Analysis of the ISIS Target Station 2 Proton Beam ... - CERN
ProtoDUNE-SP Proton Analysis - CERN
Transcript of ProtoDUNE-SP Proton Analysis - CERN
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ProtoDUNE-SP Proton Analysis
Heng-Ye LiaoOn behalf of the DUNE CollaborationDPF 2019 NortheasternJuly 29, 2019
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Introduction• Protons are one of the final state particles in the neutrino charge current quasi-elastic
(CCQE) interaction. → Important for reconstructing the neutrino total energy in the interactions→ Must require precise cross section measurements
• Liquid argon TPC (LArTPC) has high resolution tracking and calorimetry. → Allow us to study neutrino-nucleus interactions in great detail
• ProtoDUNE-SP experiment→ Understand the detector responses of different particles interacting in a LArTPC→ Prototype detector that form the building blocks for DUNE
CCQEProtoDUNE-SP LArTPC
6 m
7 m
3.6 m
3.6 m
e- or μ-
n p
W
Particlebeam
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*Pandora reconstruction algorithms: “The Pandora multi-algorithm approach to automated pattern recognition of cosmic-ray muon and neutrino events in the MicroBooNE detector”, Eur.Phys.J. C78 (2018) no.1, 82
• Detector response of protons in a LArTPC- Selection of beam protons, event reconstruction & energy calibration
• Sample for analysis: 1 GeV/c proton data, 6.6K tracks • Proton event selection
- Beam proton selection: Use the info from TOF & Cherenkov counters- After entering TPC: Track reconstruction using Pandora* recognition algorithms
Pandora Event Display (Data)
Proton Event Selection Blue: Cosmic Ray ParticlesPurple: Beam ParticleRed: Trigger
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Proton Classification (Data)
Stopping Protons
0.69 1.05
Cut to select stopping protons
“Interacting” Protons
● Classification of 1 GeV/c proton events-Convert beam proton momentum to its CSDA range-Use the ratio cut (track length/CSDA range) to select stopping/interacting protons
• Stopping protons: used for calorimetry study/Particle ID• Interacting protons: for proton-Ar cross-section study
Stopping Proton
Interacting Proton
Peak position ≠ 11. Energy loss2. Space charge effect (SCE)
Wire Number
Tim
e t
icks
Wire Number
Tim
e t
icks
Collection View
Collection View
Track length:79.3 cm
Track length:36.7 cm
Beam Direction
ProtoDUNE-SP Preliminary
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X-position [cm]
Start/end points of cathode-crossing muon tracksStart/end points of cathode-crossing muon tracks
• Space charge effect (SCE): A build up of slow moving ions distributed over a region of TPC which distorts the E-field
• Ionization drift path being affected by SCE• Impact on reconstructed proton tracks
- Position / Calorimetry information (dQ/dx)
APA
Y-p
ositi
on [c
m]
*Integrate all the z-positions, ~240K tracks
ProtoDUNE-SP Preliminary
CPA
Spatial distorations > 30 cm !
Space Charge Effect
CPA APAX
Y
Z
APABottom
Top
Dow
nstr
eam
Ups
trea
m
Beam
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SCE Map
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• Use through-going anode-/cathode-piercing muons to measure spatial offsets(Muons should cause straight tracks Curvature due to space charge effect)⇒
• Measure spatial distortion at TPC faces• Spatial distortion map
- Scale simulated 3D spatial distortion map with data/MC scale factors (SF) at TPC faces- Linearly interpolate SFs across TPC bulk- Spatial distortion drift velocity E-field map⇒ ⇒
True track
Measured track
3D maps in TPC bulk
(Curvature of track due to SCE)
2D maps at TPC Faces
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SCE Correction
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• Calorimetry information (dQ/dx or dE/dx) is affected by both spatial andE-field distortions
• Apply corrections of both spatial & E-field distortions derived from data-driven calibration
- - True Track– Measured Track
Spatial CorrectionSpatial Correction Calorimetry CorrectionCalorimetry Correction
(Curvature of track due to SCE)
Impacted by SCE viaspatial distortions
Impacted by SCE viaE-field distortions
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Calibration – dQ/dx Correction
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● Calibration scheme based on the over-all correction• dQ/dx Correction (non-uniform dQ/dx ⇒ uniform dQ/dx)
- Apply SCE correction - Use TPC crossing muon tracks for the correction - Correct non-uniform dQ/dx distribution caused by SCE and attenuation
Median dQ/dx before correction (Beam Side)
Low dQ/dx due to the grounded electron diverters
*Voxel size: 5 cm x 5 cm
Side View of ProtoDUNE-SP Detector
ProtoDUNE-SP Preliminary
APA3 APA2 APA1
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Calibration
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• Select stopping muons for calibration • dQ/dx [ADC/cm] dE/dx [MeV/cm]⇒
- Tune calorimetry constant hence calibrated dE/dx matches expectation (modified box model*)
• Good agreement between data and MC for the most probable values
MIP region for calibration
Data: Stopping Muons
MC: Stopping Muons
*Reference: “A study of electron recombination using highly ionizing particles in the ArgoNeuT Liquid Argon TPC” (https://arxiv.org/abs/1306.1712)
Expectation
ProtoDUNE-SP Preliminary
ProtoDUNE-SP Preliminary
Expectation
– Data– MC
ProtoDUNE-SP Preliminary
MIP region for calibration
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Proton dE/dx vs Residual Range
ProtoDUNE-SP Preliminary
Expectation
Data
Before SCE Correction After SCE Correction
*Statistics: Data before SCE corr.:1835 /after SCE corr. (small data sample): 721 MC (before SCE corr.): 1221 / after SCE corr. (small data sample): 52
ProtoDUNE-SP Preliminary
MC
Before SCE Correction After SCE Correction
ProtoDUNE-SP Preliminary ProtoDUNE-SP Preliminary
Expectation
Expectation
Expectation
• Good agreement between data (MC) and expectation after SCE correction!
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Overall dE/dx Distributions
• Good agreement between data and MC• Improvement on dE/dx distribution after SCE correction
ProtoDUNE-SP Preliminary ProtoDUNE-SP Preliminary
Before SCE Correction After SCE Correction
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Particle Identification (Data)
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ProtoDUNE-SP Preliminary ProtoDUNE-SP Preliminary
proton
Muon
• Particle identification using a calorimetry based particle ID
• Excellent p/μ separation of ProtoDUNE-SP data!
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Summary
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• Beamline instrumentations provide accurate information on both the beam particle species and the momenta
• Proton track reconstruction using Pandora is working nicely• Calibration scheme based on the overall correction has
been developed→ Promising result after space charge correction and calibration
• Encouraging consistency between data and MC for the dE/dx distributions
• Clear separation between muon and proton of ProtoDUN-SP data• Measure of inclusive proton-Ar cross section in development
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Modified Box Model
Wion
: 23.6 [eV/ion]
c:calibration const. [ADC/ion] (c~6.155x10-3 for data being used)
ε: 0.5 [kV/cm] ρ: 1.38 [g/cm3]
β: 0.212 [(keV/cm)(g/cm2)/MeV]
α: 0.93
Reference: “A study of electron recombination using highly ionizing particles in the ArgoNeuT Liquid Argon TPC” (https://arxiv.org/abs/1306.1712)
Parameters:
dE
dx = ExpW
ionβ
dQdx
c ρ ε- α
ρ
βε