ICARUS experiment detecting neutrinos.

Unveiling the Invisible: How the ICARUS Experiment is Rewriting Neutrino Physics

Theo Raines in Science & Nature December 2025 • 4 min read.

"Delve into the groundbreaking ICARUS experiment at LNGS, exploring its innovative technology and pivotal role in understanding neutrino behavior and its implications for fundamental physics."

The ICARUS (Imaging Cosmic And Rare Underground Signals) experiment represents a significant leap in neutrino research. Located at the Gran Sasso National Laboratory (INFN-LNGS) in Italy, this project employs the world's largest Liquid Argon Time Projection Chamber (LAr-TPC), containing approximately 600 tons of liquid argon. Its primary goal is to observe and analyze rare events, with a particular focus on neutrino interactions.

Neutrinos, often called "ghost particles" because of their ability to pass through matter almost unaffected, hold vital clues about the universe's fundamental properties. The ICARUS detector's unique design allows for high-precision imaging and calorimetry, enabling scientists to reconstruct neutrino events with unprecedented accuracy. Since it began operating in the summer of 2010, ICARUS has been collecting data from both cosmic rays and the CNGS (CERN Neutrinos to Gran Sasso) neutrino beam.

The ICARUS experiment utilizes a completely uniform imaging and calorimetry system to allow for complete event reconstruction, as well as detector main features and performances. Furthermore, the recent precise measurement of neutrino velocity, aligning with the speed of light, and the quest for the Cherenkov radiation analogue, for superluminal neutrinos will be discussed.

How ICARUS Captures the Unseeable: The Liquid Argon TPC

At the heart of ICARUS lies the Liquid Argon Time Projection Chamber (LAr-TPC), a detection technique first proposed by C. Rubbia in 1977. This technology provides three-dimensional imaging of any ionizing event within the argon. When a charged particle interacts with the liquid argon, it causes atomic ionization and emits light in the vacuum ultraviolet (VUV) range at 128 nm.

The operational principle hinges on the behavior of ionization tracks within highly purified liquid argon. A uniform electric field (typically 500 V/cm) allows these tracks to be transported over significant distances with minimal distortion. The low diffusion coefficient ensures that tracks remain undistorted for at least 1.5 meters. A network of electrodes (wires) at the end of the drift path continuously senses and records the signals induced by drifting electrons.

Here's a breakdown of how it works:

Ionization: Charged particles interacting with the liquid argon create ionization tracks.
Drift: An electric field guides these ionization electrons towards the wire planes.
Detection: The wire planes detect the signals, allowing for 3D event reconstruction.
Purity is Key: High purity levels in the liquid argon are crucial for minimizing electron loss and maintaining signal integrity. Impurities can cause the loss of electrons.

The non-destructive read-out of ionization electrons by charge induction allows for the detection of signals from electrons crossing subsequent wire planes with different orientations. This provides multiple projective views of the same event, enabling precise calorimetric measurement and space point reconstruction. The absolute time of an ionizing event, combined with the electron drift velocity (approximately 1.6 mm/µs at 500 V/cm), determines the absolute position of the track.

ICARUS: A Cornerstone for Future Discoveries

The ICARUS T600 experiment, with its large Liquid Argon Time Projection Chamber, is pivotal in the study of rare events and neutrino interactions. Its data acquisition since mid-2010 at LNGS, using the CNGS beam from CERN-SPS, targets the exploration of νµ → ντ oscillation, LSND-like νe excess, atmospheric neutrinos, and proton decay.

ICARUS’s exceptional imaging capabilities, spatial and calorimetric resolutions, and electron/pion separation enable event reconstruction and identification. It also made significant contributions to addressing the super-luminal neutrino challenge.

As scientists continue to probe the universe's deepest secrets, the ICARUS experiment stands as a testament to human ingenuity and the relentless pursuit of knowledge. Its legacy will undoubtedly shape the future of neutrino physics and our understanding of the cosmos.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1051/epjconf/20147000055, Alternate LINK

Title: The Icarus Expriment At Lngs Underground Laboratory

Subject: General Medicine

Journal: EPJ Web of Conferences

Publisher: EDP Sciences

Authors: Nicola Cancia

Published: 2014-01-01

Everything You Need To Know

What is the primary goal of the ICARUS experiment, and what kind of events does it focus on observing?

The ICARUS experiment, located at the Gran Sasso National Laboratory (INFN-LNGS), primarily aims to observe and analyze rare events, with a specific focus on neutrino interactions. By using a large Liquid Argon Time Projection Chamber (LAr-TPC), ICARUS seeks to precisely reconstruct neutrino events to better understand the fundamental properties of these elusive particles. This includes studying neutrino oscillations and searching for anomalies that could challenge the Standard Model of particle physics. The experiment also explores atmospheric neutrinos and investigates potential proton decay.

How does the Liquid Argon Time Projection Chamber (LAr-TPC) work within the ICARUS experiment to detect particles?

The Liquid Argon Time Projection Chamber (LAr-TPC) within ICARUS works by leveraging the ionization process within highly purified liquid argon. When charged particles interact with the argon, they create ionization tracks. A uniform electric field guides these electrons towards wire planes. The wire planes detect signals allowing for 3D event reconstruction. High purity of the liquid argon is crucial to minimize electron loss and maintain signal integrity.

Where is the ICARUS detector located, and why is this location important for the experiment's success?

The ICARUS detector is located at the Gran Sasso National Laboratory (LNGS) in Italy. This underground location provides significant shielding from cosmic rays and other background radiation, allowing ICARUS to more effectively detect rare neutrino interactions and other rare events. The depth of the laboratory helps to reduce interference, thus enhancing the sensitivity and precision of the experiment. ICARUS uses the CERN Neutrinos to Gran Sasso (CNGS) neutrino beam.

How does the ICARUS experiment contribute to our understanding of neutrino behavior and fundamental physics?

The ICARUS experiment contributes to our understanding of neutrino behavior by providing high-precision imaging and calorimetry of neutrino interactions. This allows scientists to study neutrino oscillations, such as the search for νµ → ντ oscillation, and to look for anomalies like the LSND-like νe excess. By precisely measuring neutrino properties, ICARUS helps to refine the Standard Model of particle physics and explore potential new physics beyond it. The experiment's findings also have implications for understanding the role of neutrinos in the universe's evolution.

How does the Liquid Argon Time Projection Chamber (LAr-TPC) allow for a complete event reconstruction?

The Liquid Argon Time Projection Chamber (LAr-TPC) allows for a complete event reconstruction because it offers a completely uniform imaging and calorimetry system. The non-destructive read-out of ionization electrons by charge induction allows for the detection of signals from electrons crossing subsequent wire planes with different orientations. This provides multiple projective views of the same event, enabling precise calorimetric measurement and space point reconstruction. The absolute time of an ionizing event, combined with the electron drift velocity determines the absolute position of the track.