Univ. of Hawaii: Steve Dye, John Learned , Shigenobu Matsuno, Marc Rosen,

1. Univ. of Hawaii: Steve Dye, John Learned, Shigenobu Matsuno, Marc Rosen, Michinari Sakai, Stefanie Smith, Gary Varner National Geospatial Intelligence-Agency (NGA): Shawn Usman, Alexander Spizler, James Georges III, Chris Mulliss, Glenn Jocher, Brian Dobbs, Daniel Bondy On the Road to Hanohano The mini-Time-Cube A Portable Directional Anti-Neutrino Detector Presentation at Neutrino Geosciences at Gran Sasso Laboratory, 7 October 2010 John Learned at Neutrino Geosciences 2010, Gran Sasso

2. On the Road to Hanohano • Need >10 KT scale underwater detector to do the mantle U/Th measurements, and begin real geoneutrino surveys. • Start with demonstrations of detection of reactors, first close up, then further away. • Importance of directionality understood. • Focus upon resolving positron production and neutron absorption locations. • Start with very small demonstration…. mTC • Work with those interested in reactor monitoring. • Geonus are a limiting background for reactor monitoring. • Must know if significant natural reactors should be present. John Learned at Neutrino Geosciences 2010, Gran Sasso

3. John Learned at Neutrino Geosciences 2010, Gran Sasso mTC Idea • Do imaging with fast timing, not optics (time reversal imaging). • Small portable 2.2 liter scintillating cube, • Boron doped plastic. • 4 x 6 MCP (x64 pixels each) fast pixel detectors on surrounding faces • Get neutrino directionality. • Reject noise on the fly. • ~10/day anti-neutrino interactions (inverse beta decay signature) from power reactor (San Onofre). 13 cm 2.2 liter

4. Virtues • Small size avoids gammas which smear resolution (Xo ~42 cm).... gammas mostly escape. • Fast pixel timing (<100ps) and fast processing of waveforms rejects background in real time. • No need for shielding (unlike other detectors). • Feasible even in high noise environment, near reactor vessel, at surface (eg. in a truck). • Neutrino directionality via precision positron production and neutron absorption locations. John Learned at Neutrino Geosciences 2010, Gran Sasso

5. John Learned at Neutrino Geosciences 2010, Gran Sasso Snapshot of the Fermat Surface for a Single Muon-likeTrack Track Huygens wavelets Incoherent sum coincident with Cherenkov surface: Not polarized! J. Learned arXiv:0902.4009v1

6. John Learned at Neutrino Geosciences 2010, Gran Sasso Hiroko Watanabe (Workshop Towards Neutrino Technologies 2009)

7. John Learned at Neutrino Geosciences 2010, Gran Sasso 2.α & triton stop ~immediately (mm). 2.40 cm γ radiation length. Hiroko Watanabe (Workshop Towards Neutrino Technologies 2009)

8. John Learned at Neutrino Geosciences 2010, Gran Sasso Hiroko Watanabe (Workshop Towards Neutrino Technologies 2009)

9. John Learned at Neutrino Geosciences 2010, Gran Sasso KamLAND resolution Hiroko Watanabe (Workshop Towards Neutrino Technologies 2009)

10. John Learned at Neutrino Geosciences 2010, Gran Sasso Study using KamLAND LS and Resolution Hiroko Watanabe (Workshop Towards Neutrino Technologies 2009) We can, in principle, do much better with mTC. Much further gain possible if can sense first neutron elastic scattering location.

11. John Learned at Neutrino Geosciences 2010, Gran Sasso First version will use B loaded plastic scintillator First casting with bubble from Eljen

12. John Learned at Neutrino Geosciences 2010, Gran Sasso Neutron Capture Cross Section

13. John Learned at Neutrino Geosciences 2010, Gran Sasso Mini-TimeCube + PMTs and Readout Electronics (Portable) Volume ~ (2 ft)3 Weight < 30 kg ~43cm (<1’6”) Plus separate processing electronics box.

14. John Learned at Neutrino Geosciences 2010, Gran Sasso Photonis 8 x 8 Multi-channel plate PMT

15. The Photo-Sensor: Photonis XP85012 (64 channel MCP) John Learned at Neutrino Geosciences 2010, Gran Sasso

16. John Learned at Neutrino Geosciences 2010, Gran Sasso Evaluation MCP Signal Jean-Francois Genat, ANT Workshop, August 13, 2009 408nm laser, 100 Photo-Electrons Conclusion: Gain: 40mV/100PE ~ 0.4mV/PE (25m) at 2100 V 5mV/100PE ~ 50 V/PE (10m) at 2500V 10m longer trailing edge Seems that rise time does NOT depend upon the amplitude => We choose 25μm pore size Under development

