arxiv: 2604.03059 · v2 · submitted 2026-04-03 · ⚛️ physics.ins-det

Recognition: no theorem link

The Darkside-20k Data Acquisition System

Fabio Acerbi , Pushparaj Adhikari , Paolo Agnes , Iftikhar Ahmad , Sebastiano Albergo , Ivone F.M. Albuquerque , Thomas Olling Alexander , Andrew Knight Alton

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Pierre-Andre Amaudruz Gioacchino Alex Anastasi Michele Angiolilli Elena Aprile David J. Auty Maximo Ave Pernas Oscar Azzolini Henning Olling Back Zoe Balmforth Ana Isabel Barrado Olmedo Pierre Barrillon Giovanni Batignani Swadheen Bharat Pritindra Bhowmick Sofia Blua Valerio Bocci Walter Bonivento Bianca Bottino Mark G. Boulay Titanilla Braun Andrzej Buchowicz Severino Bussino Jose Busto Matteo Cadeddu Mariano Cadoni Roberta Calabrese Vincenzo Camillo Alessio Caminata Nicola Canci Andrea Capra Mauro Caravati Miguel Cardenas-Montes Nicola Cargioli Marco Carlini Paolo Castello Paolo Cavalcante Susana Cebrian Alexander Chepurnov Sarthak Choudhary Luisa Cifarelli Yann Coadou Ivan Coarasa Valentina Cocco Estefania Conde Vilda Lucia Consiglio Harrison Coombes Andre Filipe Ventura Cortez Barbara S. Costa Milena Czubak Saverio D'Auria Manuel Dionisio Da Rocha Rolo Alexander Dainty Giovanni Darbo Stefano Davini Riccardo de Asmundis Sandro De Cecco Marzio De Napoli Giulio Dellacasa Alexander Derbin Lea Di Noto Philippe Di Stefano Daniel Diaz Mairena Carlo Dionisi Grigory Dolganov Francesca Dordei Aaron Elersich Emma Ellingwood Tyler Erjavec Niamh Fearon Marta Fernandez Diaz Luca Ferro Andrea Ficorella Giuliana Fiorillo Dylon Fleming Paolo Franchini Davide Franco Heriques Frandini Gatti Federico Gabriele Devidutta Gahan Cristiano Galbiati Grzegorz Galinski Giacomo Gallina Marco Garbini Pablo Garcia Abia Andrzej Gawdzik Graham Kurt Giovanetti Alberto Gola Luca Grandi Gianfrancesco Grauso Giovanni Grilli di Cortona Alexey Grobov Maxim Gromov Julian Guerrero Canovas Marisa Gulino Samuel Belayneh Habtemariam Brianne Rae Hackett Aksel Hallin Malgorzata Haranczyk Timothee Hessel Celin Hidalgo James Hollingham Sosuke Horikawa Jie Hu Fabrice Hubaut Daniel Huff Theo Hugues Andrea Ianni Valerio Ippolito Ako Jamil Chris Jillings Rijeesh Keloth Nikolas Kemmerich Ashlea Kemp Kaori Kondo George Korga Lucy Kotsiopoulou Seraphim Koulosousas Pablo Kunze Michael Kuss Marcin Kuzniak Maciej Kuzwa Marco La Commara Michela Lai Emmanuel Le Guirriec Elizabeth Leason Alfiero Leoni Lance Lidey John D Lipp Marcello Lissia Ludovico Luzzi Olga Lychagina Oliver Macfadyen Janna Machts Igor Machulin Szymon Manecki Ioannis Manthos Andrea Marasciulli Stefano Maria Mari Camillo Mariani Jelena Maricic Maria Martinez Giuseppe Matteucci Konstantinos Mavrokoridis Arthur B. McDonald Luo Meng Stefano Merzi Andrea Messina Radovan Milincic Graham Miller Saverio Minutoli Ankush Mitra Jocelyn Monroe Matteo Morrocchi Abdulrahman Morsy Valentina Muratova Michael Murra Carlo Muscas Paolo Musico Rosario Nania Marzio Nessi Grzegorz Nieradka Konstantinos Nikolopoulos Evangelia Nikoloudaki Jaroslaw Nowak Konstantin Olchanski Andrey Oleinik Paolo Organtini Alfonso Ortiz de Solorzano Anantha Padmanabhan Marco Pallavicini Luciano Pandola Emilija Pantic Eugenio Paoloni Danial Papi Byungju Park Grzegorz Pastuszak Giovanni Paternoster Riccardo Pavarani Alec Peck Paolo Attilio Pegoraro Krzysztof Pelczar Ramon Perez Vicente Pesudo Stefano Piacentini Noemi Pino Guillaume Plante Andrea Pietro Pocar Stephen Pordes Pascal Pralavorio Elettra Preosti Darren Price George Prior Manuel Pronesti Sebastiana Puglia Maria Cecilia Queiroga Bazetto Fabrizio Raffaelli Francesco Ragusa Yorck Ramachers Alejandro Ramirez Sudikshan Ravinthiran Marco Razeti Andrew Lee Renshaw Aras Repond Marco Rescigno Silvia Resconi Fabrice Retiere Ash Ritchie-Yates Angelo Rivetti Adam Roberts Conner Roberts Diego Rodriguez Rodas Giovanni Rogers Luciano Romero Matteo Rossi Dmitry Rudik James Runge Maria Adriana Sabia Camilla Salerno Paolo Salomone Simone Sanfilippo Daria Santone Roberto Santorelli Edivaldo M. Santos Isobel Sargeant Maria Luisa Sarsa Claudio Savarese Eugenio Scapparone Fred Schuckman Dmitriy Semenov Carmen Seoane Michela Sestu Veronika Shalamova Sanjay Sharma Poudel Marino Simeone Peter Skensved Mikhail Skorokhvatov Taisiia Smirnova Ben Smith Robert Smith Franco Spadoni Martin Spangenberg Arianna Steri Vincenzo Stornelli Simone Stracka Allan Sung Clea Sunny Yury Suvorov Andrzej M Szelc Oscar Taborda Benjamin Tam Roberto Tartaglia Alan Taylor Jonathan Taylor Gemma Testera Kevin Thieme Angus Thompson Sebastian Torres-Lara Alessia Tricomi Sara Tullio Evgeniy Unzhakov Marie Van Uffelen Pedro Ventura Guillermo Vera Diaz Simon Viel Alina Vishneva Bruce Vogelaar Joost Vossebeld Bansari Vyas Masayuki Wada Marek Bohdan Walczak Yi Wang Shawn Westerdale Laurie Williams Marcin Marian Wojcik Mariusz Wojcik Changgen Yang Jilong Yin Azam Zabihi Paul Zakhary Andrea Zani Haoxiang Zhan Yongpeng Zhang Antonino Zichichi Grzegorz Zuzel

