OSECHI

About This Guide

Mon, 01 Jan 0001 00:00:00 +0000

This page is under construction.

Details about who this guide is written for and what it aims to help you do will be added soon.

About This Guide

Mon, 01 Jan 0001 00:00:00 +0000

This page is under construction.

Details about who this guide is written for and what it aims to help you do will be added soon.

About This Guide

Mon, 01 Jan 0001 00:00:00 +0000

This page is under construction.

Details about who this guide is written for and what it aims to help you do will be added soon.

High Energy Accelerator Research Organization (KEK)

Mon, 01 Jan 0001 00:00:00 +0000

1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan

Kazuki Ueno

Mon, 01 Jan 0001 00:00:00 +0000

Associate Professor, Graduate School of Science, Osaka University

osechi.gitlab.io

Mon, 01 Jan 0001 00:00:00 +0000

https://gitlab.com/osechi/osechi.gitlab.io

The official website for the compact cosmic ray detector OSECHI (planned).

What are Cosmic Rays?

Mon, 01 Jan 0001 00:00:00 +0000

Cosmic rays are high-energy particles that rain down on Earth from outer space. When cosmic rays enter Earth’s atmosphere, they collide with atomic nuclei in the air and produce secondary particles. Of these, muons are the representative particles that reach the surface.

Types of Cosmic Rays
#

Primary Cosmic Rays
#

Particles traveling directly from space, observed above the atmosphere.

Our Vision

Mon, 01 Jan 0001 00:00:00 +0000

Operate a measurement instrument with your own hands, and use it to measure cosmic rays yourself. We want to bring that experience to more people — that’s the future we’re working toward.

Muon measurement is a topic covered even in university physics labs. Until now, though, it required expensive, large, high-voltage measurement equipment. This project develops OSECHI, a detector that’s compact and easy to handle while still delivering serious, research-grade measurement, and brings it into familiar settings — a school classroom, a local event, and more.

History

Mon, 01 Jan 0001 00:00:00 +0000

“OSECHI,” the name of our detector, traces back to a household item we stumbled on partway through building a prototype. Here’s the story of the OSECHI project so far.

Getting Started
#

The OSECHI project began in June 2019, when a group of volunteers first came together. We initially named the project “Tan-Q,” and started planning and developing workshops built around a cosmic-ray detector.

FAQ

Mon, 01 Jan 0001 00:00:00 +0000

Here are some questions we’re often asked about the OSECHI project.

How do I join?
#

We currently use a referral-based system for joining. Please contact us, or reach out to a member at a nearby university or research institution.

Do I need prior knowledge of cosmic rays to participate?
#

Yes — you don’t need any prior knowledge of cosmic rays, physics, or programming to participate. This is a hands-on project where you learn by doing. Come join us and have fun.

Contact

Mon, 01 Jan 0001 00:00:00 +0000

Contact Us
#

We’d love to hear from you! Please reach out with any questions or feedback about OSECHI.

Contact information will be available soon.

For more information, please visit our main website or check back soon for contact details.

Kyushu University

Mon, 01 Jan 0001 00:00:00 +0000

744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan

Takeshi Nakamori

Mon, 01 Jan 0001 00:00:00 +0000

Professor, Faculty of Science, Yamagata University

tutorials

Mon, 01 Jan 0001 00:00:00 +0000

https://gitlab.com/osechi/tutorials

Beginner-friendly tutorials on measurement and analysis using OSECHI.

What are Muons?

Mon, 01 Jan 0001 00:00:00 +0000

Properties of Muons
#

Muons (μ particles) are elementary particles belonging to the same family as electrons (leptons).

Property	Value
Mass	~207 times the electron mass (105.7 MeV/c²)
Charge	−1 (antimuon: +1)
Spin	1/2
Mean lifetime	~2.2 microseconds (rest frame)

Muons are far heavier than electrons and have high penetrating power, passing through most matter with ease.

Why Do They Reach the Ground?
#

Muons are created in the upper atmosphere (about 15 km altitude). With a rest-frame lifetime of ~2.2 μs, they should only travel about 660 m at light speed. Yet they reach the surface thanks to special relativity.

