Program - Brookhaven National Laboratory

M.R. Gilbert, L.W. Packer, S. Lilley
EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxfordshire, OX14 3DB, UK
The 14 MeV neutrons generated in the plasma of future fusion reactors will initiate nuclear reactions in the
materials of the surrounding first wall and vacuum-vessel components, leading to compositional changes in
the constituent materials. Accurate predictions of this transmutation and the resulting activation are vital
to inform the engineering design and material choice for fusion reactors. Neutron transport simulations
combined with inventory calculations, with codes such as MCNP and FISPACT, respectively, can produce
the necessary quantitative predictions, but the reliability of these is largely dependent on the quality of
the nuclear reaction cross section data. In many (most!) cases, the data for a particular reaction, in a
database such as the European Activation File (EAF), is either largely or entirely based on theoretical
calculations because little or no experimental data exists. In an effort to further improve the quality of
data for fusion relevant materials, CCFE has undertaken a series of neutron irradiation experiments at
the ASP experimental facility, which is hosted by AWE at their Aldermaston site in the UK. Here, a
deuteron beam is directed onto a tritium target, leading to the DT fusion reaction and the production
of 14 MeV neutrons. The γ-spectra emitted from sample-foils irradiated in this environment have been
measured. To date around 160 irradiations have been performed, producing more than 8500 individual
γ-spectra. The characteristic peaks from a single energy spectrum resulting from a foil experiment can
be analysed by hand using proprietary software packages, but the processing of the complete data set has
necessitated the creation of a set of automated processing tools. Apart from the ability to handle all of
the data in consistent and well-understood manner, which may not always be the case with commercial
software, the automated approach also has the advantage of allowing the data to be rapidly and easily
reprocessed, as is often required as the quantification of the experimental conditions is refined. In this
paper we discuss the various methods used to process and analyze the data, including peak separation,
flux measurement using reference peaks, and decay-corrected activity and half-life measurement via data
fitting. Additionally, we illustrate, with examples, how the automated processing gives a fuller picture of
the variation in peak-count rate for a particular experiment, sometimes revealing extra information that
may not have been evident in the analysis of a single spectrum. This work was funded by the RCUK Energy
Programme under grant EP/I501045 and the European Communities under the contract of Association
between EURATOM and CCFE. The views and opinions expressed herein do not necessarily reflect those
of the European Commission.
Session DD Nuclear Structure and Decay
Monday March 4, 2013
Room: Empire West at 3:30 PM
DD 1 3:30 PM
Total Absorption Study of Beta Decays Relevant for Nuclear Applications and Nuclear
Structure
A. Algora, for the Valencia-Nantes-Surrey-Jyväskylä-Debrecen-Gatchina-Madrid collaboration
IFIC (CSIC-Univ. of Valencia)
In this contribution we will present an overview of our recent studies of the beta decay of nuclei relevant
for nuclear applications, as a continuation of our line of research related to nuclear data [1]. The measurements
are performed using the best available technique to detect the beta feeding probability, the total
absorption technique (TAS). In our studies we have combined the TAS technique with the use of a Penning
Trap (JYFLTRAP, Univ. of Jyväskylä) as a high resolution isobaric separator in order to guarantee high
66