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2017 Fiscal Year Annual Research Report

Studying supernova explosions via their neutrino emissions

Planned Research

Project AreaGravitational wave physics and astronomy: Genesis
Project/Area Number 17H06365
Research InstitutionThe University of Tokyo

Principal Investigator

ヴァギンズ マーク  東京大学, カブリ数物連携宇宙研究機構, 教授 (90509902)

Co-Investigator(Kenkyū-buntansha) 住吉 光介  沼津工業高等専門学校, 教養科, 教授 (30280720)
小汐 由介  岡山大学, 自然科学研究科, 准教授 (80292960)
Project Period (FY) 2017-06-30 – 2022-03-31
Keywordsgravitational wave / supernova explosion / neutrino / neutron detection / hydrodynamic simulation
Outline of Annual Research Achievements

One of the primary sources of near-field gravitational waves [GW], core collapse supernova explosions are among the most dramatic and important events to take place in the universe. Supernova neutrinos, famously observed from SN1987A, provide a unique and vital probe into the inner dynamics of these events. Released together with GW during the initial stellar collapse, neutrinos and GW are both certain to travel through any obscuring dust or gas and remain undiminished upon their arrival at Earth. Neutrinos also carry information regarding the end state of the star: for explosions within our galaxy, collapses into neutron stars or black holes, the eventual sources of far-field GW, can be differentiated via observations of neutrino emissions.
During FY2017, we began preparations to upgrade the existing Super-Kamiokande [SK] detector to an advanced-technology, gadolinium-loaded supernova neutrino detector. The first step involved enhancing its online data processing capability to extract the most detailed, accurate supernova neutrino data as rapidly as possible, in order to get word out to the astronomical, neutrino, and GW communities. This was accomplished via the purchase and installation of three custom-built, 28-core high-performance computers in the SK control room. In addition, using the K Computer, 6D Boltzmann supernova simulations were run to explore the explosion mechanism and provide the neutrino spectra, theoretically extracting basic characteristics of neutrino signals emitted from the collapse of massive stars.

Current Status of Research Progress
Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

Our ultimate goal is to make theory and experiment work together so we will be ready to make the best possible observations of the next galactic explosion and maximize our extraction of information on the explosion mechanism, progenitor, and nuclear physics ingredients.
We have accomplished what we set out to do this year, and are making good progress toward this ultimate goal. What's more, we have already begun forming strong functional links between our experimental and theory members, vital for efficient future progress in understanding supernova explosions.

Strategy for Future Research Activity

During FY2018, Super-Kamiokande will be drained of water, internally refurbished, and completely inspected. Lessons learned in the pathfinder EGADS project regarding detector cleanliness and material selection will be applied to make SK ready for the addition of gadolinium.This will be the first time for Super-Kamiokande to be drained and serviced since 2006. There will be four main tasks:
1) fix a longstanding water leak in the SK tank; 2) clean up the interior of the detector (i.e., rust removal and re-passivation of the stainless steel surfaces); 3) replace those photomultiplier tubes which have failed since the last maintenance, and; 4) install additional piping inside the tank for better circulation of Gd-loaded water.
After the detector is refilled with ultrapure water, a new Gd-capable selective water filtration system will be commissioned and its ability to maintain the clarity of SK's pure water will be demonstrated. After that, the detector will be ready for enrichment with gadolinium.
On the theory side, additional simulations will be performed to clarify the dependence on progenitors and nuclear physics, and new features of neutrino signals in multi-D supernova explosions will be explored. The theory and experimental groups will continue to work together, including collaborating on joint publications already under discussion.

