Razvan Gornea and Kevin Graham from the Department of Physics are helping unlock the secrets of the universe through their work on a next-generation experiment studying subatomic particles.
The Hyper-Kamiokande (Hyper-K) project is an ultra-large water Cherenkov detector currently being built in Hida City, Gifu, Japan. The cavern that houses this massive underground instrument is one of the largest human-made spaces excavated in bedrock.
With the cavern completed in July, the project has now entered its next phase: construction of the detector. Carleton, alongside our partners, is contributing to the development of a key component of the device. Once finished, it will be the largest water-based Cherenkov detector ever built.
Led by the University of Tokyo and the High Energy Accelerator Research Organization, Hyper-K is a major international scientific research collaboration involving approximately 630 researchers from 22 countries.
The Hyper-Kamiokande Particle Detector
The project aims to measure neutrino properties and interactions with unprecedented statistical precision. It will also search for proton decay and other physics phenomena. This work could help solve fundamental mysteries, such as the history of the evolution of the universe, and test Grand Unified Theories, the merging of three different interactions into a single unified force at high energies.
Hyper-K consists of a neutrino source, a far detector located 300 km away from the source, and multiple near detectors positioned within 1 km. With a fiducial mass 8.4 times larger than its predecessor, it includes the world’s largest underground water tank (260,000 cubic meters) and will be equipped with over 20,000 newly developed photomultiplier tubes (PMT), a type of photodetector that is extremely sensitive to light.
Hyper-K is located 650 meters beneath a mountain to protect against cosmic rays.
Carleton’s Involvement
Using complex experimental techniques require physicists to understand and control systematic errors to better than one percent. This calls for refined calibration methods at the far detector.
Razvan and Kevin are helping develop a type of mPMT, a high-granularity photon sensor used for calibrating and performance verification. The LED-mPMT provides superior pulsed light sources (sub-nanosecond duration) that play a unique role in monitoring water purity and the angular response of PMTs.
The Universities of Victoria and Regina assemble the parts before shipping them to Carleton for final integration and testing. Once complete, the components are then sent to Japan for installation.
“We’re proud of our participation in this important international collaboration,” said Rafik Goubran, Vice-President (Research and International). “It speaks to Carleton’s outstanding research excellence and the immense value our researchers can bring to large global projects.”
A total of 800 mPMTs will be constructed for Hyper-K, 200 of which are LED type. This project builds on the baseline FD mPMT developed by European colleagues, particularly in the Italian and Polish groups.
In Canada, the research and development (R&D) of the detector program is supported by an NSERC Subatomic Physics Discovery Grant led by TRIUMF, Canada’s particle accelerator centre, and two CFI Innovation Fund grants led by the University of Victoria, one of which is funding the development, assembly and testing of 210 LED-mPMTs (10 extra units for redundancy).
Most of the LED-mPMT production at Carleton will take place in 2026, at an average rate of four units per week.
“We would like to thank the research office for their support with this project, but also, in particular, with funding the laboratory infrastructure preparations at Carleton,” said Razvan.
Carleton also contributed to the R&D for all types of mPMTs and to far detection calibration studies in Monte Carlo, as well as to the installation and operation of the pilot Water Cherenkov Test Experiment (WCTE) at CERN earlier this summer.
Construction will proceed until the end of 2027, with physics data starting in January 2028. The Hyper-K experiment will run for about 15 years.
Read the official press release.