Datasets

Mon, 01 Jan 0001 00:00:00 +0000

Datasets used in OSECHI papers are available from this page.

Coming soon.

How Does Solar Activity Affect Cosmic Rays?

Mon, 01 Jan 0001 00:00:00 +0000

The amount of cosmic rays reaching Earth isn’t constant — it changes over time. One major reason is the activity of the Sun.

The Solar Wind Shields Galactic Cosmic Rays
#

The Sun constantly emits the solar wind, a stream of charged particles (protons, electrons, and others) that carries magnetic field throughout the solar system. Cosmic rays arriving from outside the galaxy (galactic cosmic rays) are partly deflected by this field, making it harder for them to reach the inner solar system.

kurikintons

Mon, 01 Jan 0001 00:00:00 +0000

https://gitlab.com/osechi/kurikintons

Arduino-compatible firmware for OSECHI’s microcontroller (ESP32-WROOM-32E).

Masayoshi Shoji

Mon, 01 Jan 0001 00:00:00 +0000

Technical Specialist, Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)

University of Miyazaki

Mon, 01 Jan 0001 00:00:00 +0000

1-1 Gakuen Kibanadai-nishi, Miyazaki-shi, Miyazaki 889-2192, Japan

What is a Scintillator?

Mon, 01 Jan 0001 00:00:00 +0000

A scintillator is a material that emits visible or ultraviolet light when radiation — a charged particle or gamma ray — passes through it. This light emission is called scintillation.

Why It Glows
#

When a charged particle passes through a scintillator, it temporarily excites the atoms it passes near, bumping electrons into a higher energy state. As the electrons return to their original (ground) state, the energy difference is released as light. Charged particles like muons continuously trigger this emission as they travel through matter.

comochi_combu

Mon, 01 Jan 0001 00:00:00 +0000

https://gitlab.com/osechi/comochi_combu

An archive of OSECHI’s PCB design files.

Nagoya University

Mon, 01 Jan 0001 00:00:00 +0000

Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan

Shota Takahashi

Mon, 01 Jan 0001 00:00:00 +0000

Designated Assistant Professor, Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya University

What is a Photodetector?

Mon, 01 Jan 0001 00:00:00 +0000

The light emitted by a scintillator is extremely faint — far too dim to see with the naked eye. A photodetector amplifies this faint light into a measurable electrical signal.

Types of Photodetectors
#

There are two broad approaches to converting and amplifying light into an electrical signal: vacuum-tube based and semiconductor based.

Photomultiplier Tubes (PMTs)
#

A Photo Multiplier Tube (PMT) is a vacuum tube that converts and amplifies light into an electrical signal.

Participation Guidelines

Mon, 01 Jan 0001 00:00:00 +0000

Introduction
#

These guidelines summarize the basic mindset and a few requests for anyone taking part in activities using OSECHI. They are not meant to be enforced as strict rules — please use them as a reference when you’re unsure how to proceed with a specific activity.

1. Purpose and Values
#

The OSECHI community aims to advance education and science outreach through the development and use of the compact cosmic ray detector OSECHI. We value an environment where anyone can participate regardless of their position — researchers and outreach staff at universities and research institutes, teachers, students, and others.

Code Of Conduct

Mon, 01 Jan 0001 00:00:00 +0000

Code of Conduct
#

The OSECHI community aims to be a place where anyone can participate safely, regardless of position or experience. This page summarizes our code of conduct within the community.

For our day-to-day approach to activities and a few requests, please also see the Community and Participation Guidelines.

This code of conduct is based on the Contributor Covenant, version 2.1, widely adopted across open source communities.

kazunoko

Mon, 01 Jan 0001 00:00:00 +0000

https://gitlab.com/osechi/kazunoko

A lightweight serial communication library for OSECHI.

Osaka University

Mon, 01 Jan 0001 00:00:00 +0000

Taikanezan-cho, Toyonaka, Osaka, Japan

Tamaki Yoshioka

Mon, 01 Jan 0001 00:00:00 +0000

Professor, Faculty of Arts and Science, Kyushu University

What is Coincidence?

