{
  "abstract": "LiquidO detectors confine scintillation light near its point of production by stochastic scattering in an opaque medium and collect it with a lattice of wavelength-shifting (WLS) fibers. The elementary signal of such a detector is the point-like sub-MeV energy deposition, yet the response to that signal at the center of the detector volume has not been measured against an event-by-event ground truth. To close this gap, we couple BPULSE, a 4-liter prototype LiquidO detector, to a Compton-coincidence calibration setup that selects electron recoils of known energy on a constrained beam axis. The prototype is a 160 mm cube of opaque scintillator with 64 WLS fibers in alternating orthogonal layers at a 20 mm pitch, read out by silicon photomultipliers. Compton scatters of collimated gamma-ray beams from $^{137}$Cs and $^{60}$Co sources are tagged by a NaI(Tl) spectrometer. For 373.4 keV electrons, tagged from $90^{\\circ}$ scatters of the $^{137}$Cs beam, the detector collects $19.04 \\pm 0.07$ photoelectrons (p.e.). Across four operating points, the two sources at two scattering angles, it responds linearly at $48.3 \\pm 1.5$ p.e./MeV. The energy resolution of $(23.4 \\pm 0.4)\\%$ matches the Poisson statistics of the detected photoelectrons. Collection at both fiber ends and larger sensors would raise the light yield of this target to an estimated 108-124 p.e./MeV. Center-of-mass reconstruction locates each recoil to the width of the delivered 20 mm beam spot, which bounds the intrinsic localization of the detector from above. The arrival time response sets a lower bound of 1.5 ns on the single-scatter start time at the observed $\\approx 19$ p.e. light level. This single-scatter response is the building block for reconstructing multi-site events. It constrains the light collection, confinement, and timing models on which reconstruction in future LiquidO detectors will rest.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.18849",
  "author_total": 92,
  "authors": [
    {
      "name": "LiquidO Collaboration"
    },
    {
      "name": "S. Katz"
    },
    {
      "name": "J. T. Moffatt"
    },
    {
      "name": "G. Wendel"
    },
    {
      "name": "D. F. Cowen"
    },
    {
      "name": "I. Jovanovic"
    },
    {
      "name": "S. Schoppmann"
    },
    {
      "name": "A. S. Wilhelm"
    },
    {
      "name": "J. Apilluelo"
    },
    {
      "name": "L. Asquith"
    },
    {
      "name": "N. P. Barradas"
    },
    {
      "name": "J. L. Beney"
    },
    {
      "name": "M. Berberan e Santos"
    },
    {
      "name": "X. de la Bernardie"
    },
    {
      "name": "T. J. C. Bezerra"
    },
    {
      "name": "M. Bongrand"
    },
    {
      "name": "C. Bourgeois"
    },
    {
      "name": "D. Breton"
    },
    {
      "name": "J. Busto"
    },
    {
      "name": "A. Cabrera"
    },
    {
      "name": "A. Cadiou"
    },
    {
      "name": "E. Calvo"
    },
    {
      "name": "M. de Carlos Generowicz"
    },
    {
      "name": "B. J. Cattermole"
    },
    {
      "name": "E. Chauveau"
    },
    {
      "name": "M. Chen"
    },
    {
      "name": "P. Chimenti"
    },
    {
      "name": "S. Kr. Das"
    },
    {
      "name": "S. Dusini"
    },
    {
      "name": "A. Earle"
    },
    {
      "name": "M. Felizardo"
    },
    {
      "name": "C. Frigerio Martins"
    },
    {
      "name": "J. Galán"
    },
    {
      "name": "J. A. García"
    },
    {
      "name": "A. Gibson-Foster"
    },
    {
      "name": "C. Girard-Carillo"
    },
    {
      "name": "J. J. Gómez-Cadenas"
    },
    {
      "name": "W. C. Griffith"
    },
    {
      "name": "K. Groomes"
    },
    {
      "name": "M. Guitière"
    },
    {
      "name": "F. Haddad"
    },
    {
      "name": "J. Hartnell"
    },
    {
      "name": "A. Holin"
    },
    {
      "name": "I. G. Irastorza"
    },
    {
      "name": "W. Keck"
    },
    {
      "name": "A. Kling"
    },
    {
      "name": "L. Koch"
    },
    {
      "name": "J. F. Le Du"
    },
    {
      "name": "F. Lefevre"
    },
    {
      "name": "P. Loaiza"
    },
    {
      "name": "J. A. Lock"
    },
    {
      "name": "T. Lux"
    },
    {
      "name": "G. Luzón"
    },
    {
      "name": "J. Maalmi"
    },
    {
      "name": "J. P. Malhado"
    },
    {
      "name": "F. Mantovani"
    },
    {
      "name": "J. G. Marques"
    },
    {
      "name": "C. Marquet"
    },
    {
      "name": "M. Martínez"
    },
    {
      "name": "D. Navas-Nicolás"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5xqh5bye49rmn.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.18849",
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  "id": "5xqh5bye49rmn",
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  "landing_url": "https://arxiv.org/abs/2610.18849",
  "language": "en",
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": "CC0-1.0",
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  "pdf_url": "https://arxiv.org/pdf/2610.18849",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-13",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5xqh5bye49rmn.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:11Z",
      "native_id": "2610.18849",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.18849"
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  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.ins-det",
      "subfield": "applied-instrumentation"
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  ],
  "title": "Energy, vertex, and time response of a LiquidO detector with an opaque-scintillator target to Compton-tagged electrons",
  "title_text": "Energy, vertex, and time response of a LiquidO detector with an opaque-scintillator target to Compton-tagged electrons",
  "type": "preprint",
  "updated_at": "2026-11-05T12:20:12Z",
  "url": "https://research.draconitic.com/paper/5xqh5bye49rmn",
  "venue": "arXiv",
  "versions": []
}