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arXiv · 2511.02889

A model for positron annihilation in multi-layer systems by solving the diffusion equation using different positron affinities

Lucian Mathes·Michael Göldl·Michael Leitner·Bettina Kohlhaas·Maximilian Suhr·Vassily Vadimovitch Burwitz·Armin Manhard·Christoph Hugenschmidt
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Abstract

We present a method for solving the positron diffusion equation in multi-layer systems. Our approach incorporates material-specific implantation profiles, diffusion parameters, and positron affinities. It utilizes a Markov chain approach to model annihilation probabilities and provides fitting capabilities for experimental S (lineshape) parameter data. We have implemented this algorithm in Python and made it available for free under the name LIMPID. To demonstrate its performance, we analyze depth-resolved Doppler-Broadening Spectroscopy measurements of a Cu layer on a Si substrate, achieving excellent agreement with the experimental profiles. The LIMPID tool enhances the reproducibility and comparability of positron defect characterization measurements across different research groups.

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Lucian Mathes, Michael Göldl, Michael Leitner, Bettina Kohlhaas, Maximilian Suhr, Vassily Vadimovitch Burwitz, Armin Manhard, Christoph Hugenschmidt. 2025-11-04. A model for positron annihilation in multi-layer systems by solving the diffusion equation using different positron affinities. https://arxiv.org/abs/2511.02889

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