Status of the light signal simulation for ProtoDUNE-DP Anne - - PowerPoint PPT Presentation

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Status of the light signal simulation for ProtoDUNE-DP Anne - - PowerPoint PPT Presentation

Nov 06, 2022 415 likes •661 views

Status of the light signal simulation for ProtoDUNE-DP Anne CHAPPUIS Isabelle DE BONIS Dual-Phase Photon Detection System Consortium Meeting September 21th 2017 1/23 Introduction 6x6x6m 3 (fjducial) DLAr TPC @CERN The light signal

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SLIDE 1

1/23

Status of the light signal simulation for ProtoDUNE-DP

Anne CHAPPUIS – Isabelle DE BONIS

Dual-Phase Photon Detection System Consortium Meeting September 21th 2017

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SLIDE 2

2/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

 The light signal simulation can be divided in

2 distinct parts:

Scintillation (production of the photons)

Light propagation in the detector

 This talk focuses on the light propagation

simulation:

Using pre-calculated maps

For 6x6x6m3 and 3x1x1m3 detectors Simulations performed using the LightSim software based on GEANT4

Introduction

36 PMT s

 Outline:  Light signal in ProtoDUNE-DP  Light map production procedure  Light map characteristics  Examples of map utilization

6x6x6m3 (fjducial) DLAr TPC @CERN 3x1x1m3 (fjducial) DLAr TPC @CERN 5 PMT s

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SLIDE 3

3/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Light Signal in ProtoDUNE-DP

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SLIDE 4

4/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Light production in Liquid Argon

Scintillation (S1) photon characteristics:

λ = 128nm (E = 9.69eV)

Isotropic emission

2 contributions with difgerent lifetimes:

τF

ast = 6ns

τSlow = 1600ns LAr GAr

e- S1

Direct excitation scintillation photon (S1 Signal) Ionisation e- / ion pair creation electron drifted toward the anode

recombination

Charge particle crossing LAr

Time [ns] 50 100 150 200 250 300 350 400 450 500 S1 Signal [ph/5ns] 10 20 30 40 50 60

S1 signal induced by a 10-GeV muon Fast contribution to S1 Slow contribution to S1

ProtoDUNE-DP

Simulation based on the NEST approach (arXiv:1106.1613v1) Not detailed here

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SLIDE 5

5/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

For the time being, G is estimated ~300ph/e → Has to be determined more precisely

Light production in Argon Gas

Not recombined electrons are drifted toward the top of the detector.

Dual-Phase technology : e- travel through Ar gas. → Production of S2 photons:

S2 photon production by electroluminescence:

Simulation: the 3 productions are taken into account via an electroluminescence gain G LEMs

(e- amplifj fjcation)

Extraction Grid

e-

Anode

3 1 2

λ = 128nm (E = 9.69eV)

Lifetimes:

τF

ast = 7ns

τSlow = 3200ns

G = Number of photons produced in GAr / drifted electron

From the LEMs during e- amplifj fjcation:

Main contribution

Need additional work and simulations to be precisely determined

Between LAr surface and LEMs

Between LEMs and anode 1 2 3

Need to estimate the number of photons emitted toward the PMT array LAr GAr

e- S1 S2

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SLIDE 6

6/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Light propagation simulation : light maps

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SLIDE 7

7/23 Anne CHAPPUIS, 18 May 2017 ProtoDUNE-DP

Implementation of the detailed geometry

Light collection: 36 TPB-coated PMT s

2 options for the PMT positioning:

Non-uniformly spaced (to cover the full fjducial area)

Uniformly spaced (more dense confjguration)

LEM Plates Extraction grid Field cage Ground grid Cathode pipes + supporting structure

Z X Y Implementation of all the components that have an impact on the photon trajectories

Visualization from LightSim

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SLIDE 8

8/23 Anne CHAPPUIS, 18 May 2017 ProtoDUNE-DP

Light Propagation in ProtoDUNE-DP

Propagation of scintillation photons (128nm):

Absorption in LAr

Rayleigh scattering on LAr molecules

Absorption on difgerent detector components (fjeld cage, cathode supporting structure, tank…)

Problematic:

Very large amount of photons (ex: for a 5-GeV muon track, production of 65.106 scintillation photons)

T racking each scintillation photon takes a lot of time

Less than 1% of photons fjnally reach the PMT s

The exact knowledge of all the photon tracks is not needed

Solution: simulate the tracks only once, and store the useful information in Light Maps

Note: these maps describe the photon propagation → Independent from the scintillation parameters