Mon, 01 Jan 0001 00:00:00 +0000

Even with a scintillator and photodetector working together, not every signal that comes out is caused by a muon. Thermal and electrical noise can produce signals that look a lot like the real thing. Coincidence is a technique that combines multiple detector layers to filter out this noise and select only the events where a muon truly passed through.

Threshold
#

A photodetector’s signal always contains a mix of genuine muon signals and faint background noise. The boundary value used to distinguish noise from signal is called the threshold; an event is only recorded when the signal exceeds it.

omochi

Mon, 01 Jan 0001 00:00:00 +0000

https://gitlab.com/osechi/omochi

A detector simulator for OSECHI.

Satoshi Mihara

Mon, 01 Jan 0001 00:00:00 +0000

Professor, Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)

The Graduate University for Advanced Studies (SOKENDAI)

Mon, 01 Jan 0001 00:00:00 +0000

Shonan Village, Hayama, Miura, Kanagawa 240-0193, Japan

What is Air Shower Observation?

Mon, 01 Jan 0001 00:00:00 +0000

When a primary cosmic ray enters the atmosphere, the single particle branches out again and again, producing a swarm of countless secondary particles. This phenomenon is called an air shower. By the time it reaches the ground, the shower has become a group of particles arriving simultaneously across a wide area.

How a Shower Spreads
#

When a primary cosmic ray collides with a nucleus in the upper atmosphere, it produces secondary particles such as pions. These particles go on to react with other nuclei or decay, multiplying the particle count in a cascading chain reaction.

datemaki

Mon, 01 Jan 0001 00:00:00 +0000

https://gitlab.com/osechi/datemaki

A data management tool for OSECHI (planned).

University of Toyama

Mon, 01 Jan 0001 00:00:00 +0000

3190 Gofuku, Toyama-shi, Toyama 930-8555, Japan

What is Muography?

Mon, 01 Jan 0001 00:00:00 +0000

Muography uses the high penetrating power of muons to image the internal structure of large objects. Just as X-rays image the human body, muography “sees through” buildings, volcanoes, and pyramids.

How Muography Works
#

As cosmic-ray muons pass through matter, they travel in a straight line while gradually losing energy. Denser material absorbs more muons, so the number of muons observed on the far side of an object varies with the density of the material along the path they traveled.

Yuuki Nakano

Mon, 01 Jan 0001 00:00:00 +0000

Assistant Professor, Faculty of Science, University of Toyama

kuromame

Mon, 01 Jan 0001 00:00:00 +0000

https://gitlab.com/osechi/kuromame

A lightweight online monitor for OSECHI (planned).

Masaki Tanida

Mon, 01 Jan 0001 00:00:00 +0000

Graduate Student, Graduate School of Sciences, Kyushu University

What is Citizen Science in Cosmic Ray Observation?

Mon, 01 Jan 0001 00:00:00 +0000

Cosmic ray research once required large, dedicated equipment found only at universities and research institutes. As detectors have become smaller and cheaper in recent years, the field has grown into a form of citizen science, where schools and individuals can take part in genuine measurement.

What is Citizen Science?
#

Citizen science is a style of research where members of the public — not just professional researchers — take part in observation, data collection, and analysis. It has produced results across many fields, from amateur astronomers discovering new celestial objects to volunteers logging biodiversity sightings.

Yamagata University

Mon, 01 Jan 0001 00:00:00 +0000

1-4-12 Kojirakawa-machi, Yamagata-shi, Yamagata 990-8560, Japan

cookbooks

Mon, 01 Jan 0001 00:00:00 +0000

https://gitlab.com/osechi/cookbooks

A collection of DAQ recipes using kazunoko and datemaki.

Waseda University Honjo Senior High School

Mon, 01 Jan 0001 00:00:00 +0000

239-3 Kurisaki, Honjo-shi, Saitama 367-0032, Japan

What Open Questions Remain in Cosmic Ray Research?

