Latest News

木曜日, 9月 20th, 2018

Dr. Yuichiro Sekiguchi, KAGRA’s collaborator and Associate Professor at Toho University is awarded the 12th Yukawa-Kimura prize for his research on study of “Numerical-relativity simulation of binary neutron star mergers with realistic microphysics.” Congraturations!

Yukawa-Kimura Prize Homepage

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金曜日, 8月 3rd, 2018

The second issue of KAGRA Scientific Congress Newsletter is released and now online at

KAGRA Scientific Congress (KSC) is the decision making body of KAGRA collaborators. The aims of KSC are to discuss and to make decisions upon KAGRA science(Seeherefor the details).


page-1 From Phase 1 to Phase 2
page-2 Directions: Steps to the 2019 observation
page-3 Kamioka Local: Subgroup orientation, Kagra River, Science Cafe
page-5 Recent meetings: F2F at Osaka City Univ. , KIW at Ewha Womans Univ.
page-6 Poster Award Winners
page-7 Next F2F at Toyama, LOGOs
page-8 Visit Virgo
+ KAGRA meeting schedule, We hear that …, etc.

Related topic:

Premiere Issue of KAGRA Scientific Congress Newsletter

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金曜日, 5月 25th, 2018

May 25, 2018

The 4th KAGRA International Workshop will be held in Ewha Woman’s University, located in Seoul, Korea in June 29-30, 2018.

The main theme of the KAGRA International Workshop (KIW) centers on the KAGRA project, but also encompasses all related fields such as other gravitational wave experiments, gravitational wave sciences, and multi- messenger astronomy. Everybody interested in contributing to the KAGRA project and gravitational wave science in general is welcome to join the meeting.

A public lecture by Prof. Takaaki Kajita, the PI of KAGRA Project on the topic of “Gravitational wave astronomy with KAGRA” is also held during the workshop.

Visit workshop website for the details and registration (deadline: June 15) .

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水曜日, 4月 11th, 2018

On March 30, Louisiana State University’s Professor Gabriela González, the former Spokesperson of LIGO Scientific Collaboration, visited the experimental site of KAGRA.  Assistant Professor Keiko Kokeyama, who moved from LSU to ICRR in 2015, guided her in the KAGRA underground site. Prof. González enjoyed to see the status of preparation of the experiment.

Professor Gabriela González(center) and Dr. Keiko Kokeyama(left) in the KAGRA arm tunnel.

Visitors are carefully watching the installation work of sapphire mirror in the cryogenic vessel.

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日曜日, 4月 1st, 2018

The premiere issue of KAGRA Scientific Congress Newsletter is released and now online at

KAGRA Scientific Congress (KSC) is the decision making body of KAGRA collaborators. The aims of KSC are to discuss and to make decisions upon KAGRA science(See here for the details).

Today April 1st, some members of KSC released KSC NewsLetter in order to exchange and share KSC’s activities. It’s free and open to public. Please enjoy!

page-1 Phase-1 operation starts on April 23
page-2 Directions: Towards joining LIGO/Virgo’s O3
page-3 Kamioka: New office is open!
page-4 Upcoming meetings: KIW Ewha Womans Univ.
page-4 Upcoming meetings: Face-2-Face at Osaka City Univ.
page-5 Lab. interview:  Academia Sinica
page-6 Physics: What Stephen Hawking did in Relativity?
+ Recent review talks, KAGRA meeting schedule, We hear that …,  etc

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金曜日, 2月 12th, 2016

Feb. 12th, 2016

Message from KAGRA on the discovery of Gravitational Wave signal by LIGO-Virgo collaborations

We, the KAGRA collaboration, congratulate the LIGO and Virgo collaborations for the discovery of the gravitational wave signal. It is a historic discovery where the whole field of gravitational waves and general relativity have been waited for.

It is really exciting news, because it is now clear that the studies of gravitational waves and massive compact objects, such as black holes and neutron stars, can be made by the present generation gravitational wave detectors including KAGRA.

