ND Status & PlanKam-Biu Luk

UC Berkeley and LBNLAlfons Weber

Oxford and STFC/RAL/CERN

CERN, 1 Feb 2018

Importance of Nuclear Effect•  Nuclear effects (Duyang)–  Bias reconstruction of neutrino energy–  Background to ν-e elastic scattering–  Affect low-ν measurement

•  Nuclear effects of Ar are more serious than those of CH2

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25-t LAr5-t STT

•  Importance to have a hybrid near detector with different target materials.

ND Options•  Agreement–  A non-magnetized LAr TPC followed by a low-mass argon-based

magnetic spectrometer that improves acceptance of muons from LAr and provides another independent data sample.

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LAr TPCbeam Low-mass trackerin a magnetic volume

Surrounded byECal and muondetector

•  Unsettled issues–  Magnet: KLOE solenoid or a new dipole magnet–  Low-mass tracker: straw-tubes or HP gaseous Ar TPC–  Four possible configurations that the LAr TPC can combine with

•  KLOE + STT•  KLOE + HPgAr TPC•  Dipole + STT (documented in CDR) •  Dipole + HPgAr TPC

Additional Options•  3DST

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LAr TPCbeam Low-mass trackerin a magnetic volume

Surrounded byECal and muondetector3D

ST

•  DUNE PRISM

beamMove detector normal to the beam to sample

different spectra for reproducing the observedspectrum at the far site by linear combination

Procedures For Moving Forward

•  In the November ND workshop, the Concept Design agreed on sets of questions and physics processes that the working groups should answer in this collaboration meeting and in the March ND workshop.

•  Answers to the questions and other findings from each working group will be documented as well.

•  Based on the findings of the working groups, the Concept Design then make decisions.

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Action Items At This Meeting •  Analysing magnet–  Prior to this meeting, circulate a draft document describing the

relative merits of the KLOE solenoid and a new dipole magnet–  In this collaboration meeting, the ND Concept Study should

approve the document and (if possible) make a recommendation to the EC on the choice of the magnet based on scientific merit alone

•  PRISM–  the ND Concept Study is asked to make a recommendation on

whether to continue to pursue the PRISM concept, taking into account of the physics case and the cost implications for the Near Site facilities

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KLOE Magnet: Agreed Questions•  KLOE magnet needs to be simulated with STT

in DUNEGGD•  Tabulate statistics in different physics channels

as a function of fiducial mass•  Evaluate key performance figures as a function

of energy (E) and fiducial volume (FV)–  Muon momentum/angular resolution as a function of

(E,FV)–  Electron energy/angular resolution (E,FV)–  Pi0 energy resolution and efficiency in neutrino

interactions–  Muon acceptance angle/energy for LAr (and

resulting uncertainties)

•  Background rate in ECAL and FV

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KLOE + STT•  Use modules of STT with FGT design to fill KLOE fiducial

volume:

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beam

KLOE+STT: Some Findings•  Worked out event rates with a 4.2-t fiducial mass•  Obtained momentum/energy and angular resolutions of

muons and electrons as a function of the fiducial volume

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Muons

KLOE + STT•  Physics issues–  Event rate is lower than that of FGT (smaller magnetic volume

than documented in CDR)•  νμ-e- elastic scattering: ~600/1.5 x 1021 PoT (c.f. FGT: ~1000/1.5 x 1021

PoT )–  Gamma-ray conversion is less than that of FGT–  Acceptance for reconstructing muons from LAr is smaller ?

•  More physical constraints on putting other kinds of detectors in the magnetic volume–  Could impact the capability of the ND ?

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HPgAr TPC: Agreed Questions•  What is the tracking efficiency as a function of track angle,

especially when the track is along the wire in the case of the STT?

•  What is the energy threshold for detecting protons/pions and how important is this to reduce systematics?

•  Momentum/angular resolution of all particles;•  Pi0 energy resolution and efficiency in neutrino interactions

(overlays, multiple interactions & background from rock);•  What are the uncertainties in energy scale for e/mu?•  What are the uncertainties in angular resolution?•  What are the key performance parameters for the ECAL to

detect NC pi0?•  Can neutrons be detected in the tracker?•  What is the expected performance for key channels including

yields?

