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arxiv: 2606.26284 · v1 · pith:VB5JO2XSnew · submitted 2026-06-24 · ⚛️ physics.ins-det · hep-ex

Production and installation of wavelength-shifting reflective light enhancers for the Short-Baseline Near Detector

R. Acciarri , L. Aliaga-Soplin , R. Alvarez-Garrote , D. Andrade Aldana , C. Andreopoulos , A. Antonakis , S. Balasubramanian , A. Barnard
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V. Basque J. Bateman M. C. Bazetto A. Beever E. Belchior M. Betancourt A. Bhat M. Bishai A. Blake B. Bogart D. Brailsford A. Brandt S. Brickner M. B. Brunetti L. Camilleri D. Caratelli D. Carber B. Carlson M. F. Carneiro W. Castiglioni R. Castillo Fernandez F. Cavanna A. Chappell H. Chen S. Chung R. Coackley S. Cotton J. I. Crespo-Anad\'on C. Cuesta Y. Dabburi O. Dalager M. Dall'Olio R. Darby I. de Icaza M. Del Tutto Z. Djurcic S. Dominguez-Vidales M. Dubnowski K. Duffy S. Dytman A. Ereditato J. J. Evans A. Ezeribe C. Fan A. Filkins B. Fleming W. Foreman D. Franco H. Frandini G. Fricano I. Furic A. Furmanski S. Gao D. Garcia-Gamez S. Gardiner I. Gil-Botella S. Gollapinni O. Goodwin P. Green W. C. Griffith L. Hagaman P. Hamilton B. Harris C. Harrison A. Hergenhan M. Hernandez-Morquecho P. Holanda C. James R. S. Jones M. Jung T. Junk D. Kalra G. Karagiorgi L. Kashur K. J. Kelly W. Ketchum M. King J. Klein L. Kotsiopoulou S. Kr Das T. Kroupov\'a V. A. Kudryavtsev N. Lane H. Lay R. LaZur J.-Y. Li K. Lin B. R. Littlejohn L. Liu W. C. Louis X. Lu X. Luo A. Machado P. Machado C. Mariani F. Marinho J. Marshall C. Martin-Morales A. Mastbaum K. Mavrokoridis N. McConkey B. McCusker J. Mclaughlin K. Mistry M. Mooney A. F. Moor G. Moreno Granados C. A. Moura J. Mueller S. Mulleriababu A. Navrer-Agasson M. Nebot-Guinot V. C. L. Nguyen F. J. Nicolas-Arnaldos J. Nowak S. B. Oh N. Oza O. Palamara N. Pallat V. Pandey A. Papadopoulou H. B. Parkinson J. Paton L. Paulucci Z. Pavlovic D. Payne L. Pelegrina-Guti\'errez O. L. G. Peres V. L. Pimentel J. Plows G. Putnam X. Qian R. Rajagopalan P. Ratoff H. Ray M. Reggiani-Guzzo M. Roda J. Romeo-Araujo M. Ross-Lonergan N. Rowe P. Roy A. Sanchez-Castillo P. Sanchez-Lucas D. W. Schmitz A. Schneider A. Schukraft H. Scott E. Segreto M. Shaevitz P. Singh B. Slater J. Smith R. Soares M. Soares-Nunes M. Soderberg S. S\"oldner-Rembold F. Spagliardi J. Spitz M. Stancari T. Strauss A. M. Szelc C. Thorpe D. Totani M. Toups C. Touramanis L. Tung G. A. Valdiviesso R. G. Van de Water A. V\'azquez-Ramos L. Wan M. Weber H. Wei T. Wester A. White A. Wilkinson P. Wilson T. Wongjirad E. Worcester M. Worcester S. Yadav E. Yandel T. Yang L. Yates S. Yebes B. Yu H. Yu J. Yu B. Zamorano J. Zennamo C. Zhang
This is my paper

Pith reviewed 2026-06-26 00:57 UTC · model grok-4.3

classification ⚛️ physics.ins-det hep-ex
keywords TPB coatingwavelength shifterreflective platesliquid argon TPCneutrino detectorlight collectionSBNDphoton detection
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The pith

The SBND detector deploys 64 TPB-coated reflective plates on its cathode to increase and uniformize scintillation light collection.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper reports the design, production, and in-situ installation of 64 double-sided plates made from FR4, laminated with specular reflector film, and coated with 300 micrograms per square centimeter of tetraphenyl butadiene using physical vapor deposition. These plates sit on the cathode of the liquid argon time projection chamber and work with photomultiplier tubes and X-ARAPUCAs to collect more scintillation light while reducing variations across the detector volume. Pre-installation checks of deposited mass and surface profiles, together with early light-response data, confirm uniformity and support gains in triggering, calorimetry, and event positioning. The resulting coated area is stated to be the largest yet placed inside any neutrino detector.

Core claim

The central claim is that a wavelength-shifting reflective system of 64 double-sided plates was fabricated, protected from ambient light during handling, assembled between conductive meshes for high-voltage compatibility, and installed on the SBND cathode; mass and profilometry measurements validated the 300 μg/cm² TPB coating, and initial light-collection data showed high uniformity and response across the detector volume.

