Program - Brookhaven National Laboratory

types understudy in the PWR cycle showed good safety inherent feature with the exception of the some
MOXAm assemblies which have a positive void coefficient in specific configurations, which could not be
consistent with safety features.
Session HF Experimental Facilities and Techniques
Tuesday March 5, 2013
Room: Central Park East at 3:30 PM
HF 1 3:30 PM
Verification of the Thermodynamic Model in Nuclear Fission: the New Spectrometer
FIPPS
Herbert Faust, Ulli Koester, Abdelaziz Chebboubi, Aurelien Blanc
Institut Laue-Langevin, Grenoble, France
Gregoire Kessedjian, Christophe Sage
LPSC Grenoble, France
Thomas Materna, Stefano Panebianco
CEA Saclay, France
The thermodynamic model provides the entry state population in fission fragments in defining excitation
energy and spin distributions as function of fragment mass and charge. In the same way the distribution
functions for the decay products of excited fragments are provided (in particular prompt gamma and
neutron decay). The parameters relevant to the thermodynamic descriptions are the level density, which
is taken from low energy nuclear physics data, and a nuclear temperature, which can be derived from
a single fragment kinetic energy measurement. In the presentation we will review the statistical model
for excitation and spin distributions of fragments, and the distributions for decay particles as function of
mass, charge and fragment kinetic energy. We will present a new spectromenter which aims to provide the
observables Y(A,Z,E*,J), which characterize fully a fission event. The new spectrometer will consist of a
gamma array of HP germanium detectors, and a gas filled magnet for the determination of Y(A,Z,Ekin),
from which the various distribution functions and the decay characteristics are derived. First experiments
on a gas filled magnet device will be presented, and the the approach for the calculation of the ion tracks
in the magnet will be given.
HF 2 4:00 PM
Modular Total Absorption Spectrometer at the HRIBF (ORNL, Oak Ridge)*
M. Wolińska-Cichocka, K.P. Rykaczewski, M. Karny, R.K. Grzywacz, C.J. Gross, J. Johnson
ORNL, Oak Ridge, TN 37830, USA
A. Fijalkowska
University of Warsaw, Warsaw, PL 00-681, Poland
D. Miller
University of Tennessee, Knoxville, TN 37996, USA
B.C. Rasco, E. Zganjar
Louisiana State University, Baton Rouge, LA 70803, USA
The Modular Total Absorption Spectrometer (MTAS) array will be presented. MTAS has been designed,
constructed and applied to the decay studies of 238 U fission products at the Holifield Radioactive Ion Beam
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