Study of White Neutron Source at CYCIAE-100 for Single Event Effect Irradiation Experiment

Abstract

Neutron-induced single event effects have potential influence on the reliability of electronic devices in aircraft and ground-based nuclear facilities. The white neutron source, generated by heavy metal target bombardment from proton accelerators, is an important tool for studying these effects. Neutron irradiation experiments can provide valuable information such as cross section or threshold for neutron single event effects, allowing prediction of device failure rates in neutron irradiation environments and providing data to support electronic device radiation hardening. Protons from the CYCIAE-100, a 100 MeV proton cyclotron accelerator in China Institute of Atomic Energy, bombard a tungsten target and undergo a scattering reaction, producing white neutrons. Based on nuclear reaction theory and Monte Carlo method, the yield, spectrum, and angular distribution of neutrons produced from the interaction between 100 MeV protons and a tungsten target were simulated. The results show that each 100 MeV proton can produce 0.33 neutrons on average. The neutron energy range is 0-100 MeV, the neutron fluence initially rises and then declines as the energy increases, with the peak occurring near 1 MeV. The angular distribution of the neutrons along the direction of the proton beam is observed to be axisymmetric, and as the emission angle increases, the neutron fluence first decreases and then increases, with the lowest neutron fluence occurring at 90°. The neutron beam in the emission direction of 0° is selected to carry out the single event effect experiment. The energy spectrum of white neutrons is measured by the neutron time-of-flight method based on two liquid scintillation detectors. The neutron energy spectrum is obtained in the range of 3-100 MeV, and when the proton beam is 100 MeV/1 μA, the neutron flux is 3.3×104 cm-2·s-1 at the distance of 15 m from the W target, which meets the requirements of neutron single event effect experiments. Due to the fact that the neutron energy of CYCIAE-100 white neutron source is limited to a maximum of 100 MeV, a direct simulation of the atmospheric neutron energy spectrum is unattainable. Also, disparities exist between the energy spectrum of this neutron source and that of the neutron radiation environment in nuclear industry. Therefore, it is necessary to consider the single event effect response of the device under irradiation with different energies neutron and to explore the development of an accurate approach for experimental evaluation of neutron single event effects.

Keywords

• single event effect
• white neutron source
• neutron energy spectrum