Detector Physics with MicroBooNE Yifan Chen University of Bern - - PowerPoint PPT Presentation

Detector Physics with MicroBooNE

Yifan Chen

University of Bern For MicroBooNE collaboration

TAUP, Toyama, 10th September 2019

Short-Baseline Neutrino Oscillation Program (SBN)

2 Yifan Chen, University of Bern Detector physics with MicroBooNE

ICARUS SBND MicroBooNE

Booster

Neutrino Beam

8 GeV proton

600 m 470 m

Fewer νμ? More νe? Fewer νμ? More νe?

110 m

νμ Few νe νμ, few νe

Aim to understand MiniBooNE e-like low energy excess

• Excellent e/γ separation
• Excellent position and energy resolution
• Fairly low detection threshold for neutrino events

Liquid Argon Time Projection Chambers (LAr TPCs)

Ar

E-field electron drift velocity

Working Principles of LAr TPCs

3 Yifan Chen, University of Bern Detector physics with MicroBooNE

• 1. Charge particles ionising LAr
• 2. Ionised electrons drift to the anode plane

along the electric field (E-field) 3D topology 2D from read-out plane 1D from time projection 3D calorimetry Charge deposition in the read-out wires Particle identification by both topology and calorimetry

JINST 12 (2017) P02017

The MicroBooNE Detector

4 Yifan Chen, University of Bern Detector physics with MicroBooNE

• A comprehensive LAr TPC with
• Three wire read-out planes:
• ne collection Y plane (wires: vertical)

two induction U, V planes (wires: ±60°)

• 32 photomultipliers(PMT) for light readout
• UV laser system for E-field calibration
• Cosmic ray tagger
• Active mass of LAr 85 t

Total mass of LAr 170 t

• 70 kV on the cathode
• 273 V/cm E-field
• 1.098 mm/μs drift speed
• Operating on the surface
• Data taking since autumn 2015
• mm-scale spatial resolution
• 4π angular coverage
• 300 MeV momentum detection

threshold for proton

JINST 12 (2017) P02017

X : 2 . 5 6 m Y : 2 . 3 2 m Z : 1 . 3 6 m A n

• d

e C a t h

• d

e

LAr Scintillation and Light Collection in MicroBooNE

5 Yifan Chen, University of Bern Detector physics with MicroBooNE

• Bright LAr scintillation light O(10k photons/ MeV)
• 128 nm UV photons release at de-excitation of LAr excimer
• LAr is transparent to its own scintillation
• 32 PMTs (8-inch) covered by TPB-coated acrylic plates
• TPB shift the wavelength of LAr scintillation to 430 nm

(in PMT sensitive region)

• PMT readout window is ~ms around neutrino beam spill

Radioactive decay

Self-trapped exciton luminescence Recombination luminescence

Illustrated by Ben Jones

Use of Light Signal in MicroBooNE

6 Yifan Chen, University of Bern Detector physics with MicroBooNE

Trigger

• Require PMT activity in time with beam trigger
• Suppress empty beam triggered events with cosmic only activity
• The trigger rate drops by a factor of 20

Flash-matching (match the TPC energy deposit to the light signal)

• Optical flash requirement:

The integration of all PMT signals exceed a background level

• Light hypothesis:

The consistency of reconstructed light signals from the PMTs and the modelled light signal corresponding to a cluster of charge deposition

arXiv:1905.09694, accepted by PRL

Physics result using flash-matching! νμ CC inclusive cross-section measurement

Cosmic Ray Tagger (CRT)

7 Yifan Chen, University of Bern Detector physics with MicroBooNE

CRT is essential

for MicroBooNE

• To gain more information about

cosmics so to use them as calibration source and for cosmic flux study

• To remove cosmic background
• To gain precise time

information (~ ns resolution) for CRT matched tracks in the TPC (cosmic- or neutrino- induced)

• To gain an unbiased sample

for trigger efficiency study

Scintillating strips Wavelength Shifting Fibers Protection Mylar Tape SIPM on the other side 1.75 m wide 16 Scintillating Strips

