Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

A detailed study is undertaken, using various techniques, in deriving expansions of integrals containing the Fermi or the symmetrized
Fermi distributions. The results are presented in a mathematically compact form and consist of generalizations and extensions
of previously known expansions. The relevance of the results to quantities of interest in nuclear physics is recalled and
particular attention is paid to the so-called exponentially small terms which may play an essential role in certain cases.
NTIS
Integrals; Integral Calculus; Series Expansion
20000064119 Joint Inst. for Nuclear Research, Bogolyubov Lab. of Theoretical Physics, Dubna, USSR
Caloric curve and multifragmentation in heavy ion collisions at intermediate energies
Parvan, A. S.; Gudima, K. K.; Toneev, V. D.; Dec. 31, 1998; 27p; In Russian; In English
Report No.(s): DE99-607993; JINR-R-7-98-33; No Copyright; Avail: Department of Energy Information Bridge
Based on a canonical ensemble treatment, a unique description of multifragmentation and equation of state for isospin non-degenerated
nuclear matter is constructed within a statistical model for fragmenting nuclear system. The free energy of primary fragments
is defined by a liquid-drop approximation of the statistical multifragmentation model. Exact solutions for the canonical
partition function of the decaying nuclear system are obtained by means of recurrent relations. For certain thermodynamic parameters
this model exhibits a phase transition of the liquid-gas type. Fragment multiplicity distributions as well as temperature and
volume dependence of thermodynamic quantities are calculated. The caloric curve characterizing the phase transition under question
is discussed. The effective parameter (tau) of the fragment charge distributions and the average multiplicity of intermediate
mass fragments are compared with appropriate experimental data from heavy ion collisions.
NTIS
Nuclear Physics; Fragmentation; Ionic Collisions; Equations of State
20000064706 Saclay Research Centre, Dept. d’Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l’Instrumentation
Associee, Gif-sur-Yvette, France
Study of the effect of (sup 11)Be halo on the sub-coulombian fusion
Felou Youmbi, V.; Dec. 11, 1996; 148p; In French; In English
Report No.(s): DE99-609718; CEA-DAPNIA-SPHN-96-04T; No Copyright; Avail: Department of Energy Information Bridge
Fission cross sections of (sup 9,11)Be + (sup 238)U systems are measured in the energy range of the coulomb barrier. These
measures allow the study of neutron halo effect on sub coulombian fusion. (sup 9,11)Be beams are obtained by fragmentation at
the GANIL facilities. The fusion between incident particle and the target nucleus leads to a compound nucleus which disappears
by fission. The FUSION detector is used to detect the fission fragments by coincidence. We present some calculations of potential
barriers by using Wong formula. The nucleus-nucleus interaction is simulated by a double convolution between the nucleus density
and the effective M3Y interaction. In a more realistic framework ECIS94 code calculates the fusion cross section by using
a coupling formalism. Theoretical values and experimental results are compared. We get a good agreement for (sup 9)Be + (sup
238)U system and an unusual behaviour appears for (sup 11)Be + (sup 238)U system.
NTIS
Halos; Nuclear Physics; Beryllium Isotopes; Fission
20000066582 Grand Accelerator National d’Ions Lourds, Caen, France
Study of the (sup 7)Be(p, (gamma))(sup 8)B and (sup 7)Li(n, (gamma))(sup 8)Li capture reactions using the shell model
embedded in the continuum
Bennaceur, K.; Ploszajczak, M.; Nowacki, F.; Okolowicz, J.; Feb. 28, 1999; 49p; In English
Report No.(s): DE99-633343; GANIL-P-99-02; No Copyright; Avail: Department of Energy Information Bridge
The realistic shell model which includes the coupling between many-particle (quasi-)bound states and the continuum of oneparticle
scattering states is applied to the spectroscopy of mirror nuclei: (sup 8)B and (sup 8)Li, as well as to the description of
low energy cross sections (the astrophysical S factors) in the capture reactions: (sup 7)Be(p,(gamma))(sup 8)B and (sup
7)Li(n,(gamma)) (sup 8)Li.
NTIS
Lithium Isotopes; Beryllium Isotopes; Boron Isotopes; Nuclear Physics
20000066626 Grand Accelerator National d’Ions Lourds, Caen, France
Multiscale fluctuations in nuclear response
Lacroix, D.; Chomaz, P.; Jan. 31, 1999; 43p; In English
Report No.(s): DE99-633342; GANIL-P-99-01; No Copyright; Avail: Department of Energy Information Bridge
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