KAGRA would like to complete the construction, achieve the high sensitivity and join the international gravitational wave network as soon as possible so that KAGRA can contribute to the new field of gravitational wave astronomy. Because KAGRA is located underground and going to use cryogenic mirrors, KAGRA is particularly suited to study gravitational wave signals below about 100 Hz, where many signals of mergers of black hole binaries are expected, as observed by LIGO.

In addition to the merger of black hole binaries, there are many astronomical objects to be studied with gravitational waves. For example, KAGRA wants to detect a birth of a black hole created by a coalescence of binary neutron stars and resolve the mystery of short gamma ray bursts with the other gravitational wave detectors and with the partners of multi-messenger astronomy.

Takaaki Kajita,
for the KAGRA collaboration

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水曜日, 10月 7th, 2015

Professor Kajita, who is the PI of KAGRA, won the Nobel prize in physics !!

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金曜日, 6月 13th, 2014

Our research proposal entitled ” First detection of Gravitational Waves using Cryogenic Laser Interferometer” was selected as a Specially Promoted Research of JSPS in 24th April 2014. The leader of this research is T.Kajita who is also a PI of KAGRA project.

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月曜日, 3月 31st, 2014

Excavation of KAGRA’s 7 km Tunnel Now Complete
March 31, 2014

On March 31, 2014, the team of the Large-Scale Cryogenic Gravitational Wave Telescope (KAGRA) completed the excavation of its L-shaped tunnel with two 3 km arms. Including two access tunnels, a total length of 7,697 m has been hollowed out 200 m below the surface of Mt. Ikenoyama in Kamioka—beside the site of Super-Kamiokande—where the construction of a 3-km-scale cryogenic interferometer will soon begin. This interferometer has been designed to directly detect gravitational waves for the first time ever.

KAGRA is an international project involving 231 scientists from 31 institutions, principally operated by ICRR(Institute for Cosmic Ray Research) with two main joint-research institutions, KEK (High energy accelerator research organization) and NAOJ (National Astronomical Observatory). Its aim is to construct 3-km-scale Fabry-Perot Michelson Interferometer underground at Kamioka to detect gravitational waves. Gravitational waves, derived from Einstein’s general theory of relativity, are ripples in the curvature of spacetime that propagate at the speed of light. The first indirect proof of their existence was proposed by Dr. Hulse and Dr. Taylor in 1974 who found a binary system of neutron stars, whose decrease in orbital period was well described by the loss of energy through gravitational radiation. In addition, the astronomers of the BICEP2 experiment at the South Pole recently reported that they had found the signature of primordial gravitational waves imprinted in the B-mode polarization of the Cosmic Microwave Background—further evidence of gravitational waves if confirmed. However, gravitational waves have yet to be detected directly in a form in which their waveforms are evident. The direct detection of gravitational waves will not only validate our understanding of gravity and spacetime but also open up a whole new field of gravitational wave astronomy by enabling the physics of strong gravitational fields to be tested, and enabling direct observations of mysterious objects such as black holes, which are not possible through the observation of electromagnetic waves.

Gravitational waves manifest themselves as extremely small changes in the distance between two points in spacetime. Direct gravitational wave detectors therefore detect a change in the metric. However, even the strongest gravitational waves produced during the merger of binary neutron stars and binary black holes typically cause a variation of length of the size of a hydrogen atom over the distance between the Earth and the Sun. Furthermore, such mergers occur once every 100,000 years in our Galaxy. KAGRA aims to increase the detection frequency to several times per year by employing an ultra high-sensitivity metric-variation detector (that can detect change of one part per trillion of trillion) to expand the observation range to include many galaxies. The key to a successful gravitational wave detector is to minimize background noises such as seismic noise and thermal noise to achieve extremely high sensitivity limited only by the quantum noise of the laser used in the interferometer. KAGRA will be constructed 200 m underground to reduce seismic noise to a hundredth of that at the ground surface, and its mirrors that reflect lasers back and forth will be cooled to temperature of 20 K to reduce thermal noise. KAGRA’s quiet underground environment under Mt. Ikenoyama—also known for its lithological characteristic of hard Hida gneiss rock—is now, after 20 months of excavation, ready to host the world’s most sensitive gravitational wave detector.