JINST 14, P04004 (2019) Instruments 1 (2017)

Particle Identification by Topology and Calorimetry

8 Yifan Chen, University of Bern Detector physics with MicroBooNE

MicroBooNE is an excellent imaging detector and calorimeter, which is powerful in particle identification e/γ shower separation

• The distance in between the shower

start and the neutrino vertex

• dE/dx at the beginning of the shower

Muon, proton and pion separation

• Calorimetry profile of dE/dx,

especially of their Bragg peaks electron shower

Showers Tracks

photon shower

gap dE/dx ~ 2 M.I.P

muon 4 protons

Charge dQ/dx and Energy dE/dx

9 Yifan Chen, University of Bern Detector physics with MicroBooNE

Recombination Anode Cathode Ionisation Lifetime (charge attenuation)

by electro-negative impurities

Readout dQ/dx (a) initial dQ/dx (b) after recombination dQ/dx (c) after diffusion and impurities dQ/dx (d) from readout Charge diffusion dE/dx Wion

Dynamic Induced Current and 2D Deconvolution

10 Yifan Chen, University of Bern Detector physics with MicroBooNE

• Dynamic induced current (DIC):

drifting electrons induce the current on nearby wires

• MicroBooNE is the first to simulate DIC in LArTPC
• Vital for various track orientations
• Improvement shows in data / MC agreement

2D deconvolution in signal processing time (conventional 1D) and wires

unipolar bipolar U plane

JINST 13, P07006 (2018)

Charge Uniformity

11 Yifan Chen, University of Bern Detector physics with MicroBooNE

Charge uniformity correction is needed mainly due to readout channel response (gain factor) We use anode piercing tracks

C(y, z) = (dQ/dx)global ((dQ/dx)(y, z))local

(c) (d)

arXiv:1907.11736, submitted to JINST

Electron Lifetime

12 Yifan Chen, University of Bern Detector physics with MicroBooNE

• LAr in MicroBooNE has high

purity most of the time

• For high purity period, charge

attenuation is negligible

• For low purity period, charge

attenuation follows exponential. (electrons can be removed by electro-negative impurities)

• We use anode-cathode

piercing tracks to determine electron lifetime τ

arXiv:1907.11736, submitted to JINST

(dQ/dx)anode (dQ/dx)cathode = exp(−tdrift/τ)

(b) (c)

High purity Low purity anode cathode

Charge Recombination and Energy Deposition

13 Yifan Chen, University of Bern Detector physics with MicroBooNE

arXiv:1907.11736, submitted to JINST

• Neutrino-induced proton sample
• Use modified box model
• dE/dx from ranged-based method

(b)

Modified box model Energy deposition

NIM A 523 2004) 275

E-field electron drift velocity

Ar e-

Importance of E-field in LArTPC

14 Yifan Chen, University of Bern Detector physics with MicroBooNE

Recombination Anode Cathode Ionisation Lifetime (charge attenuation) by electro-negative impurities Readout dQ/dx (a) initial dQ/dx (b) after recombination dQ/dx (c) after diffusion and impurities dQ/dx (d) from readout Charge diffusion

E-field dependent

Calorimetry Tracking

E-field dependent

UV Laser for Independent E-field Measurement

15 Yifan Chen, University of Bern Detector physics with MicroBooNE

Top View

Anode Cathode

M3 cold mirror from laser box TPC Cryostat Feedthrough

Feedthrough

• 2 UV laser sub-system
• ne upstream, one downstream
• Both are steerable and can be remotely

controlled (first time in LAr TPCs)

• UV laser (266 nm) can generate

reproducible, long, straight tracks, with no delta rays, with no Multiple Coulomb Scattering in LAr TPC

• Provide true track position independent
• f TPC readout

> 10 m

MICROBOONE-NOTE-1055-PUB

Read-out

Cathode Anode

True Reco

D(forward) D(backward)