Mon, 01 Jan 0001 00:00:00 +0000

Cosmic rays have been studied for over a century since their discovery in 1912, yet some fundamental questions remain unanswered. Here are a few of the open problems researchers around the world are still working on.

Where Do the Highest-Energy Cosmic Rays Come From?
#

Observations have confirmed that, on rare occasions, cosmic rays reach Earth carrying an almost unbelievable amount of energy for a single particle — these are called ultra-high-energy cosmic rays. The highest energies ever recorded far exceed what humanity’s largest particle accelerator, the LHC, can produce.

Muons and New Physics

Mon, 01 Jan 0001 00:00:00 +0000

The muons we’ve discussed so far are “cosmic-ray muons,” produced when cosmic rays collide with the atmosphere. Elsewhere, researchers also produce large numbers of muons artificially with accelerators, studying their properties in precise detail to probe the limits of particle physics’ fundamental laws.

Measuring a Muon’s Tiny Deviation
#

Place a muon in a magnetic field and it behaves like a tiny magnet, wobbling like a spinning top. This wobbling motion is called precession, and the strength of the wobble is captured by a quantity called g-2 (the anomalous magnetic moment). g-2 can be calculated from theory with extraordinary precision, then compared directly against a measured value from experiment. Past experiments have reported a g-2 value that deviates slightly from the theoretical prediction, drawing attention as a possible hint of an as-yet-undiscovered particle or force.

Muons and Underground Experiments

Mon, 01 Jan 0001 00:00:00 +0000

The muon is the star of the show in a cosmic-ray measurement like OSECHI’s, but for many other experiments it’s treated as background — unwanted noise that sometimes turns it into an unwelcome intruder.

Why Muons Get in the Way
#

Roughly 10,000 muons rain down on every square meter of the Earth’s surface each minute. For experiments where keeping background to an absolute minimum is critical — searches for neutrino interactions or dark matter, for instance — this flood of muons leaves countless signals in a detector, burying the real signal researchers are looking for.

Muons and Accelerators

Mon, 01 Jan 0001 00:00:00 +0000

Muons produced in bulk by an accelerator power more than just precision measurements — they’re also put to work in applied research. One application drawing particular attention in recent years is using muons to investigate cultural artifacts, and researchers around the world are also, right now, building accelerators purpose-built for muons.

Seeing Inside Cultural Artifacts With Muons
#

Accelerator-made muons are also put to work in collaboration with archaeology, history, and conservation science — the field devoted to preserving and restoring cultural artifacts. When a negatively charged muon is aimed at an object, it gets captured by an atomic nucleus and, in the process, emits X-rays characteristic of that particular element (muonic X-rays). By measuring these X-rays, researchers can map an object’s elemental distribution deep below the surface, unlike conventional X-ray analysis, which can only probe near the surface, all without cutting into or damaging it in any way.

National Institute of Technology, Niihama College

Mon, 01 Jan 0001 00:00:00 +0000

7-1 Yagumo-cho, Niihama-shi, Ehime 792-8580, Japan

Oita University

Mon, 01 Jan 0001 00:00:00 +0000

700 Dannoharu, Oita-shi, Oita 870-1192, Japan

We Will Hold "Hirameki Tokimeki Science" — Watch the Sun with Neutrinos: How Do We Block the Troublesome Cosmic-Ray Muons? — at University of Toyama!

Sun, 06 Sep 2026 00:00:00 +0000

On Sunday, September 6, 2026, we will hold the Japan Society for the Promotion of Science’s “Hirameki Tokimeki Science — Welcome to the University Lab! KAKENHI” program “Watch the Sun with Neutrinos — How Do We Block the Troublesome Cosmic-Ray Muons?” at the Gofuku Campus of the Faculty of Science, University of Toyama. The event will let 20 high school students experience particle and astrophysics research through lectures and hands-on activities.

We Held "Tan-Q — The Mystery of the Universe! The Wonder of Cosmic Rays" at Osaka University!

Sun, 08 Feb 2026 00:00:00 +0000

On February 8, 2026, we held the cosmic ray exploration event “Tan-Q — The Mystery of the Universe! The Wonder of Cosmic Rays” at Osaka University’s Toyonaka Campus in Osaka. The event let five high school students experience hands-on science using OSECHI.

