Projectile electron loss and capture in MeV/u collisions of U28+ with H2, N2 and Ar
| Autor: | Yong Peng, Vladimir Horvat, Ronald E. Olson, Th. Stöhlker, R. L. Watson, A. N. Perumal |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | Journal of Physics B: Atomic, Molecular and Optical Physics. 37:4539-4550 |
| ISSN: | 1361-6455 0953-4075 |
| Popis: | Electron capture and loss cross sections for U28+ colliding with H2, N2 and Ar were measured at 3.5 and 6.5 MeV/u. These data were used to benchmark n-body calculations using the classical trajectory Monte Carlo method. The n-body calculations include electrons on both nuclear centres and all electron–electron and electron–nuclear interactions between each centre. For the U28+ ion, 36 electrons were incorporated in the calculations (4s24p64d104f145s25p2), while for the H, N and Ar targets all electrons were used except those for the K-shell of Ar, leading to 39-, 45- and 54-body calculations, respectively. Projectile electron loss was predicted for U28+ at energies from 2 to 150 MeV/u. Only for the H-target did the projectile electron loss cross section decrease approximately as E−1. The heavier targets exhibited slower energy dependences, contrary to the E−1 prediction of one-electron theories. Moreover, the collisional interactions are quite strong with an average of 1.64 and 2.88 electrons removed from the U28+ ion at 10 MeV/u in each collision with N and Ar, respectively. These data and calculations were used to assess the vacuum requirements for the SIS-100 synchrotron ring under construction at GSI-Darmstadt. For the residual gases expected to be in the ring, the U28+ lifetime was found to be essentially constant as a function of projectile energy, leading to very stringent vacuum requirements. |
| Databáze: | OpenAIRE |
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