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Steve Dye, John Learned , Shigenobu Matsuno, Marc Rosen, Michinari Sakai, Stefanie Smith, Gary Varner, and students Univ. of Hawaii : Plus some other colleagues elsewhere. The mini-Time-Cube A Portable Directional Anti-Neutrino Detector. Presentation at ANT11, Philadelphia, 10 October 2011.

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Steve dye john learned shigenobu matsuno marc rosen

Steve Dye, John Learned, Shigenobu Matsuno, Marc Rosen,

Michinari Sakai, Stefanie Smith, Gary Varner, and students

Univ. of Hawaii:

Plus some other colleagues elsewhere

The mini-Time-Cube

A Portable Directional Anti-Neutrino Detector

Presentation at ANT11, Philadelphia, 10 October 2011


Mtc idea

John Learned at ANT11 in Philadelphia

mTC Idea

  • Do imaging with (100 ps) 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


Mtc virtues

John Learned at ANT11 in Philadelphia

mTC Virtues

  • Small size avoids positron annihilation gammas which

  • smear resolution (Xo ~42 cm).... gammas mostly escape,

  • permitting precise positron creation point location.

  • Fast pixel timing (<100ps) and fast pipeline processing of

  • waveforms rejects background in real time.

  • Having many pixels plus use of first-in light permits mm precision in vertex locations.

  • Neutrino directionality via precision positron production

  • and neutron absorption locations.

  • No need for shielding (unlike other detectors).

  • Feasible even in high noise environment, near reactor

  • vessel, at surface (eg. in a truck).


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia

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


Time reversal image reconstruction

John Learned at ANT11 in Philadelphia

Time Reversal Image Reconstruction

Figure by Mich Sakai


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia

Directional Measurement

Hiroko Watanabe (Workshop Towards Neutrino Technologies 2009)


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia

Reactions in the Liquid Scintillator

2.α & triton stop ~immediately (mm).

2.40 cm γ radiation length.

Hiroko Watanabe (Workshop Towards Neutrino Technologies 2009)


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia

Neutrino Capture Nucleus Choices

Hiroko Watanabe (Workshop Towards Neutrino Technologies 2009)


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia

KamLAND Calculations

KamLAND resolution

Hiroko Watanabe (Workshop Towards Neutrino Technologies 2009)


Study using kamland ls and resolution

John Learned at ANT11 in Philadelphia

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.


Gammas usually leave mtc

John Learned at ANT11 in Philadelphia

Gammas Usually Leave mTC

Neutrino interaction point

Mini-TimeCube

Gamma from neutron inelastic capture

2m

Gamma from positron annihilation

Conclusion: Gammas from positron annihilation leave mTC detector without interaction,

thus not confusing vertex resolution.


Inverse beta kinematics

John Learned at ANT11 in Philadelphia

Average over reactor spectum

Inverse Beta Kinematics

Neutron only gets

15.75 keV mean,

most to positron.

Trickier than you may realize...

The positron gets the kinetic energy and the neutron gets the momentum.

Plots by Stefanie Smith


We can select an event sample with good pointing

John Learned at ANT11 in Philadelphia

We can select an event sample with good pointing

Early neutrino captures point better

Most early captures out ~ cm distance

Early n captures: strong correlation

between neutron and positron

scattering angles.

Lower energies a little better


Some tentative conclusions on neutrino direction determination in mtc

John Learned at ANT11 in Philadelphia

Some tentative conclusions on neutrino direction determination in mTC

  • Get interaction vertex to ~1 mm and positron directions using fast timing and first hit reconstruction.

  • Proton scatters by neutron would be most useful, but probably not enough light to reconstruct.

  • Neutron capture location determined best with 6 Lithium by detecting alpha and triton.

  • Can select golden events for best pointing. How good still TBD.

  • Maximally utilize full information, employing full MaxL, yet to be done.

  • We are exploring use of a neural network.


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia


Fitting the positron streak

John Learned at ANT11 in Philadelphia

Fitting the Positron Streak


First mtc version using b loaded plastic scintillator

John Learned at ANT11 in Philadelphia

First mTC version using B loaded plastic scintillator

First casting with bubble from Eljen


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia

Mini-TimeCube + PMTs and Readout Electronics (Portable)

Volume ~ (2 ft)3

Weight < 30 kg

~43cm (<1’6”)

Plus separate processing electronics box.


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia

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.