Associate Professor Mizuki Yoshioka (Kyushu University) led the seminar, speaking about what cosmic rays are. From the OSECHI project, Associate Professor Yoshioka was joined by Associate Professor Kazuki Ueno (Osaka University), Specially Appointed Assistant Professor Shota Takahashi (Nagoya University), Shoji (KEK), Professor Takeyuki Nakamori (Yamagata University), Professor Satoru Mihara (KEK / SOKENDAI), and graduate students Yamada and Aramaki (Osaka University).

We Held a Development Retreat at University of Toyama!

Sat, 01 Nov 2025 00:00:00 +0000

On November 1 and 2, 2025, we held an “OSECHI Development Retreat” at University of Toyama. The OSECHI project normally holds regular meetings online, but about once a year we bring members together in person for a concentrated push on development.

This retreat included a first in-person meeting with the University of Toyama members who joined the project this year, and discussion was lively. On the development side, we redesigned OSECHI’s PCB and worked hands-on through how to combine the electronic parts and configure the initial setup, completing five OSECHI detectors by the end. The retreat further strengthened collaboration among members and marked an important step forward for future development.

We Gave a Talk on OSECHI at the Scintillator Enhancement Workshop 2025

Tue, 28 Oct 2025 00:00:00 +0000

From October 28 to 29, 2025, the Scintillator Enhancement Workshop 2025 was held at the Ginga Hall, Faculty of Science and Engineering, Iwate University. The workshop is part of Platform A, a KEK detector development project focused on improving scintillators — the light-emitting materials used to detect cosmic rays and other radiation. As part of the workshop, Seiki Tanida, a graduate student at Kyushu University, gave a talk titled “Development of 3D-printed scintillators for compact cosmic-ray detectors.”

We Held a Development Retreat at Yamagata University!

Sat, 16 Nov 2024 00:00:00 +0000

On November 16 and 17, 2024, we held an “OSECHI Development Retreat” at Yamagata University. The OSECHI project normally holds regular meetings online, but about once a year we bring members together in person for a concentrated push on development.

A key goal of this retreat was to have students actually use “haniwers,” OSECHI’s data acquisition software, hands-on. I had been developing this software on my own up to this point, but having multiple people use it together surfaced unexpected bugs and areas for improvement, giving us valuable feedback for future work.

Our fun-Q Project Proceedings Published in the ICRC2023 Proceedings

Sat, 28 Sep 2024 00:00:00 +0000

A proceedings titled “墳Q (fun-Q) project: muography of Japanese ancient mounds by high school students” was published in Proceedings of Science (PoS).

The fun-Q project is muography (muon tomography) of Japanese ancient mounds by high school students, carried out through interdisciplinary collaboration. The team consists of high school students and teachers, scientists, engineers, communicators, curators, and archaeologists. The students are divided into groups, working with experts in both archaeological and physics research and combining the results of their studies. The first target was Akiyama Koshinzuka Kofun, located near the students’ school. The team conducted a Ground Penetrating Radar (GPR) survey and cosmic-ray measurement using OSECHI, a Japanese-style cosmic-ray muon detector developed for outreach and education.

Our OSECHI Proceedings Published at ICRC2023

Fri, 27 Sep 2024 00:00:00 +0000

A proceedings titled “Development of Japanese-style cosmic-ray muon detector for outreach and education” was published in Proceedings of Science (PoS).

Few citizens or students interested in particle physics and astrophysics have the chance to work with real research equipment such as accelerators, telescopes, and detectors, since these tend to be expensive. Recent technological developments have made it possible to build low-cost detectors, and this proceedings introduces the structure and prototype performance of OSECHI, a low-cost, compact cosmic-ray muon detector, along with examples of its use in outreach.

We Held "The Mystery of the Universe! The Wonder of Cosmic Rays" Measurement Experience at Saji Astro Park!