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ArgonCube

HPgTPCinDipole

Same amount of magnetic volumeas FGT

TPC:5.2 m diameter5 m long

HPgArTPC in Dipole Magnet12

•  Event rate–  1-t fiducial mass in magnetic field–  νμ-e- elastic scattering: 135/1.5 x 1021 PoT (in KLOE magnet, reduced by ~61%)–  Gamma-ray conversion is a lot lower than that of FGT

HPgArTPC: Performance13

B = 0.4T

Momentum and angular resolutions are similar to those of KLOE+STT

Energy resolutionof ECAL (being optimized)

STT in Dipole Magnet14

Findings and Plan on Magnet•  A lot of progress has been made since the ND November

workshop–  Studies using common software tools have begun–  Some agreed questions have been addressed–  HPgAr TPC team has draft a document summarizing their work

•  https://indico.fnal.gov/event/16205/

•  There are still outstanding questions that should be addressed before a recommendation on the magnet can be made–  Plan:

•  Complete the remaining studies and report findings in the ND weekly meeting in the next two weeks

•  KLOE team will document their studies in a written document•  Concept Design co-ordinators will draft a report summarizing the relative

merits of the two magnet options based on documented findings in the third week of February

•  Concept Design approves the report by the first week of March

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LAr TPC: Questions•  The following questions/issues need to be addressed–  Can the LAr detector handle high rates?–  The feasibility of the pixel readout needs to be demonstrated.

•  The answers to the following questions might influence the detailed design–  What is the optimal height of the active volume based on scientific

needs?–  Can neutrino-electron elastic scattering be measured?–  What size is needed for hadron containment?–  Is a side muon spectrometer needed?–  What is the statistics in the fiducial volume?–  What is the muon acceptance for neutrino interactions in LAr for

different tracker options?–  What are muon/electron momentum resolution and scale error?–  Can the LAr detector measure neutrons?

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LArPix: LAr TPC Pixelated Readout•  Bench test of 1st version of 32-channel chips:

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Design Measured

Gain 1mV/250e- ~1mV/250e-

Noise <~1600ENC ~250ENC(LN)

Power 24μW/chan(Analog) 24μW/chan

•  128-pad sensor in 10-cm LAr TPC:

LArTPC: Pile-up Study•  Use π0’s in the study–  How energy resolution is

degraded if charge is missed/misidentified in reconstruction

–  At 2 MW•  ≈2% error in energy reconstruction•  < 1% for > 70% of events

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Encouragingpreliminary result

DUNE PRISM•  Questions to be addressed–  How well can PRISM address the beam-related systematic issues

in the oscillation analysis?–  How can it help to decouple the beam-related systematic

uncertainties from those coming from cross section and energy scale?

–  How does it improve CP sensitivity? A full study to address this would be the best, but maybe a few case studies are adequate.

•  The PRISM working group is making good progress in answering the questions–  A copy of the draft document is available at

https://indico.fnal.gov/event/16205/

•  ND Concept Study recommends the PRISM working group to continue with their study

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3DST: Detector Configuration20

3DST: Questions•  What are the angular/energy resolutions of the 3DST for

photons, muons and electrons? •  How well can it do neutrino-electron elastic scattering? •  How big does the 3DST target have to be to do reasonably

well with Pi0 topologies and neutrons?•  Can it do something with neutron counting/angles?•  Does it have to be in the magnetic field? •  What is the complementary physics relative to the other

trackers that can be addressed with the 3DST?

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3DST: Some Results22

•  1 x 1 x 1 cm3 scintillator cubes•  3DST: 2.4 (w) x 2.4 (h) x 2.0 (l) m3

•  With 25 cm FV cut from the edges- Fiducial mass = ~5.5 t - νμ-e- elastic scattering: ~1100/1.5 x 1021 PoT

•  3DST must be in a magnet

Summary•  Good progress is made in understanding the performance of

various detector(+magnet) options•  The ND Concept Design–  Recommends to continue the pursue of the DUNE PRISM concept –  Delays the recommendation on the choice of magnet to the first

week of March after additional findings are available in the next two weeks

•  The fourth ND workshop will take place at Fermilab on 22-24 March–  Make recommendations on

•  Detector technology for the low-mass tracker•  DUNE PRISM•  3DST

–  Indico page of the workshop: https://indico.fnal.gov/event/15649/

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