For four focused days in downtown Barcelona, the Nuclei in the Cosmos (NIC) School turned a notoriously sprawling discipline into something graspable—and testable—by lunchtime. Held June 10–13 at the Royal Academy of Sciences and Arts of Barcelona (RACAB) on La Rambla, 115, the School offered a compressed, hands‑on primer geared to PhD students and early‑career researchers, timed as a ramp‑up to the main NIC XVIII symposium in Girona (June 15–20).
The organizers kept the value proposition clean: teach the essentials of nuclear astrophysics—from stellar evolution and nucleosynthesis to detectors, beams, and observational spectroscopy—then put those ideas to work with practical sessions (including remote observations on the Nordic Optical Telescope) and a Big Bang Nucleosynthesis lab. The format was the opposite of conference bloat: short, crisp lectures; tool‑heavy exercises; and a faculty drawn from labs and observatories that actually generate the field’s data.
The setup: a school with a mission—and a cap
NIC School is explicitly designed as the on‑ramp to the biennial NIC meeting—long described as a central forum for nuclear astrophysics—so that newcomers can speak the language when the big questions land later in the week at Girona’s Palau de Congressos. Capacity was capped at 50 participants; fees were set at €250 (lunches and a school dinner included), with a small pool of fee waivers for students already registered for the symposium. A venue note doubled as local color: RACAB sits inside the Teatre Poliorama near Plaça Catalunya.
Program, in plain English
The faculty list read like a cross‑section of the field:
Stellar explosions (Alan C. Calder, Stony Brook): from novae to supernovae and neutron‑star mergers—i.e., where r‑process pathways light up.
Stellar evolution (Alessandro Chieffi, INAF): how stars build the periodic table in hydrostatic phases before anything explodes.
High‑energy astrophysics (Roland Diehl, MPE): what gamma‑ray lines tell us about nucleosynthesis sites.
Detectors, beams & targets (Fairouz Hammache, IJCLab): the hardware that turns beam time into cross‑sections.
Spectroscopy & stellar abundances (Andreas Korn, Uppsala): converting spectra into elements and isotopes.
Experimental nuclear physics (Richard Longland, NC State): how we measure the reaction rates that drive the models.
Nuclear theory (Xavier Roca‑Maza, ICCUB): calculating the inputs you can’t (yet) measure.
Cosmochemistry (Sheri Singerling, Goethe): what meteorites and presolar grains say about stellar forensics.
Hands‑on blocks did the glue work: a Big Bang Nucleosynthesis session to push through a full reaction network workflow, plus remote nighttime observations at the Nordic Optical Telescope (NOT) on La Palma—arranged courtesy of the ChETEC‑INFRA network. The point wasn’t sightseeing; it was to tie stellar spectra to abundance tables the students would then feed into models.
Translation: NIC School collapsed the lab–sky loop into a single week: measure, model, compare—then repeat with better priors.
What the School did exceptionally well
1) Bridging lab and sky.
The lecture flow mirrored the actual scientific pipeline: detectors and cross‑sections → reaction rates and networks → stellar abundances from spectra → model validation. By the time students hit the NOT session, “tables” had turned into astrophysical levers—you could see which rates mattered for which features in a kilonova light curve or a metal‑poor star’s spectrum. That through‑line—rates to r‑process and back again—made the abstractions stick.
2) Reproducible modelling as a habit.
The BBN hands‑on and theory blocks forced good hygiene: notebooks, versioned inputs, and results traceable back to specific cross‑section sets. It’s the right muscle memory given the validation debates waiting at NIC XVIII (where r‑, s‑, and i‑process yields, EOS choices, and network solvers will be argued on stage). The School didn’t treat “reproducibility” as a manifesto; it made it a workflow, which is the only way it sticks. (NIC XVIII’s topic grid—r‑/p‑process, s‑/i‑process, nuclear reactions, abundances—is exactly where that rigor pays off.)
3) Community building.
The best value wasn’t a single slide—it was a shared vocabulary. A detector specialist and a simulation PhD could solve the same problem by lunch, because they’d just built the same toy model and looked at the same spectrum the night before. NIC has always been a people pipeline; the School compresses months of ramp‑up into four days, so the symposium can skip the remedial and go straight to frontier questions.
Why Barcelona before Girona?
The split is intentional. Barcelona’s RACAB offers a quiet, central location made for teaching and code—small rooms, short walks, no distractions—while Girona’s Palau de Congressos is built for a plenary‑only symposium where hundreds of specialists argue about the fine print of galactic chemical evolution, reaction networks, and nucleosynthesis sites. The School’s timeline (ending Friday) left a weekend buffer for travel and brain reset before the Sunday welcome in Girona.
A few practicals (that tell a story)
Nordic Optical Telescope tie‑in. Beyond the NIC bubble, NOT is a workhorse 2.56‑m facility whose remote observing slots are now a training norm across Europe—boosted by ChETEC‑INFRA, which stitches together the field’s labs, telescopes, and compute. (You learn a lot faster when the telescopes are real.)
Limited to 50 participants. Scarcity keeps the ratio tight; students actually talk to lecturers.
€250 fee with lunch and a dinner baked in. Inclusion isn’t just policy—it’s a budget line.
The broader NIC arc
NIC is biennial and it matters. Since 1990, it’s become the meeting where nuclear physics, astronomy, and cosmochemistry actually cross‑pollinate. NIC XVIII’s topic list read like a map of the field’s hard problems: BBN and the early universe; presolar grains; nuclear reactions; neutrinos; r/s/i processes; high‑density matter and neutron‑star EOS; and galactic chemical evolution. The promise of the School is that by day one in Girona, students aren’t spectators—they can interrogate a rate, parse a spectrum, or debug a network with the adults. That raises the floor for everyone.
Takeaway
NIC School 2025 did the simple thing well: it taught what matters and how to do it. The recipe—rates you can trust, models you can reproduce, and spectra you can defend—sends its alumni into NIC XVIII with enough shared context to argue about the right things. That’s the point. In a field where one cross‑section can swing an abundance and one systematic can flip an interpretation, the fastest way to build the future is to train people who see the whole loop.
Barcelona handled that part. Girona gets the fireworks.
