Program - Brookhaven National Laboratory

There has been considerable effort in recent years in the investigation of neutrino physics. For example,
understanding neutrino oscillations is an important aspect of fundamental physics. Controlled sources
of the large number of neutrinos needed to be able to detect them are nuclear reactors, and, in fact,
acquiring neutrino spectra is rapidly becoming an important tool for reactor monitoring [1]. A complete
understanding of the spectra is essential to be able to correctly interpret results in any case. A neutrino
spectrum for a single beta decay may be obtained through an inversion of the beta decay spectrum. The
total neutrino spectrum is obtained by following the decay branches of the fission products. The nuclear
decay sub-libraries were recently updated at the NNDC and among the over 3800 datasets are around
700 fission products including isomers. Included in the update are the latest Q values (for which the
neutrino spectra is sensitive), the latest experimental data from ENSDF, and in some cases, TAGS (total
absorption) data . Based on the sub-libraries, the decay network following fission was followed to develop
full neutrino spectra in several important cases. Presented are results for 235 U, 238 U, and 239 Pu. These
results are compared against recent experimental data from the reactors at Daya Bay [2]. Key contributors
to the spectra were identified, and sensitivity studies were carried out.
[1] D.Lhuiller, Nuclear Physics B. (Proc. Supp.) 188 (2009) 112-114 [2] F.P. An, et al. arXiv:1203.1669v1
[hep-ex] 8 Mar 2012
FD 4 11:40 AM
Reactor and Antineutrino Spectrum Calculations for the Double Chooz First Phase Results
Anthony Onillon, on behalf of the Double Chooz collaboration
Laboratoire Subatech, FRANCE
The Double Chooz experiment is designed to measure the θ13 mixing angle through antineutrinos disappearance.
In this view, two identical liquid detectors located at two different baselines of the two 4.25MW
Pressurized Water Reactor (PWR) cores of the Chooz power plant in the French Ardennes will be installed.
The value of θ13 can be investigated by searching for a disappearance of electron antineutrinos
in the far detector with respect to the antineutrinos measured in the near detector. The Double Chooz
experiment has started taking data from April 2011. From the results of this first experimental phase,
we have obtained an indication for a reactor electron antineutrino disappearance consistent with neutrino
oscillations. During this, only the far detector is operational. A full core simulation of the two PWRs with
a follow-up of the core operating parameters has thus been developed with the MURE code (MCNP Utility
for Reactor Evolution) to compute the reactor fission rates. The reactor antineutrino flux is then deduced
by coupling the fission rates with the recently computed reference antineutrino spectra by P. Huber and
using the normalisation of the Bugey4 antineutrino flux measurement after correction for differences in
the core composition. We propose at this conference, to present the latest results of the Double Chooz
experiment and detail the ingredients that led to the antineutrino spectrum prediction that was compared
with the experimental data.
Session FE Benchmark and Testing
Tuesday March 5, 2013
Room: Central Park West at 10:30 AM
FE 1 10:30 AM
Integral Data Testing of ENDF/B-VII.1 Files - Success Stories and Need to Improve Stories
A.C. Kahler, R.E. MacFarlane, M.B. Chadwick
Los Alamos National Laboratory
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