In Chile we can make complex technology that works
Jilberto Zamora Saá created ColdBox, a protective structure that blocks neutrons interfering with sensitive nuclear emulsion detectors studying neutrinos at the world's largest particle physics laboratory. Neutrinos are nearly undetectable subatomic particles that pass through matter without interaction, making them crucial for understanding the universe's origin and fundamental physics mysteries.
- Jilberto Zamora Saá, director of CTEPP at Universidad Andrés Bello, designed the ColdBox neutron shield
- The shield reduces neutron radiation by more than 1,000 times at the SND@LHC experiment
- Neutrinos are nearly massless, uncharged particles that pass through matter without interaction
- The research was published in the Journal of Instrumentation
- Chile became an associated member state of CERN in 2023
A Chilean researcher at Universidad Andrés Bello designed a neutron shield that reduces radiation interference by over 1,000 times, enabling the SND@LHC experiment at CERN to detect neutrinos more effectively.
Inside the world's largest particle physics laboratory, buried beneath the Swiss-French border, scientists face a problem that sounds almost poetic: how to photograph the invisible. Neutrinos—ghostly subatomic particles with almost no mass and no electrical charge—stream through the universe by the trillions every second, passing through planets, stars, and human bodies without leaving a trace. They carry secrets about the origin of the cosmos, about matter and antimatter, about the fundamental rules that govern reality. But detecting them is like trying to capture starlight with a broken camera.
At CERN, the European Organization for Nuclear Research, one experiment called SND@LHC was built to study neutrinos produced in the violent collisions of protons inside the Large Hadron Collider. The detector uses nuclear emulsions—essentially photographic film sensitive enough to record the rare moments when a neutrino actually interacts with matter. The problem was that the collider itself generates a storm of radiation: protons, neutrons, and other particles flooding the detector with noise. It was like trying to take a photograph in a dark room while someone keeps flashing a strobe light in your face.
Jilberto Zamora Saá, a physicist and director of the Center for Theoretical and Experimental Particle Physics at Universidad Andrés Bello in Santiago, designed a solution. Working from Chile, he used advanced computer simulations to engineer a structure called ColdBox—essentially a protective box that would shield the detector's sensitive emulsions from the neutron radiation battering them. The design was then built by a specialized technical team at the university's Faculty of Exact Sciences. The results were striking: the shield reduced neutron radiation by more than a thousand times. The detector could finally do its job. The signal came through clean.
"It worked so well that inside the system, the instruments practically detected no neutrons at all," Zamora explained. "The level was too low." The research was published in the Journal of Instrumentation, a peer-reviewed international journal dedicated to detector and instrumentation science.
For Zamora, the achievement carries weight beyond the physics itself. Chile became an associated member state of CERN in 2023, a recognition of the country's scientific capacity. This neutron shield, designed and built in Santiago and now operating at the world's premier particle physics facility, is proof of that capacity. It demonstrates that complex, functional technology can emerge from Chilean laboratories—technology that matters in the most important scientific experiments on Earth. "In Chile we can make complex technology that works and that is useful in the world's most important scientific experiments," Zamora said. The invisible particles continue their journey through the universe. Now, at least in one small corner of Switzerland, we have learned to see them.
Notable Quotes
It worked so well that inside the system, the instruments practically detected no neutrons at all, because the level was too low.— Jilberto Zamora Saá
In Chile we can make complex technology that works and that is useful in the world's most important scientific experiments.— Jilberto Zamora Saá
The Hearth Conversation Another angle on the story
Why does it matter that we detect neutrinos at all? What are we actually trying to learn?
Neutrinos carry information about some of the most violent and ancient events in the universe—supernovae, the core of the sun, the moments right after the Big Bang. They barely interact with anything, so they arrive almost unchanged. They're like messengers from places we can't reach any other way.
And the problem was that the detector itself was being drowned out by noise?
Exactly. Imagine trying to hear a whisper in a stadium full of screaming fans. The neutrons from the collider were like that noise—they were hitting the emulsion film and creating false signals, making it impossible to distinguish a real neutrino interaction from background radiation.
So Zamora's shield just... blocks the neutrons?
It reduces them by more than a thousand times. It's not that it stops them completely—that would be impossible. But it gets the noise down to a level where the detector can actually function, where the signal becomes readable.
And this was designed in Chile, not at CERN itself?
Yes. Zamora did the computational work in Santiago, then the university's technical team built it. That's significant because it shows the expertise exists here, not just in Europe. It's not just about one experiment—it's about what Chile can contribute to global science.
What happens now? Does this design get used elsewhere?
That's the question. If it works this well for neutrino detection, there may be applications in other experiments, other detectors. But first, the SND experiment continues, gathering data that was impossible to gather before.