Small Neutrino Detectors -Purpose of small neutrino detectors -Beams at Fermilab -Design Criteria -Three Sizes and their Neutrino Rates Acknowledgement:

Hans Jostlein, May 13th 2006, LAr group mtg

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Small Neutrino Detectors

-Purpose of small neutrino detectors-Beams at Fermilab-Design Criteria-Three Sizes and their Neutrino Rates

Acknowledgement:Material stolen from many sources


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Purpose of Small Neutrino Detectors

Physics development using existing technology Record complete neutrino interactions ( and e)

in the presence of cosmic rays Establish physics collaboration by:

Developing event identification Developing reconstruction Developing analysis

Measure interactions in the quasi-elastic and resonance region (?)

Where to find 2 GeV electrons ?


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Requirements to do the Neutrino Study

• -see real neutrino interactions in Liquid Argon• -sufficient containment (define !)• -Sufficient rate (define!)• -measure Nu-e from nu-mu discrimination with actual events• -of the right energy !• -measure overall detection efficiency (e.g. acceptable y-

range)


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Neutrino Beams at Fermilab

• -Two beams (from Booster and from Main Injector• -Hot Beams ! (Even at the surface)• -Electron and Muon Neutrinos in comparable numbers• -Can match spectra rather well to future far detectors


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Neutrino Beams at Fermilab,continued

• -Rates were calculated for NOVA originally• -some questions of geometry are being sorted out• -will use rates that are a little too high, we expect• -experts are calculating real spectra very soon


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Neutrino Beams at Fermilab


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Electron Neutrinos in MINOS Surface Building

NuMI is presently providing ~2E20 POT per year.

From the NOvA Proposal March 15, 2005

e CC events / 50 MeV

The charged current e event spectrum in the MINOS surface building. The e event spectrum peaks just below 2 GeV. There are ~2,000 e events shown here for 6.5E20 POT and the 20.4 ton fiducial mass NOvA near detector.


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Muon Neutrinos in MINOS Surface Building

The peak at ~2.8 GeV is from Kaon decay.

From the NOvA Proposal March 15, 2005

CC events / 50 MeV


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Event Containment

For the rate calculation (later in the talk)we will use a required event length of

1.5 m from the vertex.This is 11 radiation length in liquid Argon.

We must catch all relevant event topological features.

Maybe 50 cm is enough ?This would increase the “target mass” substantially.

See next slide.


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Event Containment

50 cm

Event Containment –how much depth ?


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Detector Sizes Considered:“5 m Drift Detector


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Detector Sizes Considered:“ 3 Meter Detector”


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Rates are per year , ME tune of the NUMI beam, for: 2.00E+20 Protons on TargetPi= 3.14159265

Device 5m drift 3 Meter 130 ton 1 kton 3 ktonCryostat Diameter [m] 0.85 3 4 10 12Cryostat Argon level Height [m] 5 4 8 10 20Nominal volume [m 3̂) 2.837 28.3 100.5 785.4 2261.9Nominal Argon Mass [ton] 3.972 39.6 140.7 1099.6 3166.7Active Argon Mass (I.e. within the TPC) [ton] 1.430 18.1Target volume (ton) guessed 0.5 4.8 50 600 2000

Xverse dim too small?Cosmic Ray Rate (use rate of 100 /m^2 s) [Hz] 425 1200 3200 10000 24000

NUMI Surface building: Per ton: Per detector:Nu-mu events /year 430 215 2064 21495 257942 859808Nu-e events/year 24 12 115 1201 14411 48035

Device can see nu-mu events at NUMI building yes yes yes yes yesDevice can see nu-e events at NUMI building no yes yes yes yesDevice can study nu-mu versus nu-e at NUMI building no yes yes yes yes

Device can measure nu-mu cross sections at NUMI no yes yes yes yesDevice can measure nu-e cross sections at NUMI no maybe yes yes yes

Location 1.5 as per NOVA Per ton: Per detector:Nu-mu events/year at site 1.5 77511 38756 372054 3875566 Doesn't fit Doesn't fitNu-e events/year at site 1.5 1444 722 6930 72191 Doesn't fit Doesn't fit

Device can see nu-mu events at location 1.5 yes yes yes Doesn't fit Doesn't fitDevice can see nu-e events at location 1.5 yes yes yes Doesn't fit Doesn't fitDevice can study nu-mu versus nu-e at location 1.5 maybe yes yes Doesn't fit Doesn't fit

Xverse dim too small?Device can measure nu-mu cross sections at loc. 1.5 maybe yes yes Doesn't fit Doesn't fitDevice can measure nu-e cross sections at loc. 1.5 maybe yes yes Doesn't fit Doesn't fit


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Conclusions

•-Crucial Need for real neutrino interactions in Argon•-A surface detector of about 30 ton total mass is • the minimum requirement•-smaller detector below ground would suffice, but may be the more difficult project

Documents

Small Neutrino Detectors -Purpose of small neutrino detectors -Beams at Fermilab -Design Criteria -Three Sizes and their Neutrino Rates Acknowledgement: