Thermal bremsstrahlung photons probing the nuclear caloric curve

Authors :: H. Delagrange
Yves Roland Schutz
R. Ostendorf
David D'Enterria
Herbert Löhner
R. Ortega
Laurent Bernard Aphecetche
G. Martinez
Hans Wilschut
F. Fernández
KVI - Center for Advanced Radiation Technology
Laboratoire SUBATECH Nantes (SUBATECH)
Mines Nantes (Mines Nantes)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Source :: Physics Letters B, 538(1-2):PII S0370-2693(02)01973-1, 27-32. ELSEVIER SCIENCE BV, Physics Letters B, Physics Letters B, Elsevier, 2002, 538, pp.27-32
Publication Year :: 2002
Abstract: Hard-photon (E$_{\gamma}>$ 30 MeV) emission from second-chance nucleon-nucleon Bremsstrahlung collisions in intermediate energy heavy-ion reactions is studied employing a realistic thermal model. Photon spectra and yields measured in several nucleus-nucleus reactions are consistent with an emission from hot nuclear systems with temperatures $T\approx$ 4 - 7 MeV. The corresponding caloric curve in the region of excitation energies $\epsilon^\star\approx$ 3{\it A} - 8{\it A} MeV shows lower values of $T$ than those expected for a Fermi fluid.<br />Comment: 13 pages, 3 figures. To appear in Physics Letters B

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