KAGRA’s construction started in 2010. The L-shaped tunnel with two 3 km arms and two access tunnels is located 200 m under the surface of Mt. Ikenoyama and has a slope of 0.3% to drain spring water effectively. A construction company, Kashima, started to excavate the access tunnels from the Mozumi area in May 2012, and from the Atotsu area in June 2012. After the excavation of central laboratory area near the Atotsu entrance, the crew split into two groups; one working on the “X-arm”, which extends 3 km in the east-northeast direction, and the other working on the “Y-arm”, extending in the north-northwest direction. The Mozumi crew continued to excavate from the other end of the Y-arm up to a distance of 1,165 m, where they stopped to deal with a possible abnormal amount of spring water at the fault. In December 2013, the Y-arm was finally blasted open from the Atotsu side. Following the completion of the Y-arm, the X-arm continued to be extended from one direction and was completed on March 31, 2014. The full excavation length is 7,697 m. During the construction, no serious lithological issues arose; however, on several occasions an unexpectedly large quantity of spring water hampered smooth operations during the excavation period. Kashima coped with such problems efficiently and professionally, even breaking the national record for the excavation speed by the NATM method, achieving a rate of 359 m per month.

The collaboration plans to install laboratory facilities and the detector components in the coming fiscal year, in preparation for the initial operation at the end of 2015. The full-scale operation is planned to start in JFY2017.

Media Contact for Further Inquiries
PR Office: Misato Hayashida
TEL: 04-7136-5148

This announcement are reported in home pages in The University of Tokyo (UT), High energy accelerator research organization (KEK), and National Astronomical Observatory Japan (NAOJ).
UT :

Fig1. The red line shows the seismic vibration level at the ground (Kashiwa Campus) and the green line shows that of 1,000 m underground at Kamioka (CLIO). It has been shown that the seismic vibration level at 200 m below the mountain surface is nearly the level shown in green.

Fig 2. A bird’s eye view of the Large-Scale Cryogenic Gravitational Wave Telescope (KAGRA), an L-shaped laser interferometer with two 3 km arms.

Fig 3. A panorama photo taken in December 2012 at the central branching point near the Atotsu entrance.

Fig 4. KAGRA’s Y-arm that extends from the Atotsu side to the Mozumi side was blasted open in December 2013.

Fig 5. A view of KAGRA’s Y-arm.

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水曜日, 3月 5th, 2014

GWADW2014 in which we discuss about the future technique for GW detection will be held in Takayama-city, Gifu-prefecture, Japan from 25th May to 31st May.
The web page is here.

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木曜日, 12月 5th, 2013

Since 2012 May, the Y arm tunnel of KAGRA was excavated from Mozumi area and Atotsu area. In Dec/5/2013, this Y arm tunnel finally became one tunnel.

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月曜日, 11月 25th, 2013

Prof. Somiya’s article has been selected by the Editorial Board of Classical and Quantum Gravity (CQG) to be one of the journal’s Highlights of 2012-2013.

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木曜日, 10月 17th, 2013

MOU between KAGRA and Dept. of Phys. Hanoi Nat. Univ. of Education
was signed on Oct. 11, 2013. You can find the MOU at;

People from Dept. of Phys. Hanoi Nat. Univ. of Education would join KAGRA in the near future.

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火曜日, 7月 23rd, 2013

The KAGRA talk event is being held in Inotani-sekisho museum in front of the JR inotani station. The lecturer are S.Miyoki, T.Uchiyama, M.Ohashi, S.Kawamura and O.Miyakawa. Especially, in September 8th, two talks about KAGRA will be presented in a festival “Inotani-sekisyo friendly festival “.