λRayleigh =200m λRayleigh = 55cm

(arXiv:1502.04213v2)

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SLIDE 9

9/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Light map production procedure

Solution: simulate the tracks only once, and store the useful information in Light Maps

For each photon production point in the detector, and each PMT, the map gives:

Probability to reach the PMT

T ravel time distribution

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SLIDE 10

10/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Light map production procedure

Solution: simulate the tracks only once, and store the useful information in Light Maps

For each photon production point in the detector, and each PMT, the map gives:

Probability to reach the PMT

T ravel time distribution LAr and GAr volumes are split in voxels

voxel

Production point

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SLIDE 11

11/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Light map production procedure

Solution: simulate the tracks only once, and store the useful information in Light Maps

For each photon production point in the detector, and each PMT, the map gives:

Probability to reach the PMT

T ravel time distribution

voxel

LAr and GAr volumes are split in voxels Generation of N photons in each voxel Photons are tracked across the detector Production point T racking

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SLIDE 12

12/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Light map production procedure

Solution: simulate the tracks only once, and store the useful information in Light Maps

For each photon production point in the detector, and each PMT, the map gives:

Probability to reach the PMT

T ravel time distribution

voxel

LAr and GAr volumes are split in voxels Generation of N photons in each voxel Photons are tracked across the detector T ravel time distribution

  • btained for each PMT

Production point T racking T ravel time distribution

Entries 1566 Mean 40.98 Travel time [ns] 50 100 150 200 250 300 350 400 Photons reaching PMT21 20 40 60 80 100 120 140 160 180 200 220 240 Entries 1566 Mean 40.98

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SLIDE 13

13/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Light map production procedure

Solution: simulate the tracks only once, and store the useful information in Light Maps

For each photon production point in the detector, and each PMT, the map gives:

Probability to reach the PMT

T ravel time distribution

voxel

LAr and GAr volumes are split in voxels Generation of N photons in each voxel Photons are tracked across the detector T ravel time distribution

  • btained for each PMT

Extraction of time distribution parameters

Light Maps

Production point T racking T ravel time distribution

Entries 1566 Mean 40.98 Travel time [ns] 50 100 150 200 250 300 350 400 Photons reaching PMT21 20 40 60 80 100 120 140 160 180 200 220 240 Entries 1566 Mean 40.98

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SLIDE 14

14/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Light map characteristics

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SLIDE 15

15/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

 LAr maps:

Large voxels defjnition: 250mmx250mmx250mm

Number of generated photons per voxel: 107 over 4π

 GAr maps:

Voxel defjnition: 250mmx250mmx5mm

Only 1 voxel in Z

Number of generated photons per voxel: 5.108 over 4π ✔ T

  • save time, photons are generated in ~1/8 of the detector, then we use the X-Y symmetry of the

detector to reconstruct the whole map. → Gain of a factor 8 in the execution time.

 Propagation parameters in LAr

LAr absorption process is not included in the map generation → Will be parametrized when using the maps

ProtoDUNE-DP light map characteristics

Z X Y X

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SLIDE 16

16/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

T ravel time distribution characteristics

Probability to reach the PMT :

T ravel time distribution shape: strongly depends on the distance to the PMT weight = w0 = Number of photons reaching the PMT Number of generated photons

Travel time [ns] 50 100 150 200 250 300 Photons hitting the PMT 1 10

2

10 PMT14 PMT17

Photons produced 1m above the cathode pipes

Travel time [ns] 50 100 150 200 250 300 Photons hitting PMT14 1 10

2

10 Photons produced: ~1m above the cathode pipes ~2.5m above the cathode pipes

Z → Find a general parametrisation with the minimum number of parameters

ProtoDUNE-DP ProtoDUNE-DP 12 28 7 17 23 11 16 22 27 10 15 21 26 6 14 20 9 25 31 30 8 18 24 32 5 13 19 29 4 3 2 1 36 35 34 33

production point

PMT Grid

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SLIDE 17

17/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

T ravel time distribution characteristics

→ Satisfactory in most cases → Finally, 4 parameters are stored in the maps (ROOT TH3 objects)

Travel time [ns] 50 100 150 200 250 Photons hitting PMT14 20 40 60 80 100

LightSim simulation Reconstructed with Laundau fit

b)

Reconstruction for photons generated at (-1125, -1375, -2080)mm χ2=1.08

ProtoDUNE-DP

The time distribution is reconstructed using a landau fj fjt and 3 parameters:

t0 (the fjrst bin Nentries > 0)