What carries the argument

Double-sided FR4 plates laminated with specular reflector film and coated with tetraphenyl butadiene (TPB) wavelength shifter, installed on the cathode and operated with the existing photon detection system.

If this is right

  • Light collection becomes more uniform across the full detector volume.
  • Triggering efficiency for neutrino interactions improves.
  • Calorimetry and three-dimensional position reconstruction gain from the added light information.
  • The mesh-mounted plate assembly maintains high-voltage compatibility inside the liquid argon volume.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same plate fabrication and coating sequence could be adapted for larger liquid argon detectors to address light-collection shortfalls.
  • Continued monitoring of light yield over the full run would test whether the protective handling steps preserved performance long-term.
  • The modular plate design between meshes suggests a route for retrofitting or upgrading photon systems in existing detectors.

Load-bearing premise

The TPB coating remains stable, uniform, and functional after installation and under normal detector operating conditions.

What would settle it

A later measurement that finds large non-uniformity in light yield or clear degradation in response after months of operation would show the coating did not perform as intended.

read the original abstract

We report on the design, production, and installation of a wavelength-shifting reflective system on the cathode of the Short-Baseline Near Detector (SBND), a liquid argon time projection chamber located along the Fermilab Booster Neutrino Beam. To increase and homogenize scintillation-light collection, 64 double-sided plates were fabricated from FR4, laminated with specular reflector film and coated with 300 $\mu$g/cm$^2$ of tetraphenyl butadiene (TPB) wavelength shifter using controlled physical vapor deposition. The coating uniformity was validated through dedicated measurements of deposited mass and profilometry studies. Because exposure to ambient blue/UV light could degrade the TPB, protective filtering and controlled storage conditions were implemented during handling and installation. The coated plates were assembled between conductive meshes for high-voltage compatibility and installed in situ during detector integration. This system constitutes the largest TPB-coated area deployed in a neutrino detector. It operates in conjunction with SBND's photon detection system, which consists of photomultiplier tubes and X-ARAPUCAs. Early light-collection measurements show high uniformity and light response across the detector, supporting improved triggering, calorimetry, and position reconstruction in SBND.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 0 minor

Summary. The manuscript presents the design, production, and installation of a wavelength-shifting reflective light enhancer system consisting of 64 double-sided plates for the cathode plane of the Short-Baseline Near Detector (SBND), a liquid argon time projection chamber. The plates are made from FR4, laminated with specular reflector film, and coated with 300 μg/cm² of tetraphenyl butadiene (TPB) using physical vapor deposition (PVD). Uniformity was validated using deposited mass measurements and profilometry. Protective measures against ambient light degradation were implemented during handling and installation. The plates were assembled with conductive meshes and installed in situ. The work claims this to be the largest TPB-coated area in any neutrino detector and reports early light-collection measurements indicating high uniformity and light response, which are expected to improve triggering, calorimetry, and position reconstruction when used with the detector's PMTs and X-ARAPUCAs.

Significance. This technical report documents a substantial engineering effort to scale up TPB coating for a neutrino detector, achieving what is described as the largest such coated area to date. The detailed description of the PVD process, quality control via mass and profilometry, and light-protection protocols during assembly and installation offers practical guidance for similar applications in other large LArTPCs. If the early uniformity data hold under full operating conditions, the system could meaningfully enhance light collection efficiency and homogeneity, thereby benefiting overall detector performance. The manuscript also highlights the integration with existing photon detection systems, providing a case study in detector upgrade or enhancement strategies.

major comments (1)
  1. [Abstract] Abstract: the statement that early light-collection measurements show 'high uniformity and light response' is presented without quantitative values, error bars, specific metrics, or comparison to baseline expectations. This limits evaluation of the supporting evidence for the claimed improvements in triggering, calorimetry, and position reconstruction.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading of the manuscript and for the recommendation of minor revision. We address the single major comment below.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the statement that early light-collection measurements show 'high uniformity and light response' is presented without quantitative values, error bars, specific metrics, or comparison to baseline expectations. This limits evaluation of the supporting evidence for the claimed improvements in triggering, calorimetry, and position reconstruction.

    Authors: We agree that the abstract statement would be more informative with quantitative support. The body of the manuscript already contains the relevant early light-collection data, including measured uniformity across the cathode plane and light-response values obtained with the installed system. In the revised version we will update the abstract to include the key numerical results (e.g., fractional variation in light yield and comparison to the no-reflector baseline) together with the associated uncertainties. revision: yes

Circularity Check

0 steps flagged

No circularity; factual engineering report with no derivations

full rationale

The paper is a technical report documenting the design, fabrication (FR4 plates with specular film and TPB coating via PVD), validation via mass and profilometry measurements, handling, assembly, and in-situ installation of 64 plates. All claims, including the largest TPB-coated area and early uniformity data, are supported directly by the described processes and measurements without any equations, fitted predictions, self-citations forming load-bearing chains, or derivations that reduce to inputs by construction. The stability assumption is tied explicitly to pre- and post-installation data rather than circular reasoning.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is an applied instrumentation paper with no theoretical free parameters, axioms, or new postulated entities.

pith-pipeline@v0.9.1-grok · 6802 in / 1234 out tokens · 30600 ms · 2026-06-26T00:57:00.787660+00:00 · methodology

discussion (0)

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Reference graph

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