Kinematically complete experimental study of Compton scattering at helium atoms near the ionization threshold
Abstract
Compton scattering is one of the fundamental interaction processes of light with matter. Already upon its discovery [1] it was described as a billiard-type collision of a photon kicking a quasi-free electron. With decreasing photon energy, the maximum possible momentum transfer becomes so small that the corresponding energy falls below the binding energy of the electron. Then ionization by Compton scattering becomes an intriguing quantum phenomenon. Here we report a kinematically complete experiment on Compton scattering at helium atoms below that threshold. We determine the momentum correlations of the electron, the recoiling ion, and the scattered photon in a coincidence experiment finding that electrons are not only emitted in the direction of the momentum transfer, but that there is a second peak of ejection to the backward direction. This finding links Compton scattering to processes as ionization by ultrashort optical pulses [2], electron impact ionization [3,4], ion impact ionization [5,6], and neutron scattering [7] where similar momentum patterns occur.
Keywords
Cite
@article{arxiv.1911.04780,
title = {Kinematically complete experimental study of Compton scattering at helium atoms near the ionization threshold},
author = {Max Kircher and Florian Trinter and Sven Grundmann and Isabel Vela-Perez and Simon Brennecke and Nicolas Eicke and Jonas Rist and Sebastian Eckart and Salim Houamer and Ochbadrakh Chuluunbaatar and Yuri V. Popov and Igor P. Volobuev and Kai Bagschik and Maria Novella Piancastelli and Manfred Lein and Till Jahnke and Markus S. Schöffler and Reinhard Dörner},
journal= {arXiv preprint arXiv:1911.04780},
year = {2020}
}
Comments
7 pages, 4 figures