Authors on Pith no claims yet

Pith reviewed 2026-05-13 19:09 UTC · model grok-4.3

classification ⚛️ physics.ins-det

keywords DarkSide-20kDAQSiPMliquid argonWIMP searchdigitizerstriggerlessdata reduction

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The pith

DarkSide-20k's DAQ digitizes all 2720 SiPM channels continuously and reduces data online after quadrant-scale validation.

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

The paper presents the data acquisition architecture for DarkSide-20k, a liquid-argon time projection chamber built for a background-free WIMP search. The system performs triggerless, continuous waveform capture at high single-photoelectron efficiency while applying real-time processing to shrink the data volume for storage. Timing across 48 commercial digitisers is maintained by custom boards locked to a rubidium reference, and waveforms are segmented and assembled by a farm of processors into detector-wide collections. A full quarter of the hardware, called the Quadrant, was assembled and run at TRIUMF with simultaneous pulses, confirming sustained readout above expected physics rates and stable long-term operation.

Core claim

The DAQ uses CAEN VX2745 digitisers running custom FPGA firmware for continuous digitisation, with Global and Crate Data Manager boards distributing a phase-aligned clock from a disciplined rubidium standard. Waveform segments are processed in real time by Front End Processor machines and then distributed across Time Slice Processors that reconstruct events, classify them, and apply further reduction before storage.

