Monte Carlo simulation of photon emission below a few hundred kiloelectronvolts for beam monitoring in carbon ion therapy.
The purpose of this study is to determine whether the main component of the low-energy (63-68 keV) particles emitted perpendicularly to the12C beam from the12C-irradiated region in a water phantom is secondary electron bremsstrahlung (SEB). Monte Carlo simulations of a12C-beam (290 MeV/u) irradiated on a water phantom were performed. A detector was placed beside the water phantom with a lead collimator between the phantom and the detector. To move the Bragg-peak position, a binary filter was placed in an upper stream of the phantom. The energy distributions of the particles incident on the detector and those deposited in the detector were analyzed. The simulation was also performed with suppressed delta-ray and/or bremsstrahlung generation to identify the SEB components. It was found that the particles incident on the detector were predominantly photons and neutrons. The yields of the photons and energy deposition decreased with the suppression of SEB generation. It is concluded that one of the predominant components of the yields in the regions shallower than the Bragg-peak position is due to SEB generation, and these components become significantly smaller in regions deeper than the Bragg-peak position.
Takasaki Advanced Radiation Research Institute, Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki-machi, Takasaki, Gunma, Japan.
Mitsutaka
0000000234124066
M
Yamaguchi
Takasaki Advanced Radiation Research Institute, Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki-machi, Takasaki, Gunma, Japan.
Yuto
Y
Nagao
Takasaki Advanced Radiation Research Institute, Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki-machi, Takasaki, Gunma, Japan.
Takahiro
T
Satoh
Fukushima Prefectural Centre for Environmental Creation, 10-2 Fukasaku, Miharu-machi, Tamura-gun, Fukushima, Japan.
Hiroyuki
H
Sugai
Gunma University Heavy Ion Medical Center, Gunma University, 3-39-22 Showa-machi, Maebashi, Gunma, Japan.
Makoto
M
Sakai
Takasaki Advanced Radiation Research Institute, Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki-machi, Takasaki, Gunma, Japan.
Kazuo
K
Arakawa
Takasaki Advanced Radiation Research Institute, Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki-machi, Takasaki, Gunma, Japan.
Naoki
N
Kawachi