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Center for Nonlinear Studies |
Accurate modeling of the transport of electrons and positrons through dense media is essential for understanding and improving such applications as plasma medicine, liquid particle detectors and PET scans. In contrast to the modeling of transport through dilute gases, liquids present challenges due to the quantum nature of the light particle, i.e. the electron or positron. This can be seen in the effects of screening, multiple scattering and solvation. I will present our formalism for approaching this behavior using ab initio techniques as much as possible. We have successfully applied the formalism to transport in the noble gases, exploring electrons in liquid argon and xenon and positrons in helium in both its liquid and dense gas phases. Our predictions agree with experimental measurements where they are available, and allows us to predict a wider range of situations. I will also discuss recent related work, exploring the propagation of positrons through plasmas. This can be as a diagnostic, both in lab-based plasmas and in gamma-ray observations from the Galaxy. In both cases, there are some useful properties that can be identified from the annihilation signals.
Host: Xianzhu Tang / Nathan Garland