Light Ion Accelerator High Voltage Electron Microscope Facility for CTR Radiation Damage Studies

A 200kV light ion accelerator has been linked to the specimen chamber of a 500kV transmission electron microscope to simulate some of the radiation environment conditions expected for first wall material in a fusion reactor. Both the electrons of the HVEM and the ions from the attached accelerator impinge simultaneously on the specimen and cause their respective amounts of displacement damage. This Simultaneous Accelerator Microscope Irradiation (SAMI) facility is presently being used to conduct two types of radiation damage studies on candidate first wall material, austenitic stainless steel. One study involves in-situ tensile deformation of ribbon shaped samples helium irradiated in order to elucidate mechanisms of helium embrittlement. Another study concerns in-situ observations of the development of microstructure under helium ion bombardment. Both types of experiments are performed during continuous observation in the HVEM and allow recording by a video tape system of the dynamic processes.