Measurement of neutron-production double-differential cross sections of C, Al, Fe, and Pb by 20, 34, 48, 63, and 78 MeV protons in the most-forward direction

Satoh, Daiki   ; Iwamoto, Yosuke   ; Ogawa, Tatsuhiko   

The Particle and Heavy Ion Transport code System (PHITS) is a general purpose particle transport simulation code developed by the Japan Atomic Energy Agency (JAEA). The PHITS is utilized in various areas including a shielding design of accelerator facilities. Unfortunately, it is known that theoretical models and evaluated nuclear data used in the PHITS cannot reproduce the neutron production in most-forward direction for proton incidences. Hence, the present study aimed to obtain the experimental data of neutron-production double-differential cross sections of C, Al, Fe, and Pb by 20, 34, 48, 63, and 78 MeV protons in most-forward direction for improvement of theoretical models and nuclear data. The experiment has been performed at the ion irradiation facility (TIARA) of the National Institutes for Quantum and Radiological Science and Technology. The proton beams provided by the cyclotron were incident to the target sample. The neutrons produced by nuclear reactions were pass through the collimator in the most-forward direction, and measured with an organic scintillator at the experimental room. The kinetic energy of those neutrons was determined by the time-of-flight method. The obtained results were compared with the results of the theoretical model INCL and the nuclear-data library JENDL-4.0/HE used in the PHITS. It was found that the INCL and JENDL-4.0/HE cannot reproduce the peak structures observed for light nuclei, because they do not consider the nuclear transition between discrete states of nucleus. In addition, the JENDL-4.0/HE agreed with the experimental data of energy-integrated cross section within a factor of 2, but the INCL gave approximately 6 times larger values.