Pith. sign in

REVIEW 37 references

Commissioning of the 2.6 m tall two-phase xenon time projection chamber of Xenoscope

T0 review · reviewed 2026-08-12 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗ Review JSON

Pith's one-line read Xenoscope's 2.6 m tall xenon TPC was commissioned and detected correlated light and charge signals from cosmic muons near the top of the detector.

arxiv 2411.08022 v2 pith:PAITPYKL submitted 2024-11-12 physics.ins-det astro-ph.IM

M. Adrover , M. Babicz , L. Baudis , Y. Biondi , A. Bismark , C. Capelli , A. P. Cimental Chávez , J. J. Cuenca-García
show 9 more authors
M. Galloway F. Girard F. Jörg S. Ouahada R. Peres F. Piastra M. Rajado Silva D. Ramírez García C. Wittweg
This is my paper · ORCID
classification physics.ins-detastro-ph.IM
keywords xenonchambercommissioningelectronliquidprojectiontalltime
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

Xenoscope is a test facility at the University of Zurich built to prove that a very tall liquid xenon detector can work. It contains a 2.6 metre tall time projection chamber, or TPC, filled with about 360 kg of liquid xenon. In such a detector, a particle hitting the xenon produces a quick flash of light, called S1, and a cloud of electrons. The electrons are pushed upward by an electric field, cross into the xenon gas above the liquid, and make a second, longer flash called S2. The time between the flashes reveals where the particle interacted; the size of the flashes reveals how much energy it deposited.

The paper describes how the team built and switched on this TPC. They filled it with xenon, set the electric fields, and watched the liquid level with capacitive sensors. After several weeks of carefully raising the high voltage, they saw S1 and S2 signals from cosmic muons passing through the top of the detector. Because the xenon purification system was being repaired, they could only see events close to the liquid surface; they did not yet demonstrate electron drift across the full 2.6 m height. They are open about this limit and plan to do the full drift measurement in 2025.

This is not a new physics discovery. It is an engineering milestone for the proposed XLZD observatory, which would use a much larger xenon TPC to search for dark matter and study neutrinos. Success here means the long-drift part of that design is realistic; failure would have forced a redesign. The next steps are to purify the xenon and measure how electron clouds spread as they drift over the full height.

Extended reading notes

Core claim

Section 5 states: 'We observed correlated scintillation and ionisation signals from cosmic muon interactions near the top of the detector, validating the dual-phase TPC working mode.' If true, the 2.6 m tall TPC, field cage, HV system, liquid level control, and SiPM array operate together as a two-phase detector, which is the prerequisite for future drift and diffusion measurements.

Load-bearing premise

The classification of the observed wide pulses as S2 electroluminescence from charge drifted out of the liquid relies on the waveform shape and on coincidence with the plastic scintillator trigger, but only a single example event is shown (Figure 7). If those wide pulses were produced by another mechanism (for example, direct scintillation of the muon in the gas, electronic cross-talk, or a discharge), the conclusion that the dual-phase TPC is working could be wrong. The paper does not provide an event rate, a background estimate, or an independent pulse-shape validation for this identification.

Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Assumptions & free parameters 1 free parameters · 3 assumptions · 0 invented entities

The central claim is an observation, not a derived number, so no fitted parameter is load-bearing. The only fitted value is the long-level-metre calibration line, which is a sensor calibration. The axioms are standard LXe TPC assumptions about signal formation and level metering; none was introduced ad hoc to force the result. No new physical entities are postulated.

free parameters (1)
  • LLM capacitance-to-height calibration slope = 0.745 pF/cm with intercept 130.4 pF
    Fitted to the spacer-ring plateau positions in Section 4.1 to convert LLM capacitance into liquid height; it is a sensor calibration and does not determine whether S1-S2 signals were observed.
assumptions (3)
  • domain assumption Two-phase TPC signal model: prompt scintillation produces S1 and electroluminescence in the gas phase produces S2.
    Invoked in Section 4.4 to interpret the observed waveforms as S1-S2 events; standard for LXe TPCs and not independently re-derived here.
  • domain assumption Capacitive level metres convert capacitance to liquid height using known LXe/GXe dielectric constants and a fitted spacer-ring calibration.
    Used in Section 4.1 to set the liquid level about 6 mm above the gate; relies on refs [25-27] and on the linear fit to spacer-ring plateaus.
  • domain assumption The plastic scintillator panel coincidence identifies cosmic muons crossing the top of the TPC.
    Used in Section 4.4 to attribute the observed S1-S2 events to muons; no independent muon signature such as a rate comparison is provided.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Commissioning of the 2.6 m tall two-phase xenon time projection chamber of Xenoscope." pith.science (2026). https://pith.science/paper/PAITPYKL

@misc{pith2026241108022,
  author       = {Pith},
  title        = {Pith review of: Commissioning of the 2.6 m tall two-phase xenon time projection chamber of Xenoscope},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/PAITPYKL}},
  note         = {Machine review of arXiv:2411.08022}
}
abstract

Xenoscope is a demonstrator for a next-generation xenon-based observatory for astroparticle physics, as proposed by the XLZD (XENON-LUX-ZEPLIN-DARWIN) collaboration. It houses a 2.6 m tall, two-phase xenon time projection chamber (TPC), in a cryostat filled with $\sim$ 360 kg of liquid xenon. The main goals of the facility are to demonstrate electron drift in liquid xenon over this distance, to measure the electron cloud transversal and longitudinal diffusion, as well as the optical properties of the medium. In this work, we describe in detail the construction and commissioning of the TPC and report on the observation of light and charge signals with cosmic muons.

