Fission Product Yield Data for the Transmutation of Minor Actinide ...

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4.6. FISSION YIELDS IN NUCLEON INDUCED REACTIONS
AT INTERMEDIATE ENERGIES
Results are presented of an activation
experiment on proton induced fission of nat W, 197 Au,
nat Pb, 208 Pb and 232 Th at 190 MeV. Fission product
yields have been measured and an attempt has been
made to reconstruct the charge and mass yield
curves. This is followed by the description of a new
theoretical approach to predict fission fragment
mass yields for both actinides and sub-actinides in
the incident energy range between 10 and 200 MeV.
Temperature dependent fission barriers and prescission
shapes are determined within a
temperature dependent version of the Brosa model.
These quantities combined with the original
random neck rupture model and the existing
nuclear reaction code ALICE-91 provide a new way
of calculating fission fragment and product yields.
The predictive power of this method is tested
against a set of experimental data.
4.6.1. Introduction
The absence of a satisfactory theoretical
description to predict isotope yields as well as the
need for experimental fragment mass and charge
distributions at intermediate energies form the
motivation of this contribution. The work
performed in the framework of the CRP consists of
four separate topics:
(1) Compilation of proton induced fission product
and fission fragment mass distributions from
literature;
(2) Experimental efforts aimed at measuring
proton induced fission product yields at
190 MeV of 232 Th and several sub-actinide
targets;
(3) Development of a new computational method
to predict intermediate energy nucleon
induced fission product mass yields using a
combination of the existing nuclear reaction
code ALICE-91 and the Brosa model
extended with a temperature dependence;
(4) Theoretical predictions of fission fragment
and fission product mass yield curves for all
reactions specified by the CRP benchmark.
M.C. Duijvestijn, A.J. Koning
Nuclear Research and Consultancy Group, Netherlands
Several parts of this research have already
been published in journals and conference
proceedings [4.6.1–4.6.8]. A more detailed
description of the experimental as well as the
theoretical work can be found in Ref. [4.6.9].
4.6.2. Compilation of proton induced
fission product isotope yields
Fission product isotope yield and mass yield
data have been gathered for proton induced
reactions on actinide targets. The search has been
limited to the intermediate energy region (i.e.
proton energies ranging from 15 to 200 MeV). The
data are taken from 14 references. The reaction
specification is found in Table 4.6.1, as are the
incident proton energies, the type of compiled data
(mass yields/isotope yields), the compilation form
(read from figures or tables) and the reference. In
the case of data read from figures, an extra
uncertainty has been added to the published one
because of the inevitable amount of arbitrariness
linked to estimating data from figures. The files
containing the compiled experimental data can be
downloaded from web site: http://ndsalpha.iaea.org/
fycrp/
All data taken from a single reference are
collected in one file. Each entry starts with a title
revealing the necessary information regarding the
target and the incident proton energy, which is
followed by the reference, comments and the data
points. The comments concern the given uncertainties,
whether data are taken from tables or
figures, and a description of the contents of the
columns containing the data points. In case of more
incoming proton energies or target nuclides, entries
are concatenated.
4.6.3. Activation experiment on proton induced
fission of nat W, 197 Au, nat Pb, 208 Pb and 232 Th
at 190 MeV
Several sub-actinide targets and a 232 Th target
have been irradiated with a 190 MeV proton beam
from the AGOR cyclotron at the KVI, Groningen.