@article{oai:repo.qst.go.jp:00047084,
 author = {Fujibuchi, Toshioh and Kodaira, Satoshi and Sawaguchi, Fumiya and Abe, Yasuyuki and Obara, Satoshi and Yamaguchi, Masae and Kawashima, Hajime and Kitamura, Hisashi and Kurano, Mieko and Uchihori, Yukio and Yasuda, Nakahiro and Koguchi, Yasuhiro and Nakajima, Masaru and Kitamura, Nozomi and Sato, Tomoharu and 小平 聡 and 澤口 文哉 and 阿部 泰之 and 小原 哲 and 山口 雅絵 and 川嶋 元 and 北村 尚 and 蔵野 美恵子 and 内堀 幸夫 and 安田 仲宏 and 小口 靖弘},
 journal = {Nuclear Instruments and Methods in Physics Research B},
 month = {Apr},
 note = {We measured the recoil charged particles from secondary neutrons produced by the photonuclear
reaction in a water phantom from a 10-MV photon beam from medical linacs. The absorbed dose and
the dose equivalent were evaluated from the linear energy transfer (LET) spectrum of recoils using the
CR-39 plastic nuclear track detector (PNTD) based on well-established methods in the field of space
radiation dosimetry. The contributions and spatial distributions of these in the phantom on nominal photon
exposures were verified as the secondary neutron dose and neutron dose equivalent. The neutron
dose equivalent normalized to the photon-absorbed dose was 0.261 mSv/100 MU at source to chamber
distance 90 cm. The dose equivalent at the surface gave the highest value, and was attenuated to less than
10% at 5 cm from the surface. The dose contribution of the high LET component of P100 keV/lm
increased with the depth in water, resulting in an increase of the quality factor. The CR-39 PNTD is a
powerful tool that can be used to systematically measure secondary neutron dose distributions in a water
phantom from an in-field to out-of-field high-intensity photon beam.},
 pages = {239--245},
 title = {Measurement of the secondary neutron dose distribution from the LET spectrum of recoils using the CR-39 plastic nuclear track detector in 10 MV X-ray medical radiation fields},
 volume = {349},
 year = {2015}
}