The Search for Improved Wavelength Shifting Plate Performance - - PowerPoint PPT Presentation

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The Search for Improved Wavelength Shifting Plate Performance - - PowerPoint PPT Presentation

Aug 15, 2022 261 likes •421 views

The Search for Improved Wavelength Shifting Plate Performance Stuart Mufson, Brice Adams, Brian Baugh DUNE Photon Detector Workshop May 17, 2016 Motivation: The properties of the photon detectors are separable and can be studied/optimized

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SLIDE 1

The Search for Improved Wavelength Shifting Plate Performance

Stuart Mufson, Brice Adams, Brian Baugh DUNE Photon Detector Workshop May 17, 2016

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SLIDE 2

Motivation: The properties of the photon detectors are separable and can be studied/optimized independently. These PD properties include –

  • 1. attenuation length
  • a. Eljen light guides are a commercial product

with uniformly excellent attenuation length (> 2m)

  • b. issue resolved for IU technology
  • 2. brightness
  • a. relative brightness
  • optimization of wavelength shifting plates
  • b. absolute brightness/efficiency
  • 3. SiPM aging
  • a. reasonable performance in IU tests
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SLIDE 3

Testing Plan:

  • 1. Establish technology performance @ 128 nm in

VUV monochromator

  • (relatively) rapid method for testing/comparing

many technologies

  • 2. Show that technology performance in VUV monochromator

correlates with performance in liquid argon without Eljen light guide

  • setup in local dewar at IU: α source/plate technology/SiPM
  • 3. Test performance with Eljen light guides to demonstrate

PD system performance in local dewar

  • if feasible, test at Fermilab in TallBo/Blanche under

under controlled conditions

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SLIDE 4

Search Matrix

* TallBo plates IU solution: TPB, DCM MIT: TPB, toluene, acrylic, alcohol

°

substrate method of application wavelength shifting solution 1side/2side acrylic 1/16" spray/bake IU 1 side polycarbonate 1mm paint MIT polycarbonate 0.004" dip coated heat shrink (Walmart) spray heat shrink 0.001" HVLP vinyl sheet by hand vinyl 1/16" mylar 0.004" saran wrap fused silica crystal quartz

* * * *

°

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SLIDE 5

VUV Monochromator Measurements

  • McPherson model 234 VUV Monochromator with H2 lamp
  • Vacuum connection to a turbo pump, pumped down

to purge N2, O2, H2O

  • Backfilled with pure gaseous argon (slightly overpressured)
  • Calibrate H2 lamp with NIST calibrated photodiode

VUV light

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SLIDE 6

Issues:

  • MgF2 window becomes less transparent with exposure to

128 nm light

  • characterize technology performance with metric:

( waveshifted optical light as measured by SiPM)/ (128 nm light as measured by NIST photodiode)

0.0E+00 5.0E-10 1.0E-09 1.5E-09 2.0E-09 2.5E-09 3.0E-09 3.5E-09 4.0E-09 3/11/16 3/21/16 3/31/16 4/10/16 4/20/16 4/30/16 5/10/16 5/20/16

VUV (current - dark current) [A]

VUV current measured by NIST photodiode vs date: cleaned 3/21; 4/1; 4/14; 5/3

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SLIDE 7

y = 65950x-0.438

0.E+00 1.E+04 2.E+04 3.E+04 4.E+04 5.E+04 6.E+04 7.E+04 5 10 15 20 25 30 35 40 45 50

y = 0.0001x + 1.0089

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 5 10 15 20 25 30 35 40 45 50

Issues:

  • Monitor systematics by continuously measuring a standard

wavelength shifting plate: sprayed/baked acrylic plate, similar to TallBo #5 plate

  • radiation damage to standard, when corrected, shows stable

system performance (SiPM current – dark current)/ ( VUV current – dark current) corrected for radiation damage

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SLIDE 8

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 1 6 11 16 21 26 31 36 41 46 51 56 62 67 72 77 82 87 92 97 102

