At the summit of Mauna Kea · Observing since August 2026
ALOHA combines a compact particle detector array with Hyper Suprime Cam of Subaru Telescope to explore the nature of high-energy particle cascades induced by cosmic rays
At Subaru Telescope · Mauna Kea, Hawaiʻi
01 · About
The ALOHA Experiment operates four plastic scintillator-based particle detectors inside the Subaru Telescope enclosure on Mauna Kea. The array tracks charged particles from cosmic-ray extensive air showers together with the regular observation of Hyper Suprime-Cam. This hybrid observation aims to reveal the precise structure of air showers.
Fast plastic scintillator-based particle detectors provide particle arrival timing and pulse information from cosmic-ray air showers, with a compact DAQ designed for long-term remote operation.
CCD of Hyper Suprime-CamS's can provide information on each air shower particle's track working as an exceptionally large silicon detector.
The high-altitude environment places the detector closer to the maximum of air shower development while using the infrastructure of a world-leading optical observatory.
02 · Team
ALOHA brings together the people who design and operate the particle detectors, support observations at Subaru Telescope, and develop the joint analysis. Formal institution and contributor credits will be added as public lists are approved.
Surface-detector hardware, calibration, triggering, remote operations and data quality.
Site integration, safe operation inside the telescope enclosure and observing coordination.
Event matching, optical-signature searches and interpretation across the two instruments.
03 · Science
The first phase (August 2026~) will focus on understanding detector performance, building reliable event matching and searching HSC data for time-coincident signatures on CCD of HSC.
A high-energy primary particle initiates a cascade in the atmosphere.
The four scintillation detectors record the particle front and timing.
Candidate events are matched with the corresponding visits of HSC.
04 · News
News will update for important milestones and link to press releases.
ALOHA entered its first coordinated observing period with the Hyper Suprime-Cam!
The full SD array was installed and commissioned inside the telescope enclosure.
All detectors and system of ALOHA were transported to Hilo office of Subaru Telescope.
https://subarutelescope.org/jp/results/2023/10/11/3309.html (Japanese)
https://www.perc.it-chiba.ac.jp/news/2023/10/12/2537/ (Japanese)
https://www.omu.ac.jp/info/research_news/entry-08225.html (Japanese)