Experiments with a High-Density Positronium Gas
| Autor: | Norikazu Nishiyama, Hiroyuki Tanaka, David Cassidy, J. B. Snyder, R. G. Greaves, Allen P. Mills, T. Maruo, S. H. M. Deng |
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| Rok vydání: | 2005 |
| Předmět: | |
| Zdroj: | Physical Review Letters. 95 |
| ISSN: | 1079-7114 0031-9007 |
| DOI: | 10.1103/physrevlett.95.195006 |
| Popis: | We have created a high-density gas of interacting positronium (Ps) atoms by irradiating a thin film of nanoporous silica with intense positron bursts and measured the Ps lifetime using a new single-shot technique. When the positrons were compressed to $3.3\ifmmode\times\else\texttimes\fi{}{10}^{10}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$, the apparent intensity of the orthopositronium lifetime component was found to decrease by 33%. We believe this is due to a combination of spin exchange quenching and ${\mathrm{Ps}}_{2}$ molecule formation associated with colliding pairs of oppositely polarized triplet positronium atoms. Our data imply an effective cross section for this process of $2.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$. |
| Databáze: | OpenAIRE |
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