Photon Detection Simulation utilizing Geant4 and GATE Kyle Spurgeon - - PowerPoint PPT Presentation

Photon Detection Simulation utilizing Geant4 and GATE

Kyle Spurgeon

Syracuse University

October 9, 2018

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Up to Now

We have been simulating the various photon detector designs for

• DUNE. All tested geometries begin with the frame model from

Dave Warner, pictured below. We began by verifying out Geant4 simulation with data for thin layers of TPB and measurements of the dougle shift light guide. We applied these to the Double-shift light guide, ARAPUCA, and X-ARAPUCA models.

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End scheme detector geometry. 12 Sensl C-series SiPMs on each end, for a total of 24. Side scheme detector geometry. 48 Sensl C-series SiPMs on each side, for a total of 96.

Effective Area of SiPM

The SensL C-series SiPMs are simulated throughout, and for use in calculations of optical gain for comparison, we find the effective area of a TPB coated SiPM. This effective area is affected by its detection efficiency, the efficiency of the TPB wavelength shifter, and associated geometrical factors. This system was simulated to have a detection efficiency of .127, leading to a SiPM effective area of ASiPM,eff = .046cm2

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Results for Double Shift Light Guide Geometry

0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.01

50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4

50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4 40 − 20 − 20 40 4 − 2 − 2 4

End Scheme ◮ Average area per SiPM =.306m2 ◮ Optical Gain (g), defined as Aeff /ASiPM,eff ,= 6.66 Side Scheme ◮ Average area per SiPM = .073cm2 ◮ g = 1.59

5/25 Aeff ,end (FullModuke) = 14.7cm2 Aeff ,side(FullModule) = 14cm2

0.0005 0.001 0.0015 0.002 0.0025 0.003

50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4 50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4

The efficiency maps for three of the detectors from the end scheme

• simulation. We can see that the detectors in the end scheme see

photons from the entirety of the bar, with a cone of maximal absorption.

6/25 Aeff = .294cm2 Aeff = .293cm2 Aeff = .290cm2

0.0005 0.001 0.0015 0.002 0.0025 0.003

50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4 50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4 50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4

The efficiency maps for four of the detectors from the side scheme

• simulation. We can see that the detectors this scheme see

substantially less of the light guide, but the cone of maximal absorption is still present.

7/25 Aeff = .054cm2 Aeff = .067cm2 Aeff = .048cm2 Aeff = .059cm2

Double Shift Light Guide Conclusions

It can be seen that, for the double-shift light guide (DSLG) geometeries, the End scheme results in an overall higher effective area than the side scheme, while only using 1/4 of the SiPMs, due to each SiPM having a larger effective area. Design Aeff (cm2) # SiPMs Aeff /SiPM(cm2) g End DSLG 14.7 48 .31 6.66 Side DSLG 14 192 .07 1.59

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ARAPUCA Designs

Two ARAPUCA designs were tested, with one being the proposed pTP based design while the other is a logical step from that design to the proposed XARAPUCA design. The first has pTP as the

• uter WLS, and TPB as the inner.

All parts of the prior simulations are well validated, so there is a lot

• f confidence in those results. For the ARAPUCA simulations,

there are some components that lack such confidence ◮ pTP is not well known: we have modeled the VUV response identically to TPB ◮ The properties of the green WLS layer we use have been adopted from EJ-280, where some of the physical properties have been adjusted to reflect those of a thin crystal layer. ◮ Acrylic was used instead of fused silica ◮ We use the same SiPM model throughout, that of the SensL C-series. ◮ The original dichroic filter data was obtained from Carlos Escobar, and was edited for implementation with the green WLS.

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TallBo 2017 validation

20 − 15 − 10 − 5 − 5 10 15 20 4 − 3 − 2 − 1 − 1 2 3 4

0.002 0.004 0.006 0.008 0.01 0.012 0.014

Detection Efficiency

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A cartoon for the geometry of this design can be seen to the right. The resulting effective area is Aeff (FullModule) = 3.44cm2 Aeff /SiPM = .215cm2 g = 4.67

TallBo 2017 Validation

Dante Totani presented results from the TallBo 2017 run. It was found that the ARAPUCAs tested (of the design on the previous page) had an average efficiency of ¯ η = .0077. The total area of the design is 9.8 × 7.8 × 4 = 305.76cm2. Multiplying this by the average efficiency gives and effective area of Aeff (FullModule) = 2.35cm2. The simulated geometry has an effective area of 3.44cm2. Data shows that the actual effective area of this geometry is 70% of this, so we have implement a TallBo Factor of .7 and applied it to the pTP layer, to account for this discrepancy between experiment and the simulation.

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pTP - TPB Design for Outer ARAPUCA

pTP Dichroic filter Reflective Surface LAr TPB Acrylic SiPM

0.005 0.01 0.015 0.02 0.025 0.03 40 − 20 − 20 40 4 − 2 − 2 4

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A cartoon for the geometry of this design can be seen to the right. The resulting effective area is Aeff (FullModule) = 33.25cm2 Aeff /SiPM = .35cm2 g = 7.53

