Measurement of carbon ion incident neutron production double differential cross sections for carbon target

Shigyo, Nobuhiro*; Uozumi, Yusuke*; Kajimoto, Tsuyoshi*; Moriguchi, Daisuke*; Ueyama, Masahiko*; Yoshioka, Masakatsu*; Koba, Yusuke*; Nakamura, Yasuhiro*; Satoh, Daiki   ; Sanami, Toshiya*; Takada, Masashi*; Matsufuji, Naruhiro*

Radiation dose by neutrons produced by proton and heavy ion induced nuclear reactions around tumor is essential for dose assessment in proton and heavy ion radiotherapies. Double differential cross section (DDX) of neutron production is one of important physical quantities for dose estimation by radiation transport codes. Some experimental data of neutron production DDXs have been reported above 5 MeV of neutron energy for heavy ion incident reactions. Neutron production DDX for carbon ion incidence on carbon target was measured at the Heavy Ion Medical Accelerator in Chiba (HIMAC) including low neutron energy region for validation of radiation transport codes. Incident carbon energy was 290 MeV/u. NE213 liquid organic scintillators were deployed as neutron detectors and placed at 15, 30 45, 60, 75 and 90. Neutron energies were determined by the time-of-flight methods. Neutron detection efficiency was calculated by the SCINFUL-QMD code. The obtained minimum neutron energy was about 2.8 MeV. The experimental data of neutron production DDX was compared with that by one of radiation transport codes, PHITS.