Electroluminescence pulse shape of ReD TPC Argel Sosa Mximo Ave - - PowerPoint PPT Presentation

University of São Paulo Physics Institute

Electroluminescence pulse shape

• f ReD TPC

Argel Sosa Máximo Ave Ivone Albuquerque Nikolas Kemmerich

"Electroluminescence pulse shape and electron diffusion in liquid argon measured in a dual-phase TPC" (Nuclear

• Inst. and Methods in Physics Research, A 904 (2018)

23–34) The idealized form of the S2 pulse shape assumes that all electrons are extracted out of the liquid at the same time: yideal(t; τ1, τ2, p, T) = p·y′

ideal(t; τ1, T)+(1−p)·y′ ideal(t; τ2, T)

where y′

ideal(t; τ, T) = 1

T        0, if t < 0 1 − e−t/τ, if 0 ≤ t ≤ T e−(t−T)/τ − e−t/τ, if t > T

τ1 and τ2 are the fast and slow component lifetimes respectively, p is the fast component fraction and T is the transit time of the electrons across the gas pocket. More realistic equation including the diffusion of the cloud

• f electrons:

y(t; τ1, τ2, p, T, σ) = yideal ∗ gauss(0, σ) = p · y′(t; τ1, T, σ) + (1 − p) · y′(t; τ2, T, σ) where y′(t; τ, T, σ) = 1 2T (y′′(t; τ, σ) − y′′(t − T; τ, σ)) y′′(t; τ, σ) = erf

• t

√ 2σ

• − e−t/τeσ2/2τ 2erfc

σ2 − tτ √ 2στ

Model developed to DS–50 TPC

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 t ( s) 0.00 0.05 0.10 0.15 0.20 0.25 0.30 amp (arb) DS-50 data DS50 S2 Model

Effect of the SiPM single photoelectron response (SPE) on the S2 pulse shape?

2 4 6 8 10 12 14 t ( s) 0.05 0.10 0.15 0.20 0.25 0.30 amp (arb) DS-50 data DS50 S2 Model SPE Model included 2 4 6 8 10 12 14 t ( s) 10

2

10

1

amp (arb) DS-50 data DS50 S2 Model SPE Model included 2 4 6 8 10 12 14 t ( s) 0.05 0.10 0.15 0.20 0.25 0.30 amp (arb) ReD data DS50 S2 Model SPE Model included 2 4 6 8 10 12 14 t ( s) 10

2

10

1

amp (arb) ReD data DS50 S2 Model SPE Model included

The analytical model is complicated by SPE. The fit event by event is computationally expensive. We fixed the parameters [τ1=11 ns, τ2=3.45 µs, p=0.08, σ=0.2] except the transit time (T):

2 4 6 8 10 12 14 t ( s) 10

2

10

1

amp (arb) ReD data SPE Model T=0.50 s SPE Model T=1.00 s SPE Model T=1.25 s SPE Model T=1.50 s SPE Model T=2.00 s

Estimator based on the rise time of the pulse to get the transit time.

s] µ t [

5 10

CDF

0.2 0.4 0.6 0.8 1

s] µ T=0.50 [ s] µ T=1.00 [ s] µ T=1.50 [ s] µ T=2.00 [

s] µ T [

0.5 1 1.5 2 2.5

s] µ Rise Time [

1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1%-20%

Rise time distribution for run 978 taken the inner and outer channels of the TPC:

Next steps:

See dependence between transit time and electroluminiscence field. See dependence between transit time and gas pocket height.

Other options?

Maybe deconvolution of SPE + DS50 Model fit

DD–Gun + MCP (run 1039)

Sa 200 400 600 800 1000 ADC 20 − 20 40 60 80 100

Ch0 - MCP (MCP_Global)

Sa 200 400 600 800 1000 ADC 8000 − 6000 − 4000 − 2000 − 2000

Ch1 - MCP (MCP_Xp)

Sa 200 400 600 800 1000 ADC 3000 − 2000 − 1000 − 1000 2000

Ch2 - MCP (MCP_Xm)

Sa 200 400 600 800 1000 ADC 5000 − 4000 − 3000 − 2000 − 1000 − 1000 2000

Ch3 - MCP (MCP_Yp)

Sa 200 400 600 800 1000 ADC 6000 − 5000 − 4000 − 3000 − 2000 − 1000 − 1000 2000

Ch4 - MCP (MCP_Ym)

Sa 200 400 600 800 1000 ADC 8 − 6 − 4 − 2 − 2 4 6 8

Ch9 - MCP (LSci9)

Charge (Sum)/Norm

0.5 1 1.5 2

Charge(X+ X- Y+ Y-)/Norm

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

1 10

2

10

X

1 − 0.5 − 0.5 1

Y

1 − 0.8 − 0.6 − 0.4 − 0.2 − 0.2 0.4 0.6 0.8 1

10 20 30 40 50 60