XII International Workshop on Ring Imaging Cherenkov Detectors - RICH2025

The concept of using the neutrino as an astronomical messenger is as old as the neutrino itself, and the challenge to open this new window on the high-energy universe has been technological in nature. We will describe how the IceCube Neutrino Observatory transformed a cubic kilometer of natural ice at the geographic South Pole into a neutrino telescope as well as discuss the technologies that...

The KM3NeT Collaboration is incrementally building two underwater Cherenkov neutrino telescopes in the Mediterranean Sea. Both telescopes share the same technology for neutrino detection, by studying Cherenkov radiation from secondary charged particles produced in neutrino interactions. Photomultipliers are a common choice for the detection of Cherenkov radiation, but the hostile underwater...

The IceCube Neutrino Observatory, though primarily designed for high-energy neutrinos, has become a powerful tool for studying MeV-scale neutrino bursts from astrophysical transients. This talk will provide an overview of recent efforts and developments aimed at enhancing IceCube’s capabilities in this energy regime, including searches for core-collapse supernovae, gamma-ray bursts, and...

In 2021, LHAASO observed a large number of PeV cosmic ray candidates in the Milky Way. We proposed to build a telescope with at least 30 times the sensitive volume of the IceCube detector, so as to observe those LHAAASO sources. In order to realize this project, we innovatively put forward a photosensitive detector unit based on a photomultiplier tube with a maximum photosensitive area of 20...

The Jiangmen Underground Neutrino Observatory (JUNO) is a state-of-the-art neutrino physics experiment located in South China. With 20 ktons of ultra-pure Liquid Scintillator, JUNO aims to achieve groundbreaking measurements, including the determination of Neutrino Mass Ordering and the precise measurement of three neutrino oscillation parameters with sub-percent precision. The central...

The Hyper-Kamiokande experiment is a next-generation underground water Cherenkov detector designed to explore CP violation, proton decay, and astrophysical neutrino sources with unprecedented sensitivity. To enhance photodetection capabilities, both the far detector (FD) and the Intermediate Water Cherenkov Detector (IWCD) incorporate novel multi-PMT modules. Each module integrates nineteen...

The Ring Imaging Cherenkov (RICH) detector aboard the Alpha Magnetic Spectrometer (AMS-02) has been operating successfully on the International Space Station since 2011. The RICH detector, based on a proximity focusing design, features a dual-radiator configuration with sodium fluoride tiles at the center surrounded by silica aero gel tiles, and a matrix of 680 multi-anode photomultiplier...

LHAASO using large area water Cherenkov for CR air shower detection in the energy range from 0.5 to 20 TeV for gamma ray astronomic observation of mainly extragalactic objects. The water cherenkov detectors are burried 2.5 m beneath the surface to measure muons in showers in LHAASO. The largest muon detector array with the active area of 40k square meters in the CR detction history provides...

The Pierre Auger Observatory is the world’s largest cosmic-ray observatory, dedicated to the study of ultra-high-energy (UHE) cosmic rays with energies above 10¹⁷ eV. This overview talk presents recent results and ongoing research across a wide range of topics aimed at elucidating the origin, composition, and interactions of these enigmatic particles. Key highlights include...

The Latin American Giant Observatory (LAGO) is a collaborative initiative that deploys a network of low-cost, autonomous Water Cherenkov Detectors (WCDs) across Latin America and Spain. Initially focused on detecting gamma-ray bursts at high-altitude sites, LAGO has evolved into a multidisciplinary platform for astroparticle physics, space weather studies, and environmental monitoring. Its...

The Southern Wide-field Gamma-Ray Observatory (SWGO) will be a next-generation gamma-ray observatory located in the Southern Hemisphere. Building upon the experience of previous and current ground-based particle array observatories, SWGO will feature a large detection area, a high-altitude site, and a southern location to explore the gamma-ray sky up to PeV energies. Following the recent site...

The Cherenkov Telescope Array Observatory (CTAO) is a project whose objective is to advance knowledge of the gamma-ray sky with the largest gamma-ray observatory ever built. The CTAO will consist of two Imaging Atmospheric Cherenkov Telescope (IACT) arrays, with more than 60 telescopes. One of them is under construction in the northern hemisphere, at the Roque de los Muchachos Observatory...

In 2024, the Large High Altitude Air Shower Observatory (LHAASO) released its first catalog of ultra-high-energy (UHE) gamma-ray sources, identifying over 40 such sources. This marked a significant advancement in UHE gamma-ray astronomy. Many of these sources exhibit extended features, necessitating next-generation Imaging Atmospheric Cherenkov Telescopes (IACTs) with higher angular resolution...

The maximum photon detection efficiency (PDE) of silicon photomultipliers (SiPMs) can be comparable to or even exceed that of photomultiplier tubes (PMTs). There are experiments where the signal is measured in the presence of strong background light. Considering PDE alone can lead to wrong conclusions and results, one needs to accurately assess the signal-to-noise ratio. Imaging atmospheric...

Imaging with Cherenkov telescopes was a breakthrough for gamma ray astronomy. However, by pushing Cherenkov telescopes to ever higher precision and ever larger sizes our upcoming generation of telescopes has reached the intrinsic limits of imaging itself. Aberrations limit our field-of-view and our possible angular resolution in the gamma-ray sky. The square-cube-law escalates the costs to...