What carries the argument

The Quadrant prototype, one quarter of the final system, that integrates 48 digitisers, custom synchronisation boards, and a processor farm to achieve continuous, synchronised readout and online data reduction.

If this is right

Continuous triggerless digitisation with high single-photoelectron efficiency becomes feasible for the full 2720-channel detector.
Real-time waveform processing organises data into complete-detector collections suitable for event reconstruction and classification.
Online reduction brings the data volume down to levels manageable for long-term storage and offline analysis.
The synchronisation scheme using rubidium-derived clocks keeps timing stable across the entire array for extended periods.

Where Pith is reading between the lines

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

The same continuous-readout and real-time reduction approach could be adapted for other noble-liquid experiments that must record rare events without dead time.
If the artificial-pulse results hold for genuine low-energy signals, the architecture would support background rejection at the level required for a background-free search.
The quarter-scale test implies that the design can be scaled without introducing new rate or synchronisation bottlenecks.

Load-bearing premise

Performance measured with artificial simultaneous pulses on the quadrant prototype will translate directly to full-scale operation with real physics events, backgrounds, and all 2720 channels active.

What would settle it

A run of the complete detector in which data loss or rate shortfalls appear once all channels record actual scintillation signals rather than test pulses.

read the original abstract

DarkSide-20k is a WIMP search experiment using liquid argon as a target, designed to perform a background-free search for dark matter with unprecedented sensitivity, and is currently under construction at INFN Laboratori Nazionali del Gran Sasso, Italy. The detector comprises a dual-phase Time Projection Chamber complemented with external veto systems and is equipped with a total of 2720 SiPM-based readout channels. This work presents the DAQ system designed for DarkSide-20k. The system is capable of continuous, triggerless digitisation of the waveforms with high single-photoelectron detection efficiency and online processing, ensuring data reduction for long-term storage. The DarkSide-20k DAQ system employs commercial CAEN VX2745 digitisers with custom FPGA firmware implementation. Timing and synchronisation across all 48 digitisers are provided by custom Global and Crate Data Manager boards distributing a phase-aligned clock derived from a disciplined rubidium standard. Waveform segments are processed in real time by Front End Processor machines. Data are organised into collections containing whole detector information and distributed across a farm of Time Slice Processors for event reconstruction, classification, and further reduction before storage and offline analysis. A full "Quadrant" of the system, corresponding to one quarter of the final DAQ, has been assembled and validated at TRIUMF laboratory in Canada. The Quadrant has been stress-tested with simultaneous pulses and demonstrated sustained digitizer readout exceeding expected physics rates and stable long-term performance.

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.

Desk Editor's Note private letter to a colleague

This is a straightforward technical report on the DarkSide-20k DAQ that documents a working quadrant prototype with concrete rate and stability numbers, but full-scale performance with real events remains extrapolated.

read the letter

The paper lays out the DAQ for DarkSide-20k in clear terms: 2720 SiPM channels, CAEN VX2745 digitisers running custom FPGA firmware for continuous digitization, custom global and crate managers for clock distribution from a rubidium standard, and a two-stage processing chain that reduces data before storage. The quadrant test at TRIUMF is the main result. They ran simultaneous pulses across the quarter-scale setup and showed sustained readout above the expected physics rates with no dropouts over long periods. That part is solid and directly supports the claim that the hardware can keep up at that scale. The synchronization scheme and data organization into time slices also look practical for a detector of this size. What is new is the specific combination for this experiment—the firmware choices, the exact channel count, and the measured performance on the assembled quadrant. Those details are not in the earlier literature they cite. The soft spot is the test conditions. Simultaneous artificial pulses stress bandwidth but do not match the sparse, stochastic arrival times or the spatial correlations of real LAr TPC events. The paper does not report measurements with actual physics-like pulses or with all 2720 channels live, so the load on the time-slice processors and the effectiveness of the online reduction at full scale are still projections. Minor gaps include limited discussion of how the system would handle edge cases like high-background periods or partial board failures. This paper is for people who build or maintain DAQ systems for large noble-liquid detectors. Anyone planning similar hardware would find the firmware and synchronization sections useful as a reference. It deserves peer review because the prototype results are concrete and the description is detailed enough for others to assess or replicate the approach.

