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arXiv · 1110.0570

Effect of an electric field on superfluid helium scintillation produced by alpha-particle sources

T. M. Ito·S. M. Clayton·J. Ramsey·M. Karcz·C. -Y. Liu·J. C. Long·T. G. Reddy·G. M. Seidel
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Abstract

We report a study of the intensity and time dependence of scintillation produced by weak alpha particle sources in superfluid helium in the presence of an electric field (0 - 45 kV/cm) in the temperature range of 0.2 K to 1.1 K at the saturated vapor pressure. Both the prompt and the delayed components of the scintillation exhibit a reduction in intensity with the application of an electric field. The reduction in the intensity of the prompt component is well approximated by a linear dependence on the electric field strength with a reduction of 15% at 45 kV/cm. When analyzed using the Kramers theory of columnar recombination, this electric field dependence leads to the conclusion that roughly 40% of the scintillation results from species formed from atoms originally promoted to excited states and 60% from excimers created by ionization and subsequent recombination with the charges initially having a cylindrical Gaussian distribution about the alpha track of 60 nm radius. The intensity of the delayed component of the scintillation has a stronger dependence on the electric field strength and on temperature. The implications of these data on the mechanisms affecting scintillation in liquid helium are discussed.

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T. M. Ito, S. M. Clayton, J. Ramsey, M. Karcz, C. -Y. Liu, J. C. Long, T. G. Reddy, G. M. Seidel. 2012-04-06. Effect of an electric field on superfluid helium scintillation produced by alpha-particle sources. https://doi.org/10.1103/physreva.85.042718

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