1. Comparing Large Underground Neutrino Detector Technologies: Liquid Argon, Liquid Scintillator, and Water Cherenkov John G. Learned University of Hawaii at ANT09, Hawaii A personal view, based upon experience with all three technologies. Good source papers: “Report on the Depth Requirements for a Massive Detector at Homestake”, arXiv:0907.4183v2; Large underground, liquid based detectors for astro-particle physics in Europe: scientific case and prospects”, arXiv:0705.0116v2

2. 13 August 2009John Learned @ ANT092 The three detectors in the LAGUNA study 1 vertical

3. 13 August 2009John Learned @ ANT093 Material Properties PropertyScintWaterArgon Z1,12 (1:1)1,16(2:1)40 X 0 /cm423620 p /gm/cm 3 0.8 – 1.01.01.39 Λ int /gm/cm 2 75.784.6117.2 Λ col /gm/cm 2 55.760.176.4 -dE/dx /gm/cm 2 2.301.991.52 n (optical)1.491.331.23 θms/√X 0 2.12.33.1 ~Cost /$/kg30.22 All three media are readily available in industrial quantities.

4. 13 August 2009John Learned @ ANT094 Water Cherenkov Cheapest target medium (but not negligible with filtering and dopants) Only route to megaton instruments Well proven technology (IMB, Kam, SK) Excellent for mu/e separation ~1 GeV. Electron scattering for solar nus. Threshold above ~4 MeV => no geonus or n-p captures. n detection needs Gd. No complex event topologies.

5. 13 August 2009John Learned @ ANT095 Liquid Scintillation Detectors Hi resolution, low threshold (<MeV) Technology well developed (50 years, plus Borexino, KamLAND and soon SNO+) Excellent for anti- neutrino detection by inverse beta decay. Liquid too expensive beyond ~100kT. New recognition: GeV neutrino physics too.

6. 13 August 2009John Learned @ ANT096 Liquid Argon TPC Detectors Bubble chamber-like imaging, detailed event topology, with few mm resolution. Developed over 30 years, and now being applied in 600 ton Icarus in Gran Sasso. No free protons for nucleon decay or inverse beta studies. Only detector for potential discrimination of e + from e - at neutrino factory.

7. 13 August 2009John Learned @ ANT097 Energy Range of Interest Large Underground Detectors Accelerator Neutrinos

8. 13 August 2009John Learned @ ANT098 Liquid Treatment All three require special facilities, all expensive and a bit hard to compare. do great job on first fill into superclean detectorLesson of past: do great job on first fill into superclean detector, have radon tight system, and do not have to recirculate much or at all.

9. 13 August 2009John Learned @ ANT099 Muon Rates for 100 kiloton Detectors at Homestake Depth/ftDepth/mweMuon Rate/ 2150m^2/sec 3002651616 1000880215 260023002.8 335029600.71 395034900.32 410036200.14 485042900.05

10. 13 August 2009John Learned @ ANT0910 Depth Requirements physicsAll depends upon physics goals… Also depends upon detector size… external backgrounds (eg. from muon showers in rock); worst for small instruments. Big detectors take hit near periphery. Great depth only needed for MeV measurements (geonus, low end of solar). PDK, accelerator studies, atm nus, SN, DSNB all can be done at much less depth… exact depth arguable depending upon technique and physics.

11. 13 August 2009John Learned @ ANT0911 Rough Graphical Representation of Depth Requirements Depth/ kmwe 0 H2OLSLAr 1 2 3 4 5 Long Baseline ~1GeV ν’s Nucleon Decay Supernova ~No Background Reactors Diffuse SN Neutrinos Geo-Neutrinos Many caveats required, but trend is correct... jgl opinion

12. 13 August 2009John Learned @ ANT0912 Nucleon Decay Predictions

13. 13 August 2009John Learned @ ANT0913 Nucleon Decay 43/2.25 1.0 x 10 35 The e+π 0 estimate for LENA is based upon new fitting methods. L Ar LS H 2 O

14. 13 August 2009John Learned @ ANT0914 Supernova Rates

15. 13 August 2009John Learned @ ANT0915 Diffuse Supernova Neutrino Background Better low energy atmospheric neutrino flux calculations needed.

16. 13 August 2009John Learned @ ANT0916 Physics Summary Comparison Chart PhysicsScintWaterArgon PDK e+pi01.0E35 yr 0.4E35 yr PDK nu-K0.4E35 yr0.2E350.6E35 Free p’sYes No Relic Sn nus <1/cm2~1/cm2No Solar nusYes PePYes Geo nus YesNoNo SN burst 2E42E56e4 E thresh <1 MeV ~4 MeV ~1 MeV Nucl Thresh 15 MeV 30 MeV 60 MeV Reactor Nus Yes Iff Gd No Reactor Hierarchy YesNoNo Reactor Theta13 YesNoNo Atm nus YesYesYes LBL e appear YesYesYes LBL e+/e- NoNoYes Indir WIMPsYes

17. 13 August 2009John Learned @ ANT0917 LAGUNA Seems to be on the map! Who will win? Plus Japan (HyperK). How will DUSEL fit into this picture?

18. 13 August 2009John Learned @ ANT0918 Bottom Line Each has strengths Long range: LAr wins for detailed neutrino physics in LBL, tho nice anytime Great sizes (megaton): H2O wins Low energies: Liquid Scint wins (particularly for geonus) Cost/vol hierarchy: LAr:LS:H2O Readiness: LS & H2O > LAr I like them all!!I like them all!!