Referee Report

1 major / 2 minor

Summary. The manuscript presents the design of the DarkSide-20k DAQ system for a 2720-channel SiPM readout in a liquid argon TPC dark matter detector. Key elements include CAEN VX2745 digitisers with custom FPGA firmware, Global and Crate Data Manager boards for synchronization using a rubidium standard, Front End Processors for real-time waveform processing, and a farm of Time Slice Processors for event reconstruction and data reduction. Validation is provided through assembly and stress-testing of a full quadrant prototype at TRIUMF, which showed sustained digitizer readout exceeding expected physics rates under simultaneous pulses and long-term stability.

Significance. If the performance claims hold, this DAQ system is significant for enabling the high-sensitivity, background-free WIMP search in DarkSide-20k by providing continuous, triggerless digitization and efficient online data reduction. The prototype test with commercial hardware and custom firmware is a concrete strength, demonstrating practical implementation and stability.

major comments (1)

[Quadrant validation] The stress-testing described uses simultaneous artificial pulses on the quadrant prototype to demonstrate sustained readout above expected rates. However, this does not account for the stochastic arrival times, spatial correlations, or background-induced coincidences in real physics events. Since the central claim of the system's capability for full-scale operation relies on this test, additional justification or simulation of scaling to 2720 channels with realistic event distributions is needed to support the conclusions.

minor comments (2)

[Abstract] The phrase 'long-term performance' is used without specifying the duration or quantitative stability metrics; these details should be provided in the main text for clarity.
[Introduction or methods] Consider adding a reference to prior DarkSide DAQ systems or similar experiments for context on the evolution of the design.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the constructive review of our manuscript on the DarkSide-20k DAQ system. We address the major comment below.

read point-by-point responses

Referee: The stress-testing described uses simultaneous artificial pulses on the quadrant prototype to demonstrate sustained readout above expected rates. However, this does not account for the stochastic arrival times, spatial correlations, or background-induced coincidences in real physics events. Since the central claim of the system's capability for full-scale operation relies on this test, additional justification or simulation of scaling to 2720 channels with realistic event distributions is needed to support the conclusions.

Authors: We appreciate the referee's observation. The simultaneous pulses were deliberately selected to impose the maximum instantaneous load on the digitizers, data links, and Front End Processors, with all 680 channels in the quadrant firing concurrently. This exceeds the peak throughput that would arise from stochastic event arrivals, spatial correlations, or background coincidences in actual physics data, which distribute the readout demand over time. Such correlations primarily affect the downstream Time Slice Processors during event reconstruction rather than the front-end readout bandwidth validated by the test. The full system consists of four identical, independent quadrants sharing only the global clock; therefore, the sustained performance measured on one quadrant scales directly by a factor of four to the complete 2720-channel detector. We will add a short clarifying paragraph in the revised manuscript to make this worst-case rationale and modular scaling explicit. revision: partial

Circularity Check

0 steps flagged

No circularity: direct hardware description with empirical prototype tests

full rationale

The paper is a technical description of the DarkSide-20k DAQ hardware, firmware, synchronization, and data flow, plus results from a quadrant-scale prototype tested with artificial simultaneous pulses. No derivations, equations, fitted parameters, predictions, or first-principles results are claimed. The performance statements rest on direct measurements rather than any self-referential logic, self-citation chains, or renaming of inputs. The quadrant-to-full-scale extrapolation is an engineering assumption, not a circular derivation. This matches the default expectation of no significant circularity for a non-theoretical instrumentation paper.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is an engineering implementation paper with no mathematical derivations, fitted parameters, or postulated physical entities. The central claims rest on hardware design choices and empirical test results rather than axioms or free parameters.

pith-pipeline@v0.9.0 · 6963 in / 1121 out tokens · 43478 ms · 2026-05-13T19:09:37.221017+00:00 · methodology

discussion (0)

Reference graph

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