1. First storage of ion beams in the Double Electrostatic Ion-Ring Experiment - DESIREE
- Author
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Schmidt, H. T., Thomas, R. D., Gatchell, M., Rosén, S., Reinhed, P., Löfgren, P., Brännholm, L., Blom, M., Björkhage, M., Bäckström, E., Alexander, J. D., Leontein, S., Hanstorp, D., Zettergren, H., Liljeby, L., Källberg, A., Simonsson, A., Hellberg, F., Mannervik, S., Larsson, M., Geppert, W. D., Rensfelt, K. G., Danared, H., Paál, A., Masuda, M., Halldén, P., Andler, G., Stockett, M. H., Chen, T., Källersjö, G., Weimer, J., Hansen, K., Hartman, H., and Cederquist, H.
- Subjects
Physics - Accelerator Physics ,Physics - Atomic Physics ,Physics - Instrumentation and Detectors - Abstract
We report on the first storage of ion beams in the Double ElectroStatic Ion Ring ExpEriment; DESIREE, at Stockholm University. We have produced beams of atomic carbon anions and small carbon anion molecules (C$_n^-$, $n=1,2,3,4$) in a sputter ion source. The ion beams were accelerated to 10 keV kinetic energy and stored in an electrostatic ion storage ring enclosed in a vacuum chamber at 13 K. For 10 keV C$_2^-$ molecular anions we measure the residual-gas limited beam storage lifetime to be 448 s $\pm$ 18 s with two independent detector systems. Using the measured storage lifetimes we estimate that the residual gas pressure is in the 10$^{-14}$ mbar range. When high current ion beams are injected, the number of stored particles does not follow a single exponential decay law as would be expected for stored particles lost solely due to electron detachment in collision with the residual-gas. Instead, we observe a faster initial decay rate, which we ascribe to the effect of the space charge of the ion beam on the storage capacity. %The latter effect becomes insignificant after longer storage times of typically 100-150 seconds and we then observe a constant decay rate due to residual-gas collisions.
- Published
- 2018
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