Sat, 17 Aug 2024 00:00:00 +0000

On August 17, 2024, the “Saji Astro Park Science Program” was held at Saji Astro Park in Tottori. As the closing session of a day filled with talks on topics like decarbonization, artificial shooting stars, and X-ray astronomy, a cosmic ray measurement experience titled “The Mystery of the Universe! The Wonder of Cosmic Rays” was held, led by the OSECHI group as instructors.

Participants split into five teams and measured the arrival rate of cosmic rays while changing the detector’s angle. After the measurements, each team shared its results with the whole group, and everyone considered why their measured distributions took the shape they did.

We Held "Tan-Q — The Mystery of the Universe! The Wonder of Cosmic Rays" at Nogake Community Center!

Sat, 17 Feb 2024 00:00:00 +0000

On February 17, 2024, we held the cosmic ray exploration event “Tan-Q — The Mystery of the Universe! The Wonder of Cosmic Rays” at Nogake Community Center in Fukuoka, as a community outreach program of the Graduate University for Advanced Studies (SOKENDAI). The event let participants from 5th grade up experience hands-on science using OSECHI.

The event was held in two parts.

In the first part, a seminar, Professor Takeyuki Nakamori of Yamagata University’s Faculty of Science spoke about what cosmic rays are.

Taking OSECHI Into an Ancient Burial Mound: Cosmic-Ray Research with a High School

Wed, 09 Aug 2023 00:00:00 +0000

From August 9 to 10, 2023, the OSECHI group teamed up with Waseda University Honjo Senior High School to carry out a measurement study using OSECHI at Akiyama Koshinzuka Kofun, a horizontal-entry round burial mound in Honjo, Saitama Prefecture.

Akiyama Koshinzuka Kofun is a round burial mound about 34 m in diameter and 5 m high, built in the late 6th century, with a horizontal-entry stone chamber (about 7.7 m long) opening to the south-southwest. It’s one of the mounds making up the Akiyama Kofun cluster, designated a Honjo City historic site and a Saitama Prefecture important site, and its internal structure is already known.

We Held "Cosmic Ray Measurement Experience 2023" at Nagoya University!

Sun, 30 Jul 2023 00:00:00 +0000

On July 30, 2023, the “Cosmic Ray Measurement Experience 2023” was held at the Kobayashi-Maskawa Institute (KMI), Nagoya University, in Aichi. The event was organized as a public program timed to coincide with the 38th International Cosmic Ray Conference (ICRC2023), which was being held at Nagoya University.

Co-hosted by KMI and Kasoku Kitchen, the event was open to junior high, high school, and technical college students, who built their own Cosmic Watch and used it to measure cosmic rays.

We Helped Out at the Osaka Science Museum's "Measure Cosmic Rays with a Cosmic Ray Detector!"

Sun, 06 Nov 2022 00:00:00 +0000

On November 6, 2022, Kasoku Kitchen hosted “Measure Cosmic Rays with a Cosmic Ray Detector!” at the Osaka Science Museum in Osaka. Open to participants from 5th grade through high school, it was a hands-on program where participants built their own Cosmic Watch and used it to observe cosmic rays.

From the OSECHI project, Associate Professor Kazuki Ueno (Osaka University) and Masaki Miyataki took part as staff, helping participants with their builds and introducing the OSECHI project.

We Held "Tan-Q — Exploring the Mystery of the Universe Through Cosmic Rays" at the Miraikan!

Sat, 19 Dec 2020 00:00:00 +0000

On December 19, 2020, we held the cosmic ray exploration event “Tan-Q — Exploring the Mystery of the Universe Through Cosmic Rays” at the National Museum of Emerging Science and Innovation (Miraikan) in Tokyo, as a community outreach program of the Graduate University for Advanced Studies (SOKENDAI). The event let junior high and high school students, teachers, and members of the public experience hands-on science using a small cosmic ray detector.

We Held a Cosmic Ray Exploration Workshop "Tan-Q" at Hiroo Gakuen!

Mon, 13 Jan 2020 00:00:00 +0000

On January 13, 2020, we held the cosmic ray exploration workshop “Tan-Q” at Hiroo Gakuen Junior and Senior High School in Tokyo, together with junior high and high school students from across the country, doing a hands-on cosmic ray measurement exercise using cosmic ray detectors.

