TPB degradation study update

26.5.2026

AC group meeting

Overview TPB degradation study

Setup

• Produce 5 ACL’s with similar performance (scanner)
• 2x ACL in inert-gas/Argon atmosphere
• 1 ACL in darkness
• 1 ACL irradiated with UV
• 2x ACL in ambient atmosphere
• 1 ACL in darkness
• 1 ACL irradiated with UV
• 1x ACL in ambient atmosphere, exposed to sunlight

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Measurements

• Monitor humidity, pressure, temperature, oxygen and make a comparison between degradation
• After degradation: Check if TPB performance can be regenerated (e.g. liquid argon bath)
• Implications for packing, transporting, storing etc.

2

26.5.2026

AC group meeting

Overview setup

3

UV LED

Darkness

Darkness

UV LED

UV LED, monitoring SiPM, 3D case

T, rel.hum, O₂, P monitoring

T, rel.hum, O₂, P monitoring

Inert atmosphere (Ar, N₂?)/vacuum

ambient atmosphere

miniLFT for

cold PCB & sensors

vacuum pump

26.5.2026

AC group meeting

Setup in darkboxes

4

Intensity

Scan positions in 3D scanner

Fixed scan position in darkbox

UV LED, monitoring SiPM, 3D case

The time of scanning the ACL in the 3D scanner should be kept as little as possible, because they should stay in their respective environments. Therefore not a full ACL scan is foreseen, but only a point-like grid (see above). The fixed position with the pulsed LED and monitoring SiPM allows to measure more frequently, but with less resolution

26.5.2026

AC group meeting

Overview task list

1. EvapChamber leak & flow tests/feedthrough
2. Dark boxes & Scanner LED’s
3. Sensors (Production/calibration/Influx/Grafana)
4. Glue tests & ACL production

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5

26.5.2026

AC group meeting

Evap chamber - tasks

• Leak-checking
• Found two leaks with Helium leak checker
• Feedthrough for miniLFT
• Ongoing with Lori, meeting him this week.
• miniLFT (same as at the scanner)
• Populated by Alex - ready to be tested
• Constant flushing - Measure Argon gas-flow to keep humidity/oxygen low
• Need LAr
• Need miniLFT installed
• Need sensor v2 (Alex working on it)

6

26.5.2026

AC group meeting

Leak-checking

7

26.5.2026

AC group meeting

Leak tests - after 1 week still at ~10¹-10² mbar

8

Grafana: Dashboards -> TPB degradation study -> Evap Chamber leak tests

26.5.2026

AC group meeting

Dark boxes

• Materials ordered
• Waiting for delivery to build boxes
• Test LED-strips
• 1 UV LED strip & heat sink here, materials at Alex - test the strip (darkbox in GL?)
• Scanner LED’s
• 4 PCBs are being populated by Alex (Monitoring SiPM, UV LED’s)
• Silas is 3D printing the cases
• Need to be tested afterwards

9

26.5.2026

AC group meeting

Sensors

• Sensors production
• Setup for sensors in EvapChamber slightly different PCB, Alex working on this (Arduino inside EvapChamber)
• Sensor calibration
• Sensors (T, humidity, pressure, oxygen) show different values, need to calibrate (in arduino-code)
• Sensor Influx & Grafana implementation
• Arduino has IP adress
• Pushes to influx
• Displayed in Grafana

10

26.5.2026

AC group meeting

Glue tests & ACL production (a sticky situation…)

• Materials
• new “post-it” glue arrived, have dichroic mirror and TPB
• Test-glue that was sent from IBZ is not the exact same (seems to be a bit less strong)
• Coating chamber
• Had some issues with the contact between cooling and alu plate, fixed with some metal clamps
• New glue
• Can be removed from alu plate, dichroic mirror can be removed
• Sequence: clean alu plate -> apply glue -> apply mirror -> cut mirror to alu plate size -> wash mirror �-> put in chamber
• Issue: During washing, water was able to enter underneath the dichroic mirror�Coating really bad, when water was underneath, needs to be addressed!

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11

26.5.2026

AC group meeting

Glue tests

12

26.5.2026

AC group meeting