Abstract:
The partly stripped ions get loss in storage ring when the charge state changes through collision ionization by residual gas and capturing electrons from electron beam. It was found in the first electron cooling commissioning of
12C
3+ beam at HIRFL-CSRe that the lifetime of 122 MeV/u
12C
3+ beam is only 6.6 s shorter than expected, and the electron cooling effect is unobvious. The lifetime of
12C
3+ at CSRe and its electron cooling time were calculated in this paper. The result shows that the vacuum pressure at the order of 10
-8 Pa causes severe
12C
3+ beam loss at CSRe. The beam loss due to recombination and cooling effect is unapparent in comparison with the one by collision ionization. The calculation explains the accidental fast beam loss in the first electron cooling commissioning of
12C
3+ beam at CSRe.
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