Participants split into four teams and measured how the rate of cosmic rays reaching a detector changed between the upper floors of a building and ground level.

We Held a Cosmic Ray Observation Event at S-BIRD in Nagano!

Sat, 05 Oct 2019 00:00:00 +0000

On October 5, 2019, we held the cosmic ray observation event “Invisible Cosmic Rays See Everything! — Experience Cutting-Edge Particle and Astrophysics —” at S-BIRD, a hub for industrial promotion and talent development in Iida City, Nagano Prefecture. The event was open to junior high, high school, and technical college students nationwide, and included an activity presentation by students from Hiroo Gakuen High School.

The event was held in two parts.

OSECHI

About This Guide

About This Guide

About This Guide

High Energy Accelerator Research Organization (KEK)

Kazuki Ueno

osechi.gitlab.io

What are Cosmic Rays?

Types of Cosmic Rays #

Primary Cosmic Rays #

Our Vision

History

Getting Started #

FAQ

How do I join? #

Do I need prior knowledge of cosmic rays to participate? #

Contact

Contact Us #

Kyushu University

Takeshi Nakamori

tutorials

What are Muons?

Properties of Muons #

Why Do They Reach the Ground? #

Datasets

How Does Solar Activity Affect Cosmic Rays?

The Solar Wind Shields Galactic Cosmic Rays #

kurikintons

Masayoshi Shoji

University of Miyazaki

What is a Scintillator?

Why It Glows #

comochi_combu

Nagoya University

Shota Takahashi

What is a Photodetector?

Types of Photodetectors #

Photomultiplier Tubes (PMTs) #

Participation Guidelines

Introduction #

1. Purpose and Values #

Code Of Conduct

Code of Conduct #

kazunoko

Osaka University

Tamaki Yoshioka

What is Coincidence?

Threshold #

omochi

Satoshi Mihara

The Graduate University for Advanced Studies (SOKENDAI)

What is Air Shower Observation?

How a Shower Spreads #

datemaki

University of Toyama

What is Muography?

How Muography Works #

Yuuki Nakano

kuromame

Masaki Tanida

What is Citizen Science in Cosmic Ray Observation?

What is Citizen Science? #

Yamagata University

cookbooks

Waseda University Honjo Senior High School

What Open Questions Remain in Cosmic Ray Research?

Where Do the Highest-Energy Cosmic Rays Come From? #

Muons and New Physics

Measuring a Muon’s Tiny Deviation #

Muons and Underground Experiments

Why Muons Get in the Way #

Muons and Accelerators

Seeing Inside Cultural Artifacts With Muons #

National Institute of Technology, Niihama College

Oita University

We Will Hold "Hirameki Tokimeki Science" — Watch the Sun with Neutrinos: How Do We Block the Troublesome Cosmic-Ray Muons? — at University of Toyama!

We Held "Tan-Q — The Mystery of the Universe! The Wonder of Cosmic Rays" at Osaka University!

We Held a Development Retreat at University of Toyama!

We Gave a Talk on OSECHI at the Scintillator Enhancement Workshop 2025

We Held a Development Retreat at Yamagata University!

Types of Cosmic Rays
#

Primary Cosmic Rays
#

Getting Started
#

How do I join?
#

Do I need prior knowledge of cosmic rays to participate?
#

Contact Us
#

Properties of Muons
#

Why Do They Reach the Ground?
#

The Solar Wind Shields Galactic Cosmic Rays
#

Why It Glows
#

Types of Photodetectors
#

Photomultiplier Tubes (PMTs)
#

Introduction
#

1. Purpose and Values
#

Code of Conduct
#

Threshold
#

How a Shower Spreads
#

How Muography Works
#

What is Citizen Science?
#

Where Do the Highest-Energy Cosmic Rays Come From?
#

Measuring a Muon’s Tiny Deviation
#

Why Muons Get in the Way
#

Seeing Inside Cultural Artifacts With Muons
#