JAEA-Conf 2011-002 - 日本原子力研究開発機構

Shusuke HIRAYAMA 1 , Yukinobu WATANABE 1 , Yuuki NAITOU 1 , Pernilla ANDERSSON 2 ,
Riccardo BEVILACQUA 2 , Cecilia GUSTAVSSON 2 , Anders HJALMARSSON 3 ,
Michael ÖSTERLUND 2 , Stephan POMP 2 , Alexander PROKOFIEV 3 , Vasily SIMUTKIN 2 ,
Henrik SJÖSTRAND 2 , Milan TESINSKY 4 , Udomrat TIPPAWAN 5 and Satoshi KUNIEDA 6
1 Department of Advanced Energy Engineering Science, Kyushu University,
Kasuga, Fukuoka 816-8580, Japan
2 Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
3 The Svedberg Laboratory, Uppsala University, Box 533, SE-751 21 Uppsala, Sweden
4 Department of Nuclear and Reactor Physics, Royal Institute of Technology, 106 91 Stockholm, Sweden
5 Plasma and Beam Physics Research Facility, P.O.Box 217, 50200, Thailand
6 Nuclear Data Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
Email: hirayama@aees.kyushu-u.ac.jp
We have measured double differential cross sections of protons and alphas produced from silicon
induced by 175 MeV quasi mono-energetic neutrons using the Medley setup at the TSL neutron beam
facility in Uppsala University. The measured data are analyzed using the exciton model incorporating the
Iwamoto-Harada-Sato (IHS) coalescence model, with particular attention to the energy dependence of the
pick-up radius parameter ΔR in the IHS model.
Recently, single event effects (SEEs) caused by cosmic-ray neutrons in logic and memory circuits
have been recognized as a key reliability concern for modern microelectronic devices. When electronic
memory circuits are exposed to neutron radiation, secondary ions are produced by nuclear interaction with
atomic nuclei in materials. The released charge can cause a flip of the memory information in a bit, which
is called a single-event upset (SEU). Recent work has elucidated that the contribution from secondary light
ions (i.e., p, d, t, 3 He and α) to SEU becomes increasingly important as the size of microelectronic devices
becomes smaller and smaller [1,2]. Therefore, reliable nuclear data for neutron-induced light ion production
over a wide incident energy range are strongly required to simulate accurately the SEEs including SEU.
However, there is no measurement for silicon target in the energy range of more than 100 MeV.
In the present work, we have measured double-differential production cross section of p, d, t, 3 He,
and from silicon bombarded by 175 MeV quasi mono-energetic neutrons. The experimental data are
compared with the exciton model calculations in which we use the surface coalescence model proposed by
Iwamoto, Harada, and Sato [3]. The results of proton and alpha production are reported in this paper.
JAEA-Conf 2011-002
Details of the experimental set up have been reported in Refs.[4,5]. A thin silicon target placed in
the Medley chamber was irradiated by quasi mono-energetic neutrons generated by the 7 Li(p,n) 7 Be reaction.
The target consisted of double silicon wafer discs and its size was 0.96mm thick and 25 mm in diameter.
Energy and angular distributions of light-ions produced from the silicon target were measured with the
Medley setup. The Medley setup was composed of eight telescopes placed at angles from 20° to 160° in
steps of 20°. Each telescope consisted of two silicon surface barrier detectors (50~60 μm and 1000 μm) as
the ΔE detector and a CsI(Tl) detector as the E detector. Moreover, the incident neutron spectrum was
measured using the same setup with both 5mm-thick polyethylene (CH2) target 25mm in diameter and