17. John Learned at Neutrino Geosciences 2010, Gran Sasso Impulse Dark Noise vs HV Conclusion: At optimum efficiency (25m 2000V, 10m 2400V), dark counts rates are: 25Hz (25m)‏, 20Hz (10m)‏ per pixel

18. Mini-TimeCube Sensitivity(13cm^3 cube with 24 MCP's) • Rough cost => $300K (includes electronics, mostly MCP tubes) • Rate => ~10 anti-neutrino events/day (25m from 3.3GW reactor) • Photo sensitive Area => 75% coverage • Pixel count => 1536 • Typical reactor anti-neutrino => several PE/pixel • 100ps MCP time resolution => 20mm spatial resolution. • 2 ns scintillator decay constant => 120 PE/MeV in first 200ps. • How well can we do vertex reconstruction from 1st photon hits? => TBD, mm probable John Learned at Neutrino Geosciences 2010, Gran Sasso

19. John Learned at Neutrino Geosciences 2010, Gran Sasso Neutrino Vertex Resolution • KamLAND: center of ionization for e+ and n capture => >10 cm • 120 PE/MeV on Fermat surface => ~20mm/sqrt(120*E/MeV) = 1.3 mm • (2 MeV anti-neutrino). • Neutrino Vertex Resolution => Several mm -> directionality • Problem: exponential decay of scintillator. • Solution: employ first hits • In actuality do full liklihood analysis. Initial promising results from NGA collaborators employing medical imaging like algorithms.

20. John Learned at Neutrino Geosciences 2010, Gran Sasso Geant4: Radiation Length in LS Neutrino interaction point Mini-TimeCube Gamma from neutron inelastic capture 2m Gamma from positron annihilation Conclusion: Gamma from positron annihilation leaves detector without interaction.

21. Examples of PMT Read-outs Developed by IDL, Hawaii (Gary Varner) Fast waveform digitizer for the Photonis MCP is currently under development evolving from existing technology used in BELLE, BESS, ANITA. Length beyond photo-sensor will be ~125mm. One module per MCP. John Learned at Neutrino Geosciences 2010, Gran Sasso

22. Data Acquisition System (DAQ) Based on cPCI Format cPCI CPU cPCI crate x1 Data processing card x3 (= 24 PMTs) 3Gbs fiber link John Learned at Neutrino Geosciences 2010, Gran Sasso

23. Mini Time Cube Based On 13cm3 Boron Loaded Plastic Scintillator 38 cm MTC with read-out electronics on one face MTC fully populated with read-out electronics DAQ fits upper case Detector fits lower case MTC within 2ft3 honeycomb enclosure Stackable transport cases John Learned at Neutrino Geosciences 2010, Gran Sasso

24. John Learned at Neutrino Geosciences 2010, Gran Sasso Noise Rate • Refer to CORMORAD talk given by Marco Battaglieri (Genoa) at Trieste. • Prototype segmented detector of square logs of NE110 plastic scintillator, 3 inch PMTs on ends, 40x30x30 cm^3 total volume. • No shielding (similar to MTC) => big background • CORMORAD noise rate near Romanian reactor: => R = ~120 Hz (single) => 2 x R^2 x tau = ~10 Hz (two hits in time window tau = 330us) • Similar numbers from 2 expts at San Onofre • MTC noise rate <= 1/(30 x 10) x CORM. < few Hz => good enough for real-time background analysis & rejection ”A proposal for a high segmented power reactor antineutrino detector”, Marco Battaglieri, July 13~17, 2009, Workshop Towards Neutrino Technologies”

25. John Learned at Neutrino Geosciences 2010, Gran Sasso Items for Further Study • Backgrounds => stopping muon, decay processes, random internal/external gamma (from reactor), thermal neutron... • Solid scintillators => boron loaded plastic from Eljen Technology, initial build • Liquid scintillators => find shortest n capture time, optimum Li loading... later (1 yr) • Pulse shape discrimination for neutron capture? • Can we do anything with neutron elastic scattering? First scatter importance. • GEANT Simulation of mini-Time Cube in progress (some troubles with neutron propagation in program). • Careful evaluation of angular resolution with full analysis of waveforms.

26. Summary and Future • Building tiny portable unshielded neutrino detector which can measure useful rate near power reactor, and get some neutrino directionality. • Parts ordered, begin assembly this year, take to reactor in 2011. • For economical construction need LAPPDs (Chicago/ANL) • Next version ~1m^3, able to measure reactors outside the fence from small van. • KANU ~12m^3, 6m dia, out to 6km and 300m depth in water. • Future, stacks of same in shipping containers. • Reactor monitoring, but also moving towards Hanohano geoneutrinos and other science! John Learned at Neutrino Geosciences 2010, Gran Sasso