LENS: Science Scope and Future Development Stages LENS - - PowerPoint PPT Presentation

LENS Collaboration

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LENS: Science Scope and Development Stages

Collaboration

VT - R. Bruce Vogelaar, Mark Pitt, Camillo Mariani, S. Derek Rountree, Laszlo Papp, Zachary Yokley, Tristan Wright, Joey Heimburger, Lillie Robinson LSU - Jeff Blackmon, Charles Rasco, Liudmyla Afanasieva, Kevin Macon, Matt Amrit BNL - Minfang Yeh, Lianming Hu NCCU - Diane Markoff, Israel Esan UNC - Art Champagne HBNI, India – Vivek Datar NSF supported R B Vogelaar Jun 9, 2014

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Advantages

• Measures neutrino energy with low threshold
• Taggable against internal & external backgrounds

Solved (being demonstrated with mini-LENS)

• Lattice construction
• Scintillator Loading with In

Remaining Challenges

• Cross section uncertainty
• Quenching effects
• Size required for ‘precision’
• …never turn down more light….

25 years ago, with current design, THIS would have been the experiment do to…

Why 115In?

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the 115I charged current neutrino detector manifested in a “Scintillation Lattice” detector (Conceived by the late Raju Raghavan)

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trigger tag (false)

trigger tag (neutrino event) prompt e1

Pulse vs Time Δt Ee1

single In beta

random correlated

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Internal ‘false tags’ due to In dominate External ‘false tags’ eliminated by shielding

A1: 1 In beta (with Bremsstrehlung) A2: 1 In beta (to 497 plus gamma) B: 2 In betas (with Brem.) C: 3 In betas

NOTE: all the ‘tag’ cells must fire within a 10 ns window (Δtw)

What makes a ‘trigger tag’?

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LENS Collaboration

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7 Configuration: C0 C1 C3 C5 # XP3330: 28 120 120 112 # 9821B: 6 78 150 Wall Index: 1.35 1.0/1.257 1.0/1.257 1.0/1.257 Scint: LAB 1% InLAB 1% InLAB 1%(10%) InLAB Figure 1 Staged configurations for micro-LENS (C0) and mini-LENS (C1,3,5). The yellow squares represent Photonis XP3330 tubes, which have poor timing characteristics. The blue squares represent Electron Tubes 9821B PMTs. See supporting text for an explanation of this staged approach.

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Traditional 3% design:

• 5x5x5 m central detector
• 10% by mass 115In
• 5 years of data

Can 115In be used to measure the “complete” solar neutrino spectrum to “1%”?

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quenching impact on pp ν

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quenching impact on pp ν

Peak A: Single Photo-Electric interaction (about 1% of the time), slightly quenched ¡ Peak B: Compton, followed by Photo-Electric ¡ Peak C: two Comptons, followed by Photo-Electric ¡ Everything else: combination of Compton and Photo-Electric ¡ Notice how requiring 3 ‘hits’ removes Peaks A & B ¡

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quenching impact on pp ν

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Calibration

• Normalize to 7Be results of Borexino
• Neutrino source at detector
• “LENS-Cal” per Raghavan
• Mini-LENS next to reactor with short lived

neutrino source ‘rabbit’ into core…

• Serious challenge…

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Other Scintillation Lattice applications….

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Figure 20: Expected signal in the SNO+ detector for enriched 150Nd and a 150 meV Majorana mass.. Note (in addition to the 8Be neutrino background) the broad peak caused by untagged internal 208Tl decays which obscures the 0nuββ peak. The modular design of the LENS detector affords a veto mechanism due to its ability to discriminate between cascade (beta + high e gamma) events such as the Tl

• background. (ZUB07)

¡

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