Program - Brookhaven National Laboratory

improve the models and reach the accuracy required for a reference simulation code for hadrontherapy, a
second experiment has been performed on thin targets on May 2011 at GANIL. The experimental set-up
was made of five three stages δE-E telescopes, each composed of two Si detectors and one CsI scintillator
mounted on rotating stages to cover angles from 4 ◦ to 45 ◦ . The energy calibration of the detector and the
identification of the fragments have been achieved. The double differential cross sections δ 2 σ/(δEδΩ) have
been obtained for all fragment isotopes from p to 12 C for nuclear reactions of 12 C with H, C. Al, O and
nat Ti. Simulations are under completion to evaluate the systematic uncertainties (first estimations lead to
an accuracy of 10% for Z>2 fragments and up to 20-30% for protons at forward angles). The cross sections
increase with the mass of the target. The results also show a more forward-focused angular distributions
for heavier fragments and a predominance of Z=2 fragments at forward angles (< 10 ◦ ), compatible with the
three alpha structure of the 12 C. The energy distributions of the fragments at forward angles are peaked
close to the beam energy showing an emission dominated by the quasiprojectile. The angular and energy
cross sections obtained with a thin PMMA target have been reproduced with a 10% accuracy thanks to
the elemental cross sections obtained on C, H and O targets. The experimental setup and the results for
the different targets will be presented.
Corresponding author: Labalme Marc
[1] B. Braunn et al., ”Nuclear reaction measurements of 95MeV/u 12 C interactions on PMMA for hadrontherapy”,
Nucl. Inst. Meth. B 269 (2011), 2676.
HB 5 5:00 PM
Measurement of Capture Gamma Rays from the Tc-99 Neutron Resonances at the
J-PARC/ANNRI
Koichi Kino, Fujio Hiraga, Takashi Kamiyama, Yoshiaki Kiyanagi
Hokkaido University
Hideo Harada, Kaoru Y. Hara, Kentaro Hirose, Atsushi Kimura, Fumito Kitatani,
Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency
Masayuki Igashira, Tatsuya Katabuchi, Motoharu Mizumoto
Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology
Jun-ichi Hori
Research Reactor Institute, Kyoto University
Tc-99 is one of the important nuclei among long-lived fission products contained in nuclear waste. To reduce
its radioactive toxicity using a fast reactor or an accelerator driven system, accurate neutron-capture data
are needed. Therefore, experiments of neutron-capture and total reactions have been performed, and
resonance parameters have been derived by fitting the theoretical function on the spectra as a function
of the neutron energy. On the other hand, radiative width, which is one of the resonance parameters,
can be obtained by analyzing the capture gamma rays from the neutron resonances and calculating their
intensities. We bombarded the pulsed neutron beam on a Tc-99 sample at the Accurate Neutron-Nucleus
Reaction measurement Instrument (ANNRI) at the J-PARC and observed capture gamma rays by the 4-pi
Ge spectrometer. The neutron energy was obtained by measuring the neutron flight time. The primary
gamma-ray transition pattern from the 1st resonance was found to be similar to that from the capture
reaction of thermal neutrons. On the other hand, transition patterns from the higher energy resonances
were completely different. In this presentation, capture gamma rays from neutron resonances are reported
and discussed. This work was supported by JSPS KAKENHI Grant Number 22226016.
HB 6 5:15 PM
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