  • Research Products

    (20 results)

All 2017 Other

All Int'l Joint Research (6 results) Journal Article (2 results) (of which Peer Reviewed: 2 results,  Open Access: 2 results) Presentation (12 results) (of which Int'l Joint Research: 8 results,  Invited: 6 results)

  • [Int'l Joint Research] University Autonoma Madrid(スペイン)

    • Country Name
      SPAIN
    • Counterpart Institution
      University Autonoma Madrid
  • [Int'l Joint Research] University of British Columbia/University of Toronto/TRIUMF(カナダ)

    • Country Name
      CANADA
    • Counterpart Institution
      University of British Columbia/University of Toronto/TRIUMF
    • # of Other Institutions
      1
  • [Int'l Joint Research] Boston University/University of California, Irvine/California State University(米国)

    • Country Name
      U.S.A.
    • Counterpart Institution
      Boston University/University of California, Irvine/California State University
    • # of Other Institutions
      3
  • [Int'l Joint Research] Chonnam National University/GIST/Sungkyunkwan University(韓国)

    • Country Name
      KOREA (REP. OF KOREA)
    • Counterpart Institution
      Chonnam National University/GIST/Sungkyunkwan University
    • # of Other Institutions
      2
  • [Int'l Joint Research] Imperial College London/University of Sheffield/University of Liverpool(英国)

    • Country Name
      UNITED KINGDOM
    • Counterpart Institution
      Imperial College London/University of Sheffield/University of Liverpool
    • # of Other Institutions
      2
  • [Int'l Joint Research]

    • # of Other Countries
      3
  • [Journal Article] Determination of trace levels of uranium and thorium in high purity gadolinium sulfate using the ICP-MS with solid-phase chromatographic extraction resin2017

    • Author(s)
      Ito S、Takaku Y、Ikeda M、Kishimoto Y
    • Journal Title

      Progress of Theoretical and Experimental Physics

      Volume: 113H01 Pages: 43111

    • DOI

      10.1093/ptep/ptx145

    • Peer Reviewed / Open Access
  • [Journal Article] Supernova neutrinos in SK-Gd and other experiments2017

    • Author(s)
      Sekiya Hiroyuki
    • Journal Title

      Journal of Physics: Conference Series

      Volume: 888 Pages: 012041~012041

    • DOI

      10.1088/1742-6596/888/1/012041

    • Peer Reviewed / Open Access
  • [Presentation] ICP-MS measurement2017

    • Author(s)
      S. Ito
    • Organizer
      Physics of Fundamental Interactions
    • Int'l Joint Research / Invited
  • [Presentation] Results and prospects of underground physics research in Japan2017

    • Author(s)
      M. Nakahata
    • Organizer
      International Session-Conference of SNP PSD RAS
    • Int'l Joint Research / Invited
  • [Presentation] 30 years after SN1987A2017

    • Author(s)
      M. Nakahata
    • Organizer
      WIN2017
    • Int'l Joint Research / Invited
  • [Presentation] SK-Gd2017

    • Author(s)
      L. Marti
    • Organizer
      ICRC2017
    • Int'l Joint Research
  • [Presentation] RI background reduction for SK-Gd2017

    • Author(s)
      S. Ito
    • Organizer
      ICRC2017
    • Int'l Joint Research
  • [Presentation] SN1987A and its heritage2017

    • Author(s)
      M. Nakahata
    • Organizer
      Recent Development in Neutrino Physics and Astrophysics
    • Int'l Joint Research / Invited
  • [Presentation] Super-K Gd Project : DAQ and electronics update2017

    • Author(s)
      L. Marti
    • Organizer
      日本物理学会
  • [Presentation] SK-Gd プロジェクト:放射性不純物の測定2017

    • Author(s)
      S. Ito
    • Organizer
      日本物理学会
  • [Presentation] Observation of supernova neutrinos - past and now -2017

    • Author(s)
      M. Nakahata
    • Organizer
      Kavli IPMU 10th anniversary symposium
    • Int'l Joint Research / Invited
  • [Presentation] Neutrino Physics at Kamioka2017

    • Author(s)
      M. Nakahata
    • Organizer
      IBS conference on dark world
    • Int'l Joint Research / Invited
  • [Presentation] Super-K Gd プロジェクト:硫酸ガドリニウムに含まれる放射性不純物の低減2017

    • Author(s)
      Y. Kato
    • Organizer
      日本物理学会
  • [Presentation] SK-Gd のための放射生不純物の測定2017

    • Author(s)
      S. Ito
    • Organizer
      日本物理学会

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Published: 2019-12-27  

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