ResponsetoRecommendationonMagnet

Sergio Bertolucci University of Bologna and INFN

Basedontheworkof:P.Bernardini,S.Biagi,C.Distefano,N.Mauri,M.Pozzato,P.Sala,A.Surdo,M.Tenti,F.Terranova,s.b.

Draft Recommendation

Basedonscientificconsiderations,theDUNENearDetectorConceptStudyrecommendtoanew-builddipolemagnetforthemulti-purposespectrometerdownstreamoftheLiquid-argonTPC(LArTPC).

24/03/18 2

ArgonCube Fiducial Volume

X(mm)

Z(mm) Z(mm)

Y(mm)

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The destiny of a muon

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6m

5m

ArgonCube

6m

5mArgonCube

z

x

z

y

Δy=0.5mcontained

contained

sideexitsideexit

enteringtrackingvolume

enteringtrackingvolumefrontlargeangle

frontlargeangle

ν

ν

Muon acceptance

24/03/18 5Muonmomentum(GeV/c) Muonmomentum(GeV/c)

acceptance

Similar conclusion in the draft recommendation

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Internal tracker

• Additionaltrackerinthespacebetweenyokeandcryostatstt

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A very crude muon ranger

Measurekineticenergyofescapingmuonsthroughrange•  10ironslabs(10cmthick)aroundACwithinterleavedtrackers(5cm)toconnectthetracksemergingfromAC

24/03/18 8µ ArgonCube

Ironslabs&tracker

Acceptance

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AllµfromACfiducialvol.StopinACStopinMuonRangerStopinYokeStopinCryoStopinCaloSTT

zoom

Kineticenergy(GeV)Kineticenergy(GeV)

} Stop+STT

Acceptance (Monte Carlo truth)

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Acceptance=(Stop+STT)/(allµfromACfiducialvol.)

Truekineticenergy(GeV)

Acceptance

Muon momentum reconstruction: µ stopping in AC (∼ 21%)

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Truekineticenergy(GeV) Truekineticenergy(GeV)

Recokineticene

rgy(GeV

)

µ stopping in the muon ranger (∼ 47%)

24/03/18 12Truekineticenergy(GeV)Truekineticenergy(GeV)

Recokineticene

rgy(GeV

)

Stopping in Yoke (∼ 5%)

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Truekineticenergy(GeV)Truekineticenergy(GeV)

Recokineticene

rgy(GeV

)

Stopping in the cryostat (∼ 0.7%)

24/03/18 14Truekineticenergy(GeV)Truekineticenergy(GeV)

Recokineticene

rgy(GeV

)

24/03/18 15Truekineticenergy(GeV)Truekineticenergy(GeV)

Recokineticene

rgy(GeV

)

Stopping in the Calorimeter (∼ 1.2%)

Going through the STT (∼ 10%)

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Truekineticenergy(GeV)Truekineticenergy(GeV)

Recokineticene

rgy(GeV

)

All together (∼ 85%)

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kineticenergy(GeV)Truekineticenergy(GeV)

Recokineticene

rgy(GeV

)

Acceptance

• Acceptance=(Stop+Stt)/(ACfiducialvol.)

•  Truekineticenergy• Recokineticenergy

24/03/18 18kineticenergy(GeV)

Acceptance

Overall resolution

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σE/E∼5.5%

Truekineticenergy/Recokineticenergy

… as a consequence

• Westronglydisagreewiththerecommendation• WeproposetocontinuethestudyoftheKLOEoption,untilproveninsufficientforthephysicsrequirementsofaHybridNearDetector

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Tothisextent,quotingAlfons:

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weintendtoprogressinthestudyofKLOE+STTintroducing:•  athin(≤1X0)LArtargetinsidethemagneticvolume•  thedigitizationofenergyandtimeresponseofthecalorimeter•  morerefinedreconstructionalgorithms•  …….

ν

LAr

CCeventsintheKLOEvolume,muons

Electrons: momentum resolution

24

GaussianFit:Mean ≅3.8%Sigma ≅ 5%

p:totalmomentum GENIE+Edep-Sim

𝜂= 𝑤𝑟𝑜𝑛𝑔 𝑠𝑖𝑔𝑛 𝑐ℎ𝑎𝑟𝑔𝑒𝑠/𝑎𝑙𝑙 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 𝑐ℎ𝑎𝑟𝑔𝑒𝑠 =0.18 %

Electrons: angular resolution

25

GaussianFitonθ:Mean ≅0mradSigma ≅0.8mrad

dip-angle

GENIE+Edep-Sim

π0Invariantmass

Δx<20cmandΔφ<5deg. Δx<30cmandΔφ<10deg.

Resolution stays to about 15% but we have a low energy tailThe tail is due to either ü  collinear gamma with a isolated hit from the debris of the photon shower picked up as a

shower or ü  gamma in calo with another gamma converted and either e- or e- rangeout

Resolution: 14.5% Resolution: 15.1%

5% below 50 MeV

ε(%)

Comparison with our scintillator normalized to the same active material thickness

)th.(calor.)th.(scint.

ε(scint.)ε(calor.)

⋅

Neutron efficiency

•  Stable for different run conditions

•  Very high efficiency w.r.t. the naive expectation ( ~ 10% @ 2 MeV thr.)

•  Epeak = 180 MeV

THANK YOU