interpretation of nuclear breakup as due to a fast spinodal process for the heavy nuclear systems studied.