Papers by Author: Yong Nan Zheng

Abstract: The synergistic effect associated with displacement damage, hydrogen and heliumin the China Low Activation Martensitic (CLAM) steel has been investigated using the triple ion beamirradiation. Triple ion beams, an iron beam of 109 MeV degraded by a tantalum foil of 7.45 μm thick, the100 keV hydrogen and 200 keV helium, were injected into the CLAM steel samples simultaneously or sequentially.The radiation damage examinations were carried out by the slow positron Doppler broadening technique. Themeasured S parameters indicate that the radiation damage is different for different irradiationprocedures with same dpa and concentrations of H and He. The sample suffers most severe damage in the simultaneoustriple beam irradiation. The present experimental results support the molecular dynamics simulation result that the H facilitates the He-bubble nucleation and growth.

Abstract: The oxide dispersed strengthened (ODS) ferritic-martensitic steel was irradiated by 100MeV iron ion whose energy was degraded by using a Ta foil of 4 μm thick, 100 keV Hydrogen and 200 keV Helium at 480, 515, 550 and 580 °C. The irradiation fluences were 1×10¹⁶, 1.1×10¹⁵ and 6.8×10¹³/cm², respectively for Fe, H and He. The techniques of positron annihilation lifetime and Doppler broadening of slow positron beam were utilized to examine the produced radiation damage. At 550 °C the maximal positron annihilation lifetime and S parameter of Doppler broadening were observed, implyin g tha t 550 °C is the pea k temperature of swelling. The S parameter and annihilation lifetime of the sample irradiated at 515 °C by the single Fe ion beam were smaller compared to the triple beam irradiation at the same temperature, implying that the triple beam irradiation caused more severe damage than the single beam irradiation.

Abstract: The 9 and 16 MeV proton irradiations of CMOS Image Sensor in the fluence range from 5x108 to 4x1010 cm-2 and 5x109 to 1x1013 cm-2 have been carried out respectively. The color pictures and dark output images are captured, and the average brightness of dark output images is calculated. The anti-irradiation fluence thresholds for 9 and 16 MeV protons are about 4x1010 and 5x1012cm-2, respectively. These can be explained by the change of the concentrations of irradiation-induced electron-hole pairs and vacancies in the various layers of CMOS image sensor calculated by the TRIM simulation program.