TPB - Green WLS Design for Outer ARAPUCA

TPB Dichroic filter Reflective Surface LAr Green WLS Acrylic SiPM

0.005 0.01 0.015 0.02 0.025 0.03 40 − 20 − 20 40 4 − 2 − 2 4

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A cartoon for the geometry of this design can be seen to the right. The emission spectrum for this WLS is that of EJ-280, for simplicity. The modeled absorption lengths are those of EJ-280 scaled so that the absorption characteristics of a 2µm thin layer of pure WLS is analogous to that of TPB. The resulting effective area is: Aeff (FullModule) = 45.7cm2 Aeff /SiPM = .17cm2 g = 3.70

pTP - TPB Design for Inner ARAPUCA

pTP Dichroic filter LAr TPB Acrylic SiPM

0.005 0.01 0.015 0.02 0.025 0.03 40 − 20 − 20 40 4 − 2 − 2 4

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A cartoon for the geometry of this design can be seen to the right. The resulting effective area is Aeff (FullModule) = 27.9cm2 Aeff /SiPM = .21cm2 g = 4.50

TPB - Green WLS Design for Inner ARAPUCA

TPB Dichroic filter LAr Green WLS Acrylic SiPM

0.005 0.01 0.015 0.02 0.025 0.03 40 − 20 − 20 40 4 − 2 − 2 4

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A cartoon for the geometry of this design can be seen to the right. The resulting effective area is Aeff (FullModule) = 21cm2 Aeff /SiPM = .11cm2 g = 2.38

ARAPUCA Conclusions

Design Aeff (cm2) # SiPMs Aeff /SiPM(cm2) g End DSLG 14.7 48 .31 6.66 Side DSLG 14 192 .07 1.59 pTP Inner 27.9 192 .15 3.16 Green Inner 21 192 .11 2.38 pTP Outer 33.25 192 .17 3.7 Green Outer 32.6 192 .17 3.70 The summary table for the geometries discussed to this point, comparing the optical gain, effective areas, and number of SiPMs present. Note: the green WLS geometries could be significantly improved with a more selective choice of wavelength shifter.

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Dichroic Filter Implementation- XARAPUCA

The geometries implemented for this design is the same as the Double Shift Light Guide, but with a dichroic filter placed on the inside of the acrylic plates along the exterior. A cartoon is given. The SiPMs are located either along the sides (long edge) of the frame, or on the ends (short edge) as with the DSLG.

TPB Dichroic filter LAr Acrylic EJ-280 WLS

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Efficiency Maps

0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04

40 − 20 − 20 40 4 − 2 − 2 4

40 − 20 − 20 40 4 − 2 − 2 4 50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04

40 − 20 − 20 40 4 − 2 − 2 4

40 − 20 − 20 40 4 − 2 − 2 4 40 − 20 − 20 40 4 − 2 − 2 4

18/25 Aeff = 48.5cm2 Aeff = 49.62cm2

Detectors on Ends Detectors on Sides

Dichroic Filter Without filter- see slide 1 Dichroic Filter Without filter- see slide 1

Aeff /SiPM = 1.01, g = 21.97 Aeff /SiPM = .39, g = 6.30

0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.01

50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4 50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4

The efficiency maps for three of the detectors from the end scheme

• simulation. We can see that the detectors in the end scheme see

photons from the entirety of the bar, with a cone of maximal absorption.

19/25 Aeff = 1.005cm2 Aeff = 1.002cm2 Aeff = .971cm2

0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.01

50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4 50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4 50 − 40 − 30 − 20 − 10 − 10 20 30 40 50 4 − 2 − 2 4

The efficiency maps for four of the detectors from the side scheme

• simulation. We can see that the detectors this scheme see

substantially less of the light guide, but the cone of maximal absorption is still present.

20/25 Aeff = .221cm2 Aeff = .279cm2 Aeff = .208cm2 Aeff = .257cm2

X-ARAPUCA Conclusions

It can be seen that the introduction has an overall positive effect

• n effective area for both SiPM geometries. It is also seems that

the Dichroic filters have a short range of maximal improvement (≃ 5-10cm, per the plots). There is a gain at long distances, but it is a lower factor than short range. This results is a much greater increase in the effective area for the Side scheme as opposed to the end scheme.

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Design Aeff (cm2) # SiPMs Aeff /SiPM(cm2) g End DSLG 14.7 48 .31 6.66 Side DSLG 14 192 .07 1.59 pTP Inner 27.9 192 .15 3.16 Green Inner 21 192 .11 2.38 pTP Outer 33.25 192 .17 3.7 Green Outer 32.6 192 .17 3.70 X-ARAPUCA End 48.5 48 1.01 21.97 X-ARAPUCA Side 49.62 192 .29 6.30

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Backup - Dichroic Filter Graphs

300 350 400 450 500 550 600 Wavelength (nm) 0.2 0.4 0.6 0.8 1

Transission Reflection ptp emission TPB emission (Max normalized)

Test of Dichroic Filter

300 350 400 450 500 550 600 Wavelength (nm) 0.2 0.4 0.6 0.8 1

Transission Reflection EJ-280 emission TPB emission (Max normalized)

Test of Dichroic Filter - TPB Shifted

24/25 Integral of the tpb emission =57.2 Integral of TPB emission ∗ Transmission% = 39.1 A decrease in transmission of 32%

Backup - Outer Arapuca Geometry w/o Dichroic filter

0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.01 40 − 20 − 20 40 4 − 2 − 2 4 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.01 40 − 20 − 20 40 4 − 2 − 2 4

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Green Aeff = 8.32cm2- g = 1.88 pTP: Aeff = 6.35cm2- g = 1.43 So, the reflective ARAPUCA designs see an increase of 2 and 5.25 for the green WLS and pTP, respectively, which bounds the increase of 3-4 times seen in the DSLG.