JAEA-Conf 2011-002 - 日本原子力研究開発機構

JAEA-Conf 2011-002
Masayuki HAGIWARA 1) , Toshiya SANAMI 1) , Yosuke IWAMOTO 2) , Norihiro
MATSUDA 2) , Yukio SAKAMOTO 2) , Yoshihiro NAKANE 2) ,
Hiroshi NAKASHIMA 2) , Kazuyoshi MASUMOTO 1) , Yoshitomo UWAMINO 3)
1)
High Energy Accelerator Research Organization, KEK, Oho 1-1, Tsukuba-shi,
Ibaraki-ken 305-0801
2)
Japan Atomic Energy Agency, Shirakata-shirane 2-4, Tokai-mura, Naka-gun,
Ibaraki-ken 319-1184
3)
RIKEN, Hirosawa 2-1, Wako-shi, Saitama-ken 351-0198
e-mail: hagi@post.kek.jp
Differential thick target yields (TTYs) of neutrons and -rays induced by 18 MeV
protons have been measured at nine laboratory angles between 0- and 150-degrees using
various targets ( 9 Be, nat C, 27 Al, nat Cu, 181 Ta and 18 H2O), in order to assess the nuclear data
libraries and calculation codes for the proton-induced reaction at low energies. 5.08 cm
diameter × 5.08 cm long NE213 scintillators were employed with pulse-shape-discrimination
technique for separation of neutron and -ray events. The neutron and -ray events were
analyzed by a time-of-flight (TOF) technique and an unfolding technique, respectively. The
measured TTYs were compared with calculation results on the basis of the several nuclear
data libraries and physical models.
Nuclear data on proton-induced neutron and -ray production in the energy range
from 10 to 20 MeV is important to execute the shielding design and to estimate activation of
low-energy accelerator facilities such as medical-purpose accelerators for production of
radiopharmaceuticals in positron emission tomography (PET) and a neutron source of boron
neutron capture therapy (BNCT). The energy and angular distribution of neutrons produced
though interactions between incident protons and accelerator components should be estimated
for radiation safety as well as clearance of the facility. However, the experimental data on the
energy and angular distribution for production of neutrons as well as -rays are very scarce
especially for proton energies from 10 to 20 MeV 1) . So far, estimation of shielding and
activation of such facilities was performed using nuclear data libraries and calculation codes
such as PHITS 2) , LA150 and MCNPX 3) . The accuracy of the codes and nuclear data library