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# System prepended metadata

title: 'LDRD 2022: Light Collection System for Modular, Pixelated LArTPCs'

---

LDRD 2022: Light Collection System for Modular, Pixelated LArTPCs
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### Planning: 2022.8.23-24

Three general configurations after reading a bit the literature:
1. Conventional NUV-sensitive SiPMs coated with wavelength shifters (WLS), and Vituiti with WLS as the reflective foils (original plan written in the proposal)
2. VUV-sensitive SiPMs, and VUV reflective foils
    - Need to check the PDE of the state-of-art VUV-sensitive SiPMs
    - Need to look for VUV reflective foils (currently only knew that teflon is well reflective to 180nm)
    - Currently as a lower priority (keep as a background process, see how much we could progress)
3. Digital SiPMs
    - Need the CMOS/readout chips designed or optimized for a specific application.  I would keep an eye on the community (in particular Fabrice) and would not include it in this project.

Conclusion: We will focus on 1., the original plan.

As the WLS is not inevitable, check the [review paper from Andrjez](https://www.mdpi.com/2410-390X/5/1/4) and Christina's work for MicroBooNE.
- My takeaway from Andrjez's paper: TPB has the best efficiency.

Next, we need to coat the Vituiti foils and SiPMs with TPB, and characterize TPB.
- Do we characterize TPB at SLAC or using others' facility?
- It seems the properties might be different on an optical bench and in LAr
- Need to characterize it in LAr detectors?
    - With radiological sources, e.g. Rn.

Related characterizations that can be done on the way:
- Measure the charge and light yield, and their anti-correlation
    - Use the 5x5x5cm<sup>3</sup> setup
    - Different HV
    - Light system developed in this LDRD
    - Preliminary charge readout system + CRYO for charge collection

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### Planning: 2022.8.26

- Look into the DUNE and DarkSide groups what kind of the arrays can be mechanically sustained in LAr temperature.
- Start with 1 readout channel for the 5x5cm<sup>2</sup> plane.  Will be interested in multiple channels when the plane gets larger.
