Simulation and reconstruction of scintillation light with X-ARAPUCA photodetectors in SBND

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11/24/2022 Rodrigo Alvarez-Garrote

Simulation and reconstruction of scintillation light with X-ARAPUCA

photodetectors in SBND

Rodrigo Alvarez-Garrote [email protected]

XIV CPAN DAYS

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Outline

● Introduction to LArTPCs

● The Short-Baseline Near Detector

○ SBND Photo Detection System

● Light simulation and reconstruction

● Conclusions

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Liquid argon time projection chamber

●

Charged particles produce ionization electrons and scintillation photons inside the TPC.

●

Electric ﬁeld drifts e

^-

towards anode plane.

●

Wire planes(or other readouts) detect the e

^-

producing 3D mm-level resolution images.

●

Photon sensors measure the interaction time t

₀

with ns precision.

3

Transparent to its own scintillation light

High atomic number = more targets

Dedicated cryogenic infrastructure T_LAr~ 88 K High purity required

H₂O, O₂< 1ppb

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Liquid argon scintillation light

Ar⁺

𝛾₁₂₇

Ar₂*

Ar Ar*

Excitation

Ionization

e^-

Ar Ar 𝜏_singlet ~ ns

𝜏_triplet ~ 1.5 𝜇s

+

𝜇

Ar₂⁺

e^- Liquid Ar

Gas Ar

Fast component (singlet) Slow component (triplet)

Emission spectra of

argon

𝛾₁₂₇ Ar

Ar

+

EPL (2010), 91(6), 62002 Recombination

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SBND

It’s me, Rodrigo!

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The Short-Baseline Near Detector (SBND)

● 112 ton LArTPC, located in Fermilab (Illinois)

● 110 m from the Booster Neutrino Beam target, E_𝜈 ~0.8 GeV

● 10²¹ PoT, expected world highest-statistics from many 𝜈-Ar processes

● Data taking starting in end 2023 (TPC already constructed)

Rich physics program:

● Light sterile neutrino searches as a part of the SBN program (with ICARUS experiment as far detector)

● Other BSM searches (HNL, light dark matter…)

● R&D in new scintillation detection technologies:

X-ARAPUCAs, reﬂective TPB-coated foils...

Neutrino interaction (red) overlap with cosmic background (grey) Frontiers in Artificial Intelligence 4 (2021).

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2 diﬀerent technologies

● 120 8”-Hamamatsu Photomultiplier tubes (PMTs).

Reference well-known sensors.

● 192 X-ARAPUCAs: new scalable technology under development, low operation voltage (~40 V).

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SBND Photon Detection System

Visible and VUV X-ARAPUCAs Uncoated PMT

(Visible light) TPB-Coated PMTs (Vis+VUV light)

Nucl. Instrum. Meth. A, 985 (2021)

VUV Light

Visible Light

Physics Procedia, 2012 º

TPB absorption &

emission spectra -Directly produced in

LAr volume

-Rayleigh scattering length ~1 m

- Re-emitted by TPB foils in the cathode plane

- Rayleigh scattering length ~20 m

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Cathode

Simulation in LArSoft framework:

● 𝜈-nucleus interactions are simulated with GENIE

● Propagation inside the TPC with Geant 4

● Full simulation of readout response and reconstruction done in LArSoft (my work)

SBND light simulation

VUV γ

visible γ

TPB coated foils Photon Detection

System

➔ Up to 6500 PE per BNB-𝜈 interaction.

〈E〉

𝜈 ~ 0.8 GeV

Anode

X-ARAPUCA SiPMs signals from calibration data

PMT raw simulated signal

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11/24/2022

Rodrigo Alvarez-Garrote 9

SBND light reconstruction chain

Identify time and charge from processed signals (hits).

Cluster hits in time coincidence (ﬂashes) to claim an interaction happened.

➔ Over 95% of the interactions reconstructed (with an associated light ﬂash nearby):

|t₀-t_reco| <100 ns

For events with more than 50 MeV deposited energy.

Signals present overshoot due to AC couplings.

Speciﬁc workﬂow developed &

validated:

1. Truth time distribution of arriving photons

2. Sensor response and dark current, electronics noise, afterpulses…

3. Deconvolution with FFT &

Gaussian ﬁlter

MicroBooNE, JINST 13.07 (2018): P07006.

SBND Preliminary simulation

BNB-𝜈 interactions

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SBND light reconstruction results

MicroBooNE, JINST 13.07 (2018): P07006.

➔ Drift coordinate reconstructed within

±20 cm using only light information.

Signals present overshoot due to AC couplings.

Speciﬁc workﬂow developed &

validated:

1. Truth time distribution of arriving photons

2. Sensor response and dark current, electronics noise, afterpulses…

3. Deconvolution with FFT &

Gaussian ﬁlter

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11/24/2022

Reconstruction results: charge resolution

➔ Reconstructed energy is within 5% bias & 10% spread for

BNB-like interactions. Flash matching: compare TPC (e^-) and light (γ) information to

further reject our backgrounds!

MicroBooNE, JINST 15.03 (2020): C03023.

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Reconstruction results: time resolution

➔ Interactions outside expected beam buckets might hint new physics!

Beam inner structure

➔ 𝚫t<3ns allows us to resolve the beam inner structure, already achieved by PMT subsystem (plot on the right), with a faster sampling frequency.

SBND Preliminary

simulation BNB-𝜈 interactions Not correcting

propagation delay

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11/24/2022

Conclusions

● SBND will measure millions of neutrino interactions with high spatial and calorimetric resolution, and search for exciting new physics: light sterile neutrinos, HNL, lightDM … See José talk for details.

● SBND PDS includes novel photo-sensors and diﬀerent types of detected light (VUV and visible).

● The proper simulation and reconstruction of the light further boosts SBND performance and its sensitivity to new physics.

● SBND analysis and R&D are paving the way for future LArTPC experiments such as DUNE, with a PDS composed of X-ARAPUCAS.

● Stay tuned, SBND will start data taking next year!

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Backup

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Particle ID in a LArTPC

● Topology

○ Tracks: muons, protons, pions

○ Showers: electrons & photons

● Calorimetry: bragg peak, deposited energy proﬁle

15 MicroBooNE display of event data, color scale

inicates amount of deposited charges

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Estimation of tslow

reference PMT Deconvolved

SiPM signal

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PMT: photomultiplier tube

17

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Simulation and reconstruction of scintillation light with X-ARAPUCA photodetectors in SBND