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火曜日, 7月 9th, 2013

Yoshiki high school students visited CLIO and SK in July 9th. This event was also reported in a local newspaper.

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月曜日, 6月 10th, 2013

The 4th Korea-Japan Workshop was held in Osaka Univ. The web site is here

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月曜日, 5月 13th, 2013

The doctor thesis of Dr.Izumi who use to be a doctorial student of NAOJ got Braccini Prize 2012 ( ).
The award ceremony and lecture will be presented in May 24th 2013 in the
Pisa university.

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月曜日, 4月 22nd, 2013

April 19th 2013, an Italy-Japan Workshop about gravitational wave physics has been held in the Embassy of Italy. This is one of events related with Italy year 2013 in Japan for their cultural communication.

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火曜日, 4月 9th, 2013

Pro. Takahashi was awarded a prize for encouragement of Yamanashi Academy as a promising young researcher in the field of research, education and technology in Yamanashi prefecture.

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水曜日, 1月 30th, 2013

In Jan/30/2013, the project titled “The construction of Gravitational Wave Astronomy” was selected as one of Core to Core program of JSPS. The leader is Pro.Kawamura.

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金曜日, 1月 18th, 2013

KAGRA Data analysis school wiil be held in NAOJ during Fev 20th ~ 22th.
You can find application form and information in this page.

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日曜日, 12月 23rd, 2012

3rd Korea-Japan Workshop was held in Dec 21~22 2012.
The program was here.

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木曜日, 11月 1st, 2012

Pro. Endo, the president of Toyama University visited CLIO. After that young scientists in GW group had a meeting with Pro. Endo, Pro.Moriwaki, Pro.Hirobayashi and Pro.Matsushima who are members of Toyama University at GWPO Kamioka branch building.
The President of Toyama University visited CLIO.1
The President of Toyama University visited CLIO.2
The President of Toyama University visited CLIO.3

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金曜日, 8月 31st, 2012

ET-KAGRA thermal noise workshop was held in Jena University, Germany.
The workshop report is in here

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金曜日, 8月 17th, 2012

KAGRA Advisory Board Meeting was held in ICRR Kashiwa Campus. KAGRA EO members were evaluated about the progress of KAGRA, management, and got many suggestions from the Advisory Board members.

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日曜日, 7月 8th, 2012

In 8th July, a workshop about KAGRA with the department of physics and engineer of Toyama University was held in the Toyama University.

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水曜日, 6月 27th, 2012

In June 17th, Uchiyama-kun who is ICRR member gave a lecture on KAGRA in the GSA seminar promoted by Hida academy.

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月曜日, 6月 18th, 2012

New Atotsu tunnel excavation has started. The excavation of Mozumi is also all right.

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火曜日, 5月 22nd, 2012

The blasting at the Mozumi entrance has started.



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火曜日, 4月 17th, 2012

An External Review for KAGRA project was held in ICRR from 17th April to 20th. The committee chaired by Dr. Michael E. Zucker evaluated the KAGRA designs, progress, and risks of each subgroup and made some advices. We would like to make assure the success of KAGRA project with these External Review’s reports.

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火曜日, 3月 27th, 2012

The KAGRA logo was selected.

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火曜日, 3月 13th, 2012

KAGRA project PI, Pro.Kajita was awarded a prize of the Japan Academy of
2012 for “the discovery of atmospheric neutrino oscillation”.

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金曜日, 3月 2nd, 2012

Yuki Susa, a member of the KAGRA collaboration at Tokyo Tech,
has been chosen as the representative of master students in
the Department of Physics. Title of his master thesis is
“Optimal signal amplification by weak measurement.”

