20 K cryo-transfer tem observation of nascent displacement cascade damages in low temperature D-T neutron-irradiated metals at RTNS-II

• Published in: Journal of nuclear materials 1988-07, Vol.155-157, p.1181-1187
• Main Authors: Shimomura, Y., Guinan, M.W., Fukushima, H., Hahn, P.A., Kiritani, M.
• Format: Article
• Language: English
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/0022-3115(88)90492-8

TEM specimens of a variety of metals were irradiated below 16 K with D-T neutrons at RTNS-II and cryotransferred below 24 K to a JEM-200CX electron microscope. After the observation of nascent defects at temperatures below 24 K, the specimen temperature was raised in the electron microscope to examine changes in the defects. Defects observed at low temperature generally do not change much for heat treatment below stage III, but major structure changes are caused by 200 keV electron illumination. In electron-illuminated areas of gold, some defects disappear during annealing to 200 K and bubbles appear during 175 K observation after 200 K anneal, in areas where no defects were observed previously. There is a similarity of defect evolution in electron-illuminated areas in a number of metals. In nascent displacement cascades in most metals, both interstitials and vacancies form small aggregates of sub-microscope size; some observable interstitial loops are also formed.