SiPM current/VUV current measurement

SiPM current/VUV current

Summary of all technologies tested:

  • measurement standard red
  • TallBo #5 waveshifting plates (Denver’s talk) blue
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SLIDE 9

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 1 6 11 16 21 26 31 36 41 46 51 56 62 67 72 77 82 87 92 97 102

SiPM current/VUV current measurement

SiPM current/VUV current

SiPM current/VUV current

Entries 104 Mean 1.559 RMS 1.526

1 2 3 4 5 6 7 8 10 20 30 40 50

SiPM current/VUV current

Entries 104 Mean 1.559 RMS 1.526 SiPM current/VUV current for all technologies tested

Summary of all technologies tested:

  • measurement standard red
  • TallBo #5 waveshifting plates (Denver’s talk) blue
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SLIDE 10

0.00 1.00 2.00 3.00 4.00 5.00 6.00 1 3 5 7 9 11

SiPM current/VUV current

1/16" acrylic, sprayed & baked TallBo plates solid

SiPM current/VUV current

Entries 104 Mean 1.559 RMS 1.526

1 2 3 4 5 6 7 8 10 20 30 40 50

SiPM current/VUV current

Entries 104 Mean 1.559 RMS 1.526 SiPM current/VUV current for all technologies tested

Sprayed/Baked technology used in TallBo #5:

  • sprayed with computer controlled spray apparatus,

baked at 80 C

  • good performance with room for improvement over

TallBo performance

  • VUV enables QC to select best performance
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SLIDE 11

0.0 1.0 2.0 3.0 4.0 5.0 6.0 1 3 5 7 9 11

SiPM current/VUV current

Heatshrink (Walmart), dipped, brushed, sprayed

SiPM current/VUV current

Entries 104 Mean 1.559 RMS 1.526

1 2 3 4 5 6 7 8 10 20 30 40 50

SiPM current/VUV current

Entries 104 Mean 1.559 RMS 1.526 SiPM current/VUV current for all technologies tested

Heat shrink material (Walmart) shows best consistent performance

  • currently being tested at MTS for contamination issues
  • has only been fixed to small samples of Eljen light guides
  • promising but obviously needs some work
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SLIDE 12

3 SensL SiPMs Am241 5.5 MeV α LAr dewar wavelength shifting plate

  • 2. Show that technology performance in VUV monochromator

correlates with performance in liquid argon without Eljen light guide

  • setup in local dewar at IU: α source/plate technology/SiPM

1000 2000 3000 4000 5000 6000 7000 8000 9000 1 2 3

ADC counts SiPM position

Comparison of Wavelength Shifting Plates in LAR

TallBo plate heat shrink

performance in LAr correlates with performance in VUV

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SLIDE 13
  • 3. Test performance with Eljen light guides to demonstrate

PD system performance in local dewar

  • preliminary studies encouraging, more work needed

second α source added 3 SensL SiPMs

3-day turnaround

  • 1. light guides loaded

into frame

  • 2. dewar pumped down
  • vernight; backfilled

with gaseous Ar

  • 3. LAr fill and

measurements

  • 4. warm up
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SLIDE 14

Eljen Light Guide/Wavelength Shifting Plate QC Plans Eljen light guides:

  • commercial product, if made correctly, will work
  • attenuation length measured > 2m multiple times at room

temperature and in LAr

  • test in dark box at room temperature
  • demonstrate correlation between dark box and LAr

Wavelength shifting plates:

  • demonstrated that VUV monchromator wavelength performance

at room temperature correlates with performance in LAr

  • current work at IU concerns uniformity over 3 3/8” x 12”

wavelength shifting plates as a function of technology

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SLIDE 15

Conclusions

  • demonstrated that technology performance @ 128 nm can

be studied in VUV monochromator

  • performance in VUV correlates with performance in LAr
  • two technologies have been identified as improving the

performance as see in TallBo #5

  • preliminary studies are encouraging that wavelength shifting

plates work efficiently with Eljen light guides

  • QC plans are being developed for both wavelength shifting

plates and Eljen light guides