Laboratory Simulation of the Positron-Dust Interaction and its Implication for Interstellar Dark Clouds

0573218 - ÚFP 2024 RIV GB eng J - Journal Article
Wild, J. - Čížek, J. - Nouzák, L. - Pavlů, J. - Šafránková, J. - Němeček, Z. - Vaverka, J. - Nosek, D. - Burian, Tomáš - Wildová, A. - Broulím, J.
Laboratory Simulation of the Positron-Dust Interaction and its Implication for Interstellar Dark Clouds.
Astrophysical Journal. Roč. 942, č. 1 (2023), č. článku 42. ISSN 0004-637X. E-ISSN 1538-4357
Institutional support: RVO:61389021
Keywords : positron-dust interaction * interstellar dark clouds * radioisotope
OECD category: Fluids and plasma physics (including surface physics)
Impact factor: 4.9, year: 2022
Method of publishing: Open access
https://iopscience.iop.org/article/10.3847/1538-4357/aca01c

We report the first laboratory experiment dealing with the interaction of a cosmic dust simulant with positrons emitted from a 22Na radioisotope. Measurements of a charge of micrometer SiO2 dust grains with an accuracy of one elementary charge e revealed +1 e steps due to positron annihilation inside the grain. The observed average rate of these charging events agrees well with prediction of a model based on the continuous slowing down approximation of energetic of positrons inside the grain. Less frequent charge steps larger than +1 e were attributed to emission of secondary electrons during positron slowing down. The determined coefficient of secondary electron emission is approximately inversely proportional to the grain radius. The experimental results led us to the formulation of a possible scenario of interstellar dark clouds charging.
Permanent Link: https://hdl.handle.net/11104/0343733