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia

Data Acquisition System (DAQ) Based on cPCI Format

MCP PMT and Digitizer

Internet

x1

cPCI CPU

3Gbs fiber link x 8

x3 (= 24 PMTs)

Data processing card (x3)

cPCI crate


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia

Mini Time Cube: 13cm3 Boron Loaded Plastic Scintillator

38 cm

MTC with read-out electronics on one face

MTC fully populated with read-out electronics

Computer and DAQ

fits upper case

Detector and power supplies in lower case

MTC within 2ft3 anodized Al enclosure

Stackable transport cases


The mtc being assembled

John Learned at ANT11 in Philadelphia

The mTC Being Assembled

Gas and RF tight box

Rosen design

UV laser illumination


Picosecond calibration laser system

John Learned at ANT11 in Philadelphia

Picosecond Calibration Laser System

Matsuno/Rosen


Estimate real world unshielded noise rate from italian cormorad experiment

John Learned at ANT11 in Philadelphia

Estimate Real World Unshielded Noise Rate from Italian CORMORAD Experiment

  • Refer to CORMORAD talk given by Marco Battaglieri (Genoa) at Trieste 2009.

  • Prototype segmented detector of square logs of NE110 plastic scintillator, 3 inch PMTs on ends, 40x30x30 cm^3 total volume.

  • No shielding => big background, outside containment building.

  • CORMORAD noise rate near Romanian reactor:

    => R = ~120 Hz (single)

    => 2 x R^2 x τ = ~10 Hz

    (for two hits in time window τ = 330μs)

  • mTC noise rate implications:

    • ≤ 1/30 vol. x 1/10 time resol. x CORM. rate

      = few Hz in mTC

  • Similar numbers from 2 expts at San Onofre

  • (info: LLNL/Sandia group and Juan Collar)

    » good enough for real-time background analysis & rejection, with no shielding

    Software rejection needed ~10^5 (< KamLAND)

”A proposal for a high segmented power reactor antineutrino detector”, Marco Battaglieri, July 13~17, 2009, Workshop Towards Neutrino Technologies”


Mini timecube sensitivity 13cm 3 cube with 24 mcp s

John Learned at ANT11 in Philadelphia

Mini-TimeCube Sensitivity(13cm^3 cube with 24 MCP's)

  • Photo sensitive Area75% coverage of 1,014 cm^2

  • Pixel count1536 (= 64/pmt * 4 pmt/side * 6 sides)

  • Typical reactor anti-neutrino several PE/pixel

  • 100ps MCP time resolution 2 mm spatial resolution/hit

  • 2 ns scintdecay constant120 PE/MeV in first 200ps.

  • Vertex recon. with 1st hits ~1 mm level.

  • Rate~10 anti-neutrino events/day (25m from 3.3GW reactor)

  • Rough cost~$300K (includes electronics, mostly MCP tubes)

  • much less with future LAPPDs


Summary of what we can measure

John Learned at ANT11 in Philadelphia

Summary of what we can measure

  • Neutrino energy, via positron energy

  • Positron vertex and direction.

  • Neutron capture point & direction from vertex to capture point.

  • Enough information to get neutrino direction along a cone and maybe better using full constraints.

  • Possibly more: total neutron kinetic energy.

  • Probably too difficult: location of first n scatter.

  • Conclusion: We can do better than anyone has in the past. How much better remains to be demonstrated.


Mtc study and plans

John Learned at ANT11 in Philadelphia

mTC Study and Plans

  • Backgroundsstopping muon, decay processes, random internal/external

  • gamma (from reactor), thermal neutron...

  • Solid scintillatorsboron loaded plastic from Eljen for initial build, not ideal

  • Liquid scintillatorsshort n capture time, best n absorb vertex: 6Li loading... soon

  • Pulse shape discrimination for neutron capture?

  • Can we do anything with neutron elastic scattering? First scatter important but tough.

  • GEANT Simulation of mini-Time Cube in progress…. Understanding tricks of simplekinematics and determining if golden sample identifiable.

  • Careful evaluation of angular resolution with full analysis of waveforms.

  • Time to activation waiting on electronics construction.

  • mTC operating in Lab early 2012, and take to reactor ASAP thereafter.


On the road to short and long range nuclear reactor monitoring and other physics

John Learned at ANT11 in Philadelphia

On the Road to Short and Long Range Nuclear Reactor Monitoring and Other Physics

2 liters

mTC

  • 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.

  • Build ~1 m^3 detector, range to ~200m

  • Possible detailed search for short range oscillations

  • Place a number of modules in shipping container

  • and monitor out to few km

1 m^3

TC

Truck size

200 m


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia


Photonis 8 x 8 multi channel plate pmt

John Learned at ANT11 in Philadelphia

Photonis 8 x 8 Multi-channel plate PMT


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia

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


The photo sensor photonis xp85012 64 channel mcp

John Learned at ANT11 in Philadelphia

The Photo-Sensor: Photonis XP85012 (64 channel MCP)


Steve dye john learned shigenobu matsuno marc rosen

John Learned at ANT11 in Philadelphia

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


Neutron capture cross section

John Learned at ANT11 in Philadelphia

Neutron Capture Cross Section


Neutrino vertex resolution

John Learned at ANT11 in Philadelphia

Neutrino Vertex Resolution

  • KamLAND example: center of ionization for e+ and n capture >10 cm… not useful for present concerns.

  • 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.


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