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水曜日, 2月 29th, 2012

In 28th February, A Master thesis of T.Sekiguchi got an ICRR Director Award in the ICRR Master and Doctor Thesis Workshop.
His master thesis title is “Modeling and Simulation of Vibration Isolation System”.

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土曜日, 2月 18th, 2012

Members of the House of Councilors, who belong to committee on education, visited in Kamioka Observatory, Super Kamiokande, XMASS and CLIO.

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水曜日, 2月 15th, 2012

Thermal noise reduction in CLIO was published in Physical Review Letters.

Summary by Author T.Uchiyama.

“Thermal fluctuation, as evidenced by Brownian motion, has been a well-known phenomenon, and it remains the fundamental limitation for certain ultraprecise measurements such as interferometric gravitational wave (GW) detectors and laser frequency stabilisation using a rigid Fabry-Perot reference cavity. One promising approach for reducing such fluctuations is to use a low-mechanical-loss material at a low temperature. Here, we experimentally demonstrate for the first time a reduction in a mirror’s thermal fluctuation in a GW detector with suspended sapphire mirrors from the Cryogenic Laser Interferometer Observatory (CLIO) at 17K and 18K. The majority of previous efforts to reduce thermal fluctuations in such mirrors have focused on the use of low-loss materials at room temperature. Thus, this achievement provides a new method for overcoming the limitations by thermal fluctuations at room temperature. This cryogenic mirror technology will be used in advanced GW detectors such as KAGRA formerly called the Large-Scale Cryogenic Gravitational Wave Telescope (LCGT), the construction of which began in 2010 in Japan, and the Einstein Telescope in Europe.”

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土曜日, 1月 28th, 2012

LCGT finally got new nickname “KAGRA”. KA means “Kamioka”, and GRA means Gravity and Gravitational wave.

A detail report is shown in this page.

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土曜日, 1月 21st, 2012

LCGT ground breaking ceremony was held in Mozumi, Kamioka-cho, Hida-city, Gifu prefecture.
Some photos about ceremony are shown in this page.

LCGT ground breaking ceremony was written up in several newspaper.
(web page on Gifu newspaper).

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土曜日, 1月 14th, 2012

Korea-Japan Workshop was held in Korea University to promote LCGT project. Collaborations in laser development, vibration isolation, quantum measurement and so on were discussed.

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水曜日, 10月 12th, 2011

In 2011 November 5th, a lecture entitled ” Challenge to the Mystery of the Universe from Yamanashi !” will be presented by Dr. H. Takahashi and Mr. Tsugane in the Yamanashi-Eiwa school festival.
Please find in detail in,

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月曜日, 10月 3rd, 2011

The European Gravitational Observatory (EGO) and the Institute for Cosmic Ray Research (ICRR) organize a meeting, under the patronage of the Italian Embassy in Tokyo, with the aim to explore the collaboration between Italy and Japan on the Gravitational Wave research with the future interferometric detectors in Italy (advanced Virgo) and Japan(LCGT). The 3rd generation perspectives, thanks to the Einstein Telescope (ET) project will be investigated too and the ELiTES Japanese-European collaborative FP7 project, between ET and LCGT, will be prepared.

University of Tokyo, Kashiwa-campus, Frontier Sciences, Environmental Studies Building, 1st Floor, SF Hall.

Conference Page :

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水曜日, 9月 14th, 2011

Dr.Miyakawa (ICRR.UT staff) will give a lecture in Nagoya University GCOE program named as “Quest for fundamental principles in the universe”.
The title is “Detection of gravitational waves from underground in Kamioka-mine”.
Please see this page in detail.

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月曜日, 7月 11th, 2011

In the afternoon July 24th, a science cafe live about LCGT project will
be broadcasted in the home page of Niconico-douga. This program is
organized in cooperation with Asahi newspaper and ICRR UT.

