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- Kircher, Max, et al.
(författare)
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Kinematically complete experimental study of Compton scattering at helium atoms near the threshold
- 2020
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Ingår i: Nature Physics. - : Springer Nature. - 1745-2473 .- 1745-2481. ; 16:7, s. 756-760
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Tidskriftsartikel (refereegranskat)abstract
- Compton scattering is one of the fundamental interaction processes of light with matter. When discovered(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. In this regime, ionization by Compton scattering becomes an intriguing quantum phenomenon. Here, we report on a kinematically complete experiment studying Compton scattering off helium atoms in that regime. We determine the momentum correlations of the electron, the recoiling ion and the scattered photon in a coincidence experiment based on cold target recoil ion momentum spectroscopy, 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 such 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. Compton scattering experiments off helium atoms for photon energies close to the ionization threshold reveal that electrons are not only emitted in the direction of the momentum transfer but also backwards.
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| 2. |
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| 3. |
- Ueda, Kiyoshi, et al.
(författare)
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Roadmap on photonic, electronic and atomic collision physics : I. Light-matter interaction
- 2019
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Ingår i: Journal of Physics B. - : IOP PUBLISHING LTD. - 0953-4075 .- 1361-6455. ; 52:17
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Tidskriftsartikel (refereegranskat)abstract
- We publish three Roadmaps on photonic, electronic and atomic collision physics in order to celebrate the 60th anniversary of the ICPEAC conference. In Roadmap I, we focus on the light-matter interaction. In this area, studies of ultrafast electronic and molecular dynamics have been rapidly growing, with the advent of new light sources such as attosecond lasers and x-ray free electron lasers. In parallel, experiments with established synchrotron radiation sources and femtosecond lasers using cutting-edge detection schemes are revealing new scientific insights that have never been exploited. Relevant theories are also being rapidly developed. Target samples for photon-impact experiments are expanding from atoms and small molecules to complex systems such as biomolecules, fullerene, clusters and solids. This Roadmap aims to look back along the road, explaining the development of these fields, and look forward, collecting contributions from twenty leading groups from the field.
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