2019 Fiscal Year Annual Research Report
Enhancing the direct search for dark matter in the XENON nT experiment with a water Cerenkov neutron detector
| Project/Area Number |
19H00675
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MARTENS Kai 東京大学, カブリ数物連携宇宙研究機構, 准教授 (20535025)
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| Co-Investigator(Kenkyū-buntansha) |
平出 克樹 東京大学, 宇宙線研究所, 特任助教 (10584261)
竹田 敦 東京大学, 宇宙線研究所, 准教授 (40401286)
伊藤 好孝 名古屋大学, 宇宙地球環境研究所, 教授 (50272521)
身内 賢太朗 神戸大学, 理学研究科, 准教授 (80362440)
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| Project Period (FY) |
2019-04-01 – 2023-03-31
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| Keywords | neutron veto / dark matter / direct detection / water Cherenkov / gadolinium sulfate |
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| Outline of Annual Research Achievements |
During FY 2019 our Japanese neutron veto group for the XENONnT dark matter direct detection experiment at LNGS in Italy made good progress under this grant:
Our expert debugged the new neutron veto FADC electronics at LNGS and helped testing the neutron veto photomultipliers there.
We upgraded a commercial spectrophotometer and developed the measurment protocol to reliably measure Super-Kamiokande (SK) grade water transparency with it. It is an important tool to be used at LNGS to monitor the neutron veto's water transparency and help identify potential problems should they arise. It already played an important role in selecting suppliers for the Gd-sulfate we need. Our SK-Gd based procedures for corrosion prevention in water Cherenkov detectors are used at LNGS for XENONnT to enable implementation of our neutron veto technology.
Kobe University developed the light injection system for neutron veto calibration. Having been tested in Kobe this system is on its way to LNGS for installation. Designing this system also laid the foundations for nVeto data analysis here in Japan. Nagoya University drove our verification program for materials used in the detector: materials found incompatible with Gd-sulfate water had to be replaced. With the company that provided the band-pass system that treats Gd-sulfate water at EGADS we developed the neutron veto system for XENONnT.
In summary our neutron veto effort supported by this grant is well on track and we are in a position to start analysis of nVeto calibration and physics data.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
There were slight delays in other parts of the experiment that delayed the neutron veto installation. These have since been made worth by the advent of COVID-19. None of this will ultimately interfere with the full implementation of our neutron veto plans.
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| Strategy for Future Research Activity |
We will continue implementing our plans as foreseen as soon as the COVID-19 situations allows. As our plan is well attuned to the overall needs and schedule of the XENONnT discovery machine, we see no reason to change our well laid plans.
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