Program - Brookhaven National Laboratory

fuel cycle impose tight requirements on nuclear data for accurate predictions of their operation and safety
characteristics. Among the identified needs established by sensitivity studies, neutron inelastic scattering on
the main structural materials and actinides and some (n,xn) cross sections for actinides feature prominently.
Neutron inelastic scattering measurements using the (n,n’g)-technique are carried out at two measurement
setups at the GELINA neutron time-of-flight facility of IRMM. The GAINS setup has 12 high purity
coaxial germanium detectors of 8 cm diameter and length and is placed at 200 m from the neutron source
for a 1 keV neutron energy resolution at 1 MeV. It is readily applied for elemental and enriched samples
of stable isotopes for which sizeable samples are easily obtained. The GRAPHEME setup, established by
CNRS/IN2P3/IPHC has 4 high purity planar detectors and is placed at 30 m from the neutron source for
optimal intensity in studies of actinide samples. The latter samples need to be thin (0.2 mm) to minimize
the self-absorption of the low-energy gamma-rays characteristic for the decay of the low-lying levels in
actinide targets. Recent progress of the measurements will be shown for 23 Na, 63,65 Cu, Mo, Zr, 76 Ge,
232 Th and 235,238 U. Modeling and evaluation of the data is essential for advancing the use of these data
in applications. This requires a close collaboration with the theoretical and evaluation communities thus
enabling our results to be compared with state-of-the-art model calculations. Studies for Na, Mo, Zr, and
238 U are co-sponsored by the European Commission’s FP7 programme via the ANDES project. The work
for 76 Ge supports the GERDA and similar experiments searching for evidence of neutrinoless double-beta
decay.
PR 86
Light-Ion Production in 175 MeV Neutron-Induced Reactions on Oxygen
U. Tippawan, T. Vilaithong, Plasma and Beam Physics Research Facility, Chiang Mai University, P.O.
Box 217, 50200 Chiang Mai, Thailand. S. Pomp, P. Andersson, R. Bevilacqua, J. Blomgren,
C.Gustavsson, L. Nilsson, M. Osterlund, V. Simutkin, H. Sjöstrand, Division of Applied Nuclear Physics,
Department of Physics and Astronomy, Uppsala University, Box 525, SE-751 20 Uppsala, Sweden. M.
Hayashi, S. Hirayama, Y. Watanabe, Department of Advanced Energy Engineering Science, Kyushu
University, Japan. A. Hjalmarsson, A. Prokofiev, The Svedberg Laboratory, Uppsala University, Box 533,
SE-751 21 Uppsala, Sweden. M. Tesinsky, Department of Nuclear and Reactor Physics, Royal Institute of
Technology, 106 91 Stockholm, Sweden.
Over the past years several applications involving high-energy neutrons (E>20 MeV) have been developed
or are under consideration, e.g., radiation treatment of cancer, neutron dosimetry at commercial aircraft
altitudes, soft-error effects in computer memories, accelerator-driven transmutation of nuclear waste and
energy production. Data on light-ion production in light nuclei such as carbon, nitrogen and oxygen are
particularly important in calculations of dose distributions in human tissue for radiation therapy at neutron
beams, and for dosimetry of high energy neutrons produced by high-energy cosmic radiation interacting
with nuclei (nitrogen and oxygen) in the atmosphere. When studying neutron dose effects, it is especially
important to consider carbon and oxygen, since they are, by weight, the most abundant elements in human
tissue. Such data have been measured with the MEDLEY setup based at The Svedberg Laboratory
(TSL), Uppsala, Sweden. It has been used to measure differential cross sections for elastic nd scattering
and double-differential cross sections for the (n,xp), (n,xd), (n,xt), (n,x 3 He), and (n,xα) reactions from
C, O, Si, Ca, Fe, Pb, and U around 96 MeV [1]. In the new Uppsala neutron beam facility the available
energy range of quasi mono-energetic neutron beams is extended up to 175 MeV. The detector setup used
in MEDLEY [2] consists of eight so-called telescopes mounted at different angles inside an evacuated reaction
chamber. Each of the telescopes consists of two fully depleted ∆E silicon surface barrier detectors
(SSBD) and a CsI(Tl) crystal. To allow for measurements at this higher neutron energy some changes in
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