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Faculty of Science and Technology, Nova University of Lisbon

The R&D activities of LIBPhys-UNL are developed in the areas of atomic, molecular, nuclear physics and electronic & industrial automation instrumentation with applications to analytical methods, radiation detection, and biomedical engineering.

The experimental part is devoted, among many other projects, on physics of highly charged ions produced in both electron-cyclotron resonance source (ECRIS) and electron-beam ion source (EBIT).

High-precision measurements (few ppm accuracy) were performed with a vacuum double flat crystal spectrometer attached to an ECRIS [1, 2, 3], providing most accurate tests of quantum electrodynamics in the X-ray region.

More recently, we investigate the details of electron collision and recombination cross-sections of highly charged iron and tungsten produced by an electron beam ion trap (EBIT). Figure 1 shows a complete map of atomic processes in Ne-like Fe that generate lines of astrophysical interest.

Photon emission after electron collision/recombination for a set of electron and photon energies
Photon emission after electron collision/recombination for a set of electron and photon energies.

Experimental measurement of electron collision/recombination cross-sections in this atomic system was performed in a wide range of electron energies (300 – 1200 keV), establishing a compressive validation of all atomic processes accountable for photon lines of astrophysical interest.


Dr Pedro AMARO
Group Website

  • [1] P. Amaro et al., "Absolute Measurement of the Relativistic Magnetic Dipole Transition Energy in Heliumlike Argon", Physical Review Letters 109, 043005 (2012). [link to article]
  • [2] P. Amaro et al., "A vacuum double-crystal spectrometer for reference-free X-ray spectroscopy of highly charged ions", Radiation Physics and Chemistry 98, 132-149 (2014). [link to article]
  • [3] J. Machado et al., "High-precision measurements of n=2→n=1 transition energies and level widths in He- and Be-like argon ions", Physical Review A 97, 032517 (2018). [link to article]


Astrophysics Cross Section Measurements Dielectronic Recombination EBIT ECRIS Electron Impact Excitation Electron Impact Ionization Electronic Structure Calculations Highly Charged Ions Inelastic Scattering Iron Spectroscopy MCDF X-Ray Spectroscopy