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Mark Vagins Kavli IPMU, University of Tokyo

Gadolinium Option for Hyper-K: World-class Water. Mark Vagins Kavli IPMU, University of Tokyo. Open Meeting for the Hyper-Kamiokande Project Kashiwa August 23, 2012. Theorist John Beacom and I wrote the original GADZOOKS! ( G adolinium A ntineutrino D etector Z ealously

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Mark Vagins Kavli IPMU, University of Tokyo

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  1. Gadolinium Option for Hyper-K:World-class Water Mark Vagins Kavli IPMU, University of Tokyo Open Meeting for the Hyper-Kamiokande Project Kashiwa August 23, 2012

  2. Theorist John Beacom and I wrote the original GADZOOKS! (Gadolinium Antineutrino Detector Zealously Outperforming Old Kamiokande, Super!) paper. It proposed loading big WC detectors, specifically Super-K, with water soluble gadolinium, and evaluated the physics potential and backgrounds of a giant antineutrino detector. [Beacom and Vagins, Phys. Rev. Lett., 93:171101, 2004]

  3. ne can be identified by delayed coincidence. Basically, we said, “Let’s add 0.2% of a water soluble gadolinium compound to Super-K!” Possibility 1: 10% or less n+p→d + g n g ne 2.2 MeV g-ray p p Gd e+ g Possibility 2: 90% or more n+Gd →~8MeV g DT = ~30 msec Positron and gamma ray vertices are within ~50cm.

  4. Gadolinium in Hyper-Kamiokande Originally conceived as a Super-K upgrade, the true power of gadolinium loading would be uniquely realized in Hyper-K: With Gd, proton decay backgrounds would be reduced between 50% and 80%, which will become important at the Mton*year exposure level, particularly for p  e+ + p0. o(100) DSNB events/year (+ mini-bursts) would provide spectral information, yielding the average SN’s energetics, as well as the universe’s supernova history and dark SN rate. [S. Horiuchi] In addition to other benefits [Y. Koshio], in the case of a galactic supernova, neutron tagging would allow certain isolation of the early neutronization signal. Only HK with Gd can fully resolve this signal at the galactic center. A Gd-loaded HK provides a strong new WIMP channel. [C. Rott] GADZOOKS! is already on the Japan CRC roadmap. [N. Kanda]

  5. Now, to makegadolinum loading work, we will have to: Dissolve the gadolinium sulfate in the water Easy and fast (pH control) Remove the gadolinium efficiently and completely when desired  Also easy and fast (pH control) Keep pure water pure yet retain gadolinium in solution  The tricky part; need a selective Gd filtration system

  6. The Essential Magic Trick → We must keep the water in any Gd-loaded detector perfectly clean… without removing the dissolved Gd. → I’ve developed a new technology: “Molecular Band-Pass Filtration” Staged nanofiltration selectivelyretains Gd while removing impurities. Amazingly, the darn thing works! This technology will support a variety of applications, such as: → Supernova neutrino and proton decay searches → Remote detection of clandestine fissile material production → Efficient generation of clean drinking water without electricity

  7. Electrical Band-Pass Filter

  8. Molecular Band-Pass Filter Gd2(SO4)3 (NF Reject) Gd2(SO4)3 plus smaller impurities (UF Product) Pure water plus Gd2(SO4)3 Ultrafilter Nanofilter Impurities larger than Gd2(SO4)3 (UF Reject flushed periodically ) Impurities smaller than Gd2(SO4)3 (NF Product) Reverse Osmosis Pure water (RO product) plus Gd2(SO4)3 Larger and smallerimpurities to drain (UF Flush + RO Reject)

  9. UF Product NF Reject

  10. Band-Pass Window

  11. Over the last nine years there have been a large number of Gd-related R&D studies carried out in the US and Japan:

  12. EGADS (initial Japanese funding = $4,300,000) Super-Kamiokande EGADS Facility Super-K Water system EGADS Hall (2500 m^3) Now,ICRR and IPMU (with UCI and OkayamaU) have built a dedicated 200-ton Gd demonstrator project: EGADS – Evaluating Gadolinium’s Action on Detector Systems. 12/2009 2/2010 6/2010 12/2010 By next year, EGADS will have shown conclusively whether or not gadolinium loading of Super-Kamiokande will be safe and effective. If so, this is the likely future of all water Cherenkov detectors.

  13. ;. 200-ton WaterCherenkov Detector (240 50-cm PMT’s) 15-ton Gadolinium Pre-treatment Mixing Tank Selective Water+Gd Filtration System Hall E and EGADS 11/2011

  14. Cherenkov Light Remaining at 20 m (200-ton tank) Within a few months of turning on the system our pure “band-pass” water was as good as Super-K's ultrapure water after 15 years of tuning and adjustments! We then introduced gadolinium into the system…

  15. Studies continue, but we have already achieved stable light levels of 66% at 20 meters with fully Gd-loaded water. This should be compared to a range of 71%79% for “perfect” pure water in SK-IV.  No detected Gd loss after >100 complete turnovers. Stable running ~66% light @ 1900 ppm with Amberjet4400, ~63% without

  16. Multi-messenger Supernova Astronomy: X-ray, g-ray, Optical, Infrared, GW, andNeutrino Approved - June 2012 ~$1.6M for EGADS/IPMU

  17. Japan-based Organo has had a near monopoly on major Kamioka water systems for decades  Pluses: They are local and established, can respond quickly  Minuses: Monopoly can lead to high costs, no Gd experience • US-based South Coast Water has developed and built many water systems for physics experiments in the US and Japan Pluses: Lower cost, Gd experience, 35-year partnership  Minuses: Main factory is far from Japan, language issues

  18. South Coast Water and its CEO Roy Hall got the contract for EGADS’ main (Gd filtering) water system. They previously built the pure water systems for: IMB, Milagro, E261a/b (the 1994 KEK beam test experiment), K2K’s 1KT detector, and LUX They also operate the fresh air system for SK/XMASS/EGADS. SCW’s ~1000 active accounts include the US Navy, hospitals, semiconductor fabrication plants, and even a few movie stars.

  19. Has offered to build a permanentbranch office in Japan to provideservice and support to Hyper-K Will likely respond positively to serious price competition

  20. Industrial water input SCW’s preliminary design for a Hyper-K water filling system Uranium Removal,DI and UV Pre-treatment and RO To tank: 364 tons/hr = 190 ktons/month Chiller and Degas

  21. SCW’s preliminary design for a modular (one tank) Hyper-K-water recirculation system From detector via RO Uranium Removal and DI Back todetector 730 tons/hr = 526 ktons/month 0.1 mm and 1.0 mm filters This design is intended to be easily upgradable for handling gadolinium

  22. We intend to put together a truly world-class water system for Hyper-Kamiokande.  Let’s work together to get it done! 

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