Measurement of Spatial Displacement

16 Yifan Chen, University of Bern Detector physics with MicroBooNE

50 100 150 200 250 X [cm] 100 − 50 − 50 100 Y [cm] 1 − 1 2 3 4

[cm] @ Z = 518 cm

true

• X

reco

X

50 100 150 200 250 X [cm] 100 − 50 − 50 100 Y [cm] 15 − 10 − 5 − 5 10 15

[cm] @ Z = 518 cm

true

• Y

reco

Y

50 100 150 200 250 X [cm] 100 − 50 − 50 100 Y [cm] 1 − 0.8 − 0.6 − 0.4 − 0.2 − 0.2 0.4 0.6 0.8 1

[cm] @ Z = 518 cm

true

• Z

reco

Z

MicroBooNE Laser Data

• Track Iteration: map the reconstructed

tracks to true tracks

• Boundary Condition: no spatial

distortion at the anode

• Interpolation to form regular grid

ti ri di Lentry Lexit TPC

t ri

i

Z X or Y

MICROBOONE-NOTE-1055-PUB

∆t ∆t ∆X

Cathode

∆t

− → Rn

Anode

50 100 150 200 250 X [cm] 100 − 50 − 50 100 Y [cm] 8 − 6 − 4 − 2 − 2 4 6 8

[%] @ Z = 518 cm ) / E

• E

x

(E

50 100 150 200 250 X [cm] 100 − 50 − 50 100 Y [cm] 15 − 10 − 5 − 5 10 15

[%] @ Z = 518 cm / E

y

E

50 100 150 200 250 X [cm] 100 − 50 − 50 100 Y [cm] 2 − 1.5 − 1 − 0.5 − 0.5 1 1.5 2

MicroBooNE Laser Data

[%] @ Z = 518 cm / E

z

E

E-field (kV/cm) 0.1 0.2 0.3 0.4 0.5 0.6 s) µ Drift speed (mm/ 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8

MicroBooNE 273.9 V/cm

Measurement of Local E-field and Drift Velocity

17 Yifan Chen, University of Bern Detector physics with MicroBooNE

MICROBOONE-NOTE-1055-PUB

|− → vn| = |− → Rn| ∆x |− → v0|

|− → v0|

is the drift speed used to reconstruct laser tracks

Summary

18 Yifan Chen, University of Bern Detector physics with MicroBooNE

• MicroBooNE has been successfully taking data for 4 years
• MicroBooNE, as a comprehensive LAr TPC experiment, integrates light detection

system, CRT and UV laser calibration system for calibration and physics analysis.

• We explore detailed detector performance of LAr TPC which becomes useful for

future LAr TPCs such as DUNE and SBN detectors

• We are pioneer in such aspects of LAr TPCs:
• First simulation of DIC in readout response and 2D deconvolution in signal

processing in LAr TPC

• Establish the first consistent and inclusive calibration procedure for LAr TPCs:

✴ First data-driven spatial displacement and E-field maps ✴ Use extensive cosmic ray muons for charge uniformity, electron lifetime

and response calibration

✴ Use neutrino-induced protons for recombination calibration

Multiple Coulomb Scattering for Particle Momentum

19 Yifan Chen, University of Bern Detector physics with MicroBooNE

MicroBooNE’s take of Highland formula

• At given momentum, the multiple coulomb scattering

(MCS) angles of certain particle type follow Gaussian distribution

• Sweep momentum from 0.001 GeV to 7.5 GeV to get

the minimum negative log likelihood (-LL)

• Test MCS momentum -LL with inverse track direction
• Used in the νμ CC inclusive cross-section

measurement

JINST 12 P10010 (2017)

Response Calibration (ADC to e-)

20 Yifan Chen, University of Bern Detector physics with MicroBooNE

Bethe-Bloch Modified box model with residual and CSDA

Use cosmic-induced stopping muon to select a M.I.P region (250 - 450 MeV) Fit Ccal (ADC to e-) iteratively with modified box model

arXiv:1907.11736, submitted to JINST