Nuclear astrophysics, measured a kilometre underground.

I measure the nuclear reactions that power stars, at the energies at which stars actually run them. Most of that work happens at LUNA, under 1400 m of Gran Sasso rock, where the cosmic-ray background is six orders of magnitude lower than at the surface and cross sections of picobarns become reachable.

A measurement, though, is only ever a handful of points in a narrow window of energy. Turning those points into the quantity astrophysics needs — a rate at stellar temperatures, often far below anything measurable — is R-matrix theory's job. Since 2025 I have been the maintainer and lead developer of AZURE2, the reference R-matrix code for the field, and I sit on the IAEA INDEN-LE committee that evaluates light-element cross sections.

This site collects both halves: notes on the theory, and evaluations you can open and run yourself in the browser.