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Mon, Mar 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
E-mail: misato@icrr.u-tokyo.ac.jp
Attachment
http://www.icrr.u-tokyo.ac.jp/public_relation/press_release/2014/20140331kagra/kagra_en.zip

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 : http://www.u-tokyo.ac.jp/public/public01_02_j.html
KEK : http://www.kek.jp/ja/NewsRoom/Release/20140331150000/
NAOJ :http://tamago.mtk.nao.ac.jp/spacetime/KAGRA_tunnel_j.html

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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Wed, Mar 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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Thu, Dec 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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Mon, Nov 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.
http://iopscience.iop.org/0264-9381/29/12/124007

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Thu, Oct 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;

http://gwdoc.icrr.u-tokyo.ac.jp/DocDB/0019/P1301917/001/MOU%20final%20signed%20131011.pdf

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

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Tue, Jul 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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Tue, Jul 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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Mon, Jun 10th, 2013

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

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Mon, May 13th, 2013

The doctor thesis of Dr.Izumi who use to be a doctorial student of NAOJ got Braccini Prize 2012 (https://wwwcascina.virgo.infn.it/StefanoBPrize2012.html ).
The award ceremony and lecture will be presented in May 24th 2013 in the
Pisa university.

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Mon, Apl 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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Tue, Apl 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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Wed, Jan 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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Fri, Jan 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.
http://www.gw.hep.osaka-cu.ac.jp/daschool/

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Sun, Dec 23rd, 2012

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

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Thu, Nov 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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Fri, Aug 31st, 2012

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

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Fri, Aug 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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Sun, Jul 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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Wed, Jun 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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Mon, Jun 18th, 2012

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


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Tue, May 22nd, 2012

The blasting at the Mozumi entrance has started.

before

after

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Tue, Apl 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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Tue, Mar 27th, 2012

The KAGRA logo was selected.

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Tue, Mar 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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Fri, Mar 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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Wed, Feb 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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Sat, Feb 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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Wed, Feb 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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Sat, Jan 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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Sat, Jan 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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Sat, Jan 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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Wed, Oct 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,
http://www.yamanashi-eiwa.ac.jp/~hirotaka/pub_lecture/poster.pdf

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Mon, Oct 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.

Place:
University of Tokyo, Kashiwa-campus, Frontier Sciences, Environmental Studies Building, 1st Floor, SF Hall.
(http://www.u-tokyo.ac.jp/campusmap/cam03_01_06_e.html)

Conference Page :
Here(http://www.icrr.u-tokyo.ac.jp/gr/Italy-Japan_program.pdf).

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Wed, Sep 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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Mon, Jul 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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Fri, Jun 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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Thu, May 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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Thu, May 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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Thu, Apl 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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Tue, Apl 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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Tue, Apl 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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Fri, Apl 1st, 2011

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

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Thu, Mar 31st, 2011

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

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Tue, Mar 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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Fri, Feb 18th, 2011

LCGT MOUs between LIGO and VIRGO were formally concluded.

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Sun, Feb 6th, 2011

Mainichi newspaper wrote up the new name application for LCGT.

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Thu, Dec 16th, 2010

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

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Wed, Nov 24th, 2010

Staff of Italy embassy visited CLIO with Desalva-sensei.

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Fri, Nov 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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Thu, Nov 18th, 2010

The film about the construction of LCGT has started.

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Wed, Nov 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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Tue, Nov 9th, 2010

Technical staff and postdoctoral researche recuruiting has started.

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Fri, Nov 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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Fri, Nov 5th, 2010

An assistant researcher recruiting has started.

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Wed, Nov 3rd, 2010

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

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Wed, Nov 3rd, 2010

LCGT call for a new charming name!

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Fri, Oct 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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Sat, Sep 25th, 2010

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

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Wed, Sep 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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Mon, Jun 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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