Study of Positronium in Low-k Dielectric Films by Means of 2D-Angular Correlation Experiments at a High-Intensity Slow-Positron Beam.

Gessmann, T. ; Petkov, M. P. ; Weber, M. H. ; Lynn, K. G. ; Rodbell, K. P. ; Asoka-Kumar, P. ; Stoeffl, W. ; Howell, R. H.

Technical Information Center Oak Ridge Tennessee

关键词: Annihilation radiation;    Slow positron beam;    Dielectric films;    Angular correlation;    Two dimensional;   

RP-ID  :  DE200515013214

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

Depth-resolved measurements of the two-dimensional angular correlation of annihilation radiation (2D-ACAR) were performed at the high-intensity slow-positron beam of Lawrence Livermore National Laboratory. We studied the formation of positronium in thin films of methylsilsesquioxane (MSSQ) spin-on glass containing open-volume defects in the size of voids. Samples with different average void sizes were investigated and positronium formation could be found in all cases. The width of the angular correlation related to the annihilation of parapositronium increased with the void size indicating the annihilation of non-thermalized parapositronium.