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金曜日, 6月 17th, 2011

Yoko Ogawa-san who is a japanese famous novelist kindly accepted to be a chairman of a LCGT naming committee, and selected a new hypocrism for LCGT project from about 630 applications. We are very sorry, but please wait until around August~September 2011 for public announcement about this new hypocrism.

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木曜日, 5月 12th, 2011

An explanatory meeting about LCGT vacuum ducts temporary stock in the Kamioka-railway tunnels will be held in Higashimozumi, Kamioka-cho, Hida-city in 18th May.

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木曜日, 5月 12th, 2011

A meeting for LCGT new name selection was put off due to 3.11 earthquake will be held in 16th June 2011.

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木曜日, 4月 21st, 2011

Students and their teachers of Sizhuoka-Kita high school visited Super-Kamiokand, XMASS and CLIO as an event of Super Science High school (SSH). In the morning, they received lectures about SK, XMASS, CLIO and their related physics of neutrino, dark matter, gravitational waves. In the afternoon, they entered the Kamioka mine and visited each facilities.

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火曜日, 4月 19th, 2011

An explanatory meeting about LCGT vacuum ducts temporary stock in the Kamioka-railway tunnels will be held in Urushiyama, Kamioka-cho, Hida-city in 22nd April.

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火曜日, 4月 12th, 2011

Yamanashi nichi-nichi newspaper wrote up a company in this region accepted an order for LCGT vacuum system in April 8th.

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金曜日, 4月 1st, 2011

Gravitational Wave Project Office was established in April 1st 2011.

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木曜日, 3月 31st, 2011

Gravitational Wave Project Office will be established in April 1st 2011.

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火曜日, 3月 29th, 2011

An Emeritus professor of Tokyo-toritsu University Ikemoto and members of ABCEJ visited Super-Kamiokande, XMASS and CLIO. The members of ABCEJ are mainly private middle school and high school chemistry teachers around Tokyo.

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金曜日, 2月 18th, 2011

LCGT MOUs between LIGO and VIRGO were formally concluded.

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日曜日, 2月 6th, 2011

Mainichi newspaper wrote up the new name application for LCGT.

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木曜日, 12月 16th, 2010

Physics today Journal wrote up LCGT on the 35th page in December issue.

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水曜日, 11月 24th, 2010

Staff of Italy embassy visited CLIO with Desalva-sensei.

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金曜日, 11月 19th, 2010

“Thermal-noise-limited underground interferometer CLIO” was selected as an oustanding article in the Classical and Quantum Gravity hilight of 2009-2010.

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木曜日, 11月 18th, 2010

The film about the construction of LCGT has started.

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水曜日, 11月 17th, 2010

The department chief of the academic organization section of the Ministry of Education, Culture, Sports, Science and Technology of Japan visited CLIO. Professor Jim Hough who is one of leader of GEO600 also visited CLIO.

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火曜日, 11月 9th, 2010

Technical staff and postdoctoral researche recuruiting has started.

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金曜日, 11月 5th, 2010

Yoko Ogawa-sensei who is a famous award-winning novelist agreed to be a chairman to decide the new LCGT name.

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金曜日, 11月 5th, 2010

An assistant researcher recruiting has started.

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水曜日, 11月 3rd, 2010

A key to understand the Universe – Gravitational Wave detection” by a LCGT collaborator, Dr. Kentaro Somiya was introduced

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水曜日, 11月 3rd, 2010

LCGT call for a new charming name!

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金曜日, 10月 15th, 2010

A public lecture about LCGT will be held in November 27th. This lecture is one of the National University Festa.

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土曜日, 9月 25th, 2010

University of Tokyo, Executive Management Program students (20) visited CLIO.

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水曜日, 9月 15th, 2010

The President of the University of Tokyo, Professor Hamada and the regent of the University of tokyo, Professor Kozima visited CLIO.

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月曜日, 6月 21st, 2010

Professor Takeda and Assistant Professor Miyamaru and their students (Shinshu University, Department of Science, Physics division, Solid state physics division) visited CLIO.

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