Program - Brookhaven National Laboratory

CD 4 2:40 PM
Development of a System for Measuring the Shape of β Spectra Using a Semiconductor Si
Detector
C. Bisch, X. Mougeot, M.-M. Be
CEA, LIST, LNHB, Gif-Sur-Yvette, F-91191, France
The study of the shape of β spectra is experiencing a resurgence of interest having been little studied since
the late 1970s. Precise knowledge of the shape of energy spectra, coupled with well established uncertainties,
are sought by users from the nuclear power industry (decay heat calculations), medical care sector (dose
calculations) or ionizing radiation metrology (reduction of uncertainties in activity measurements using the
liquid scintillation technique). As the primary laboratory for measurement of radioactivity in France, the
Laboratoire National Henri Becquerel (LNHB) requires a computer code to meet the demands of users,
which should be validated against experiment. Hence, an operational device using a semiconductor Si
detector (easy to implement, linear response function, good energy resolution) has been developed in order
to measure spectra shape and to quantify the uncertainties. The main difficulties arise because the spectra
may be distorted by the detection system (detector efficiency, non-linearity of electronics) and physical
phenomena (thickness and homogeneity of the source, detector dead zones, angle of incidence, scattering
and backscattering, bremsstrahlung). The entire setup has been designed to attempt a measurement of the
true spectral shape, by limiting sources of deformation (ultra-thin source, ultra vacuum, detector cooled to
liquid nitrogen temperature, low scattering materials, limitation of microphonics). Finally, our attention
is focused particulary on the two main components of the experimental device, i.e. the detection chamber
and source holder. These have been studied by Monte-Carlo calculations (GEANT4) to determine the
geometry and materials least likely to scatter electrons. This paper describes the experimental setup and
presents the first results.
Session CE Integral Experiments
Monday March 4, 2013
Room: Central Park West at 1:30 PM
CE 1 1:30 PM
Integral Benchmark Data for Nuclear Data Testing Through the Icsbep and IRPhEP
J. Blair Briggs and John D. Bess
Idaho National Laboratory
Jim Gulliford
OECD Nuclear Energy Agency
The status of the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and International
Reactor Physics Experiment Evaluation Project (IRPhEP) was last discussed directly with the
nuclear data community at ND-2007. Since ND 2007, integral benchmark data that are available for nuclear
data testing has increased significantly. The contents of the International Handbook of Evaluated
Criticality Safety Benchmark Experiments have increased from 442 evaluations (38,000 pages) containing
benchmark specifications for 3955 critical, subcritical, or k-infinity configurations to 550 evaluations (over
65,000 pages) containing benchmark specifications for over 4700 critical, subcritical, or k-infinity configurations.
The number of criticality-alarm-placement / shielding evaluations has increased from 23 to 24 and
fundamental physics evaluations from 20 to 24 in the 2012 edition of the ICSBEP Handbook. Approximately
15 new evaluations and 150 additional configurations are expected to be added to the 2013 edition of
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