The MPV and σ of the landau fj fjt

Voxels with Nentries<50 are not taken into account

Mean 0.9387 RMS 0.9731 /DoF

2

χ 1 2 3 4 5 6 7 8 9 10 200 400 600 800 1000 1200 Mean 0.9387 RMS 0.9731

χ2 distribution

6.2% of voxels with χ2 > 2.5:

voxels close to the PMT

ProtoDUNE-DP

Peak at χ2<0.4: voxels with a small number of collected photons

LAr light maps (ProtoDUNE-DP)

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SLIDE 18

18/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Light maps for the (3x1x1)m3 prototype

Same work as been done for the (3x1x1)m3 prototype

 108 photons generated in each voxel

(~5h per voxel)

 Same voxel defjnition: (25x25x25)cm3  Implementation of the detailed geometry

3 TPB-coated PMT s

2 PMT with TPB-coated plate above them

 Same LAr propagation parameters  Adaptation to a smaller volume:  Narrow travel time distributions  Use of a difgerent travel time parametrization:  Double-exponential parametrization  5 parameters: w0, tstart, τ1, τ2 and relative

normalization (between the two exponential)

Entries 11373

Travel time [ns] 10 20 30 40 50 60 Photons reaching the PMT 500 1000 1500 2000 2500

Entries 11373

Example of travel time distribution (3x1x1)

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SLIDE 19

19/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Scintillation light signal from light maps

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SLIDE 20

20/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Light signal using light maps

LAr GAr

e- S1 S2

Generation of cosmic muons or beam particles. At each step: simulation of the scintillation process → Number of scintillation photons and drifted electrons T racking of the particles across the detector Number of detected S1 photons:

w0 from the maps

LAr absorption length

(PMT quantum effj ffjciency) Number of detected S2 photons:

w0 from the maps

LAr absorption length

Electroluminescence gain

(PMT quantum effj ffjciency) Hit time of each photon = vertex time +scintillation time (+ drifted time) + travel time Parameters from the maps Lifetimes τF

ast and τSlow

exp(−ttravel⋅ c λAbs⋅nLAr ) λAbs = Absorption length nLAr = Refractive index Parametrization of the LAr absorption: if S2 photons

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SLIDE 21

21/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Map values interpolation

Interpolation between the 8 nearest voxels using the weighted average method (ROOT interpolation)

Interpolation of the map values to the true coordinates of the photon production point → The interpolation is satisfactory → The voxelisation is suitable MPV map for PMT11 at z=-1080mm Interpolated map (6x6x6)m3 (6x6x6)m3

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SLIDE 22

22/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

Studies using light maps

Time [ns] 4000 − 3000 − 2000 − 1000 − 1000 2000 3000 4000

3

10 × Light signal [ph/400ns] 200 400 600 800 1000 1200 1400 Light signal LAr contribution (prompt signal)

Study of the PMT positioning impact on light signal Study and rejection of the cosmic muon background These simulations and the map generation allow difgerent studies for the collaboration:

Impact of difgerent designs on the light collection

T ag and rejection of the cosmic muon background

X-coordinate [mm] 3000 − 2500 − 2000 − 1500 − 1000 − 500 − Number of photons reaching the PMT array

4

10

PMTs Uniformly spaced (65cm) PMTs Non-uniformly spaced

For 107 photons generated 1m above the cathode pipes

→ Ongoing studies

λAbs = 30m

(arXiv:1306.4605V2)

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SLIDE 23

23/23 Anne CHAPPUIS, September 21th 2017 ProtoDUNE-DP

The light propagation is simulated using pre-calculated “light maps”

Maps have been produced for (6x6x6)m3 and (3x1x1)m3 detectors

Maps for LAr (S1) and GAr (S2) light signal

Containing the detailed geometry of the detector

For the ProtoDUNE-DP map: 2 options for the PMT positioning

2 difgerent travel time distribution parametrizations (Landau and double-exponential)

→ The detector scale have a non-negligible impact on the travel time distribution shapes

Given the map format (TH3 objects), the maps can be used independently from the library that produce them

Maps implemented in QScan, and the implementation in LArSoft is ongoing (CIEMAT people)

Maps are currently used to perform light signal studies (cosmic background, impact of LAr propagation parameters…)

Foreseen: comparison with (3x1x1)m3 data

Difgerence between coated-PMT and coated-plate above PMT s

S2 estimation (w .r .t to extraction and LEM amplifjcation fjelds)

...

Summary