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

37 extracted references · 21 canonical work pages

  1. [1]

    Baudis,Dual-phase xenon time projection chambers for rare-event searches, Phil

    L. Baudis,Dual-phase xenon time projection chambers for rare-event searches, Phil. Trans. Roy. Soc. Lond. A382(2023) 20230083, [2311.05320]

    arXiv 2023

  2. [2]

    Navas et al.,Review of particle physics,Phys

    Particle Data Groupcollaboration, S. Navas et al.,Review of particle physics,Phys. Rev. D110 (2024) 030001

    2024

  3. [3]

    Aalbers et al.,Background determination for the LUX-ZEPLIN dark matter experiment, Phys

    LZ collaboration, J. Aalbers et al.,Background determination for the LUX-ZEPLIN dark matter experiment, Phys. Rev. D108 (2023) 012010, [2211.17120]

    arXiv 2023

  4. [4]

    Meng et al.,Dark Matter Search Results from the PandaX-4T Commissioning Run,Phys

    PandaX-4Tcollaboration, Y. Meng et al.,Dark Matter Search Results from the PandaX-4T Commissioning Run,Phys. Rev. Lett.127 (2021) 261802, [2107.13438]

    arXiv 2021

  5. [5]

    Aprile et al.,The XENONnT dark matter experiment,Eur

    XENONcollaboration, E. Aprile et al.,The XENONnT dark matter experiment,Eur. Phys. J. C84 (2024) 784, [2402.10446]

    arXiv 2024

  6. [6]

    Aalbers et al.,DARWIN: towards the ultimate dark matter detector,JCAP 11(2016) 017, [1606.07001]

    DARWINcollaboration, J. Aalbers et al.,DARWIN: towards the ultimate dark matter detector,JCAP 11(2016) 017, [1606.07001]

    arXiv 2016

  7. [7]

    Abdukerim et al.,PandaX-xT: a Multi-ten-tonne Liquid Xenon Observatory at the China Jinping Underground Laboratory, 2402.03596

    PandaXcollaboration, A. Abdukerim et al.,PandaX-xT: a Multi-ten-tonne Liquid Xenon Observatory at the China Jinping Underground Laboratory, 2402.03596

    arXiv

  8. [8]

    Baudis,DARWIN/XLZD: A future xenon observatory for dark matter and other rare interactions, Nucl

    L. Baudis,DARWIN/XLZD: A future xenon observatory for dark matter and other rare interactions, Nucl. Phys. B1003 (2024) 116473, [2404.19524]. – 17 –

    arXiv 2024

Show all 37 references
  1. [9]

    Aalbers et al.,The XLZD Design Book: Towards the Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics, 2410.17137

    XLZD collaboration, J. Aalbers et al.,The XLZD Design Book: Towards the Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics, 2410.17137

  2. [10]

    Aalbers et al.,Solar neutrino detection sensitivity in DARWIN via electron scattering, Eur

    DARWINcollaboration, J. Aalbers et al.,Solar neutrino detection sensitivity in DARWIN via electron scattering, Eur. Phys. J. C80(2020) 1133, [2006.03114]

    2020 arXiv

  3. [11]

    Aprile et al.,First Measurement of Solar8B Neutrinos via Coherent Elastic Neutrino-Nucleus Scattering with XENONnT, 2408.02877

    XENONcollaboration, E. Aprile et al.,First Measurement of Solar8B Neutrinos via Coherent Elastic Neutrino-Nucleus Scattering with XENONnT, 2408.02877

  4. [12]

    Bo et al.,First Indication of Solar8B Neutrino Flux through Coherent Elastic Neutrino-Nucleus Scattering in PandaX-4T, 2407.10892

    PandaXcollaboration, Z. Bo et al.,First Indication of Solar8B Neutrino Flux through Coherent Elastic Neutrino-Nucleus Scattering in PandaX-4T, 2407.10892

    arXiv

  5. [13]

    Aprile et al.,Double-Weak Decays of124Xe and136Xe in the XENON1T and XENONnT Experiments,Phys

    XENONcollaboration, E. Aprile et al.,Double-Weak Decays of124Xe and136Xe in the XENON1T and XENONnT Experiments,Phys. Rev. C106 (2022) 024328, [2205.04158]

    2022 arXiv

  6. [14]

    Brown et al.,PANCAKE: a large-diameter cryogenic test platform with a flat floor for next generation multi-tonne liquid xenon detectors,JINST 19 (2024) P05018, [2312.14785]

    A. Brown et al.,PANCAKE: a large-diameter cryogenic test platform with a flat floor for next generation multi-tonne liquid xenon detectors,JINST 19 (2024) P05018, [2312.14785]

    2024 arXiv

  7. [15]

    Baudis and et al.,Design and construction of Xenoscope — a full-scale vertical demonstrator for the DARWIN observatory,JINST 16(2021) P08052, [2105.13829]

    L. Baudis and et al.,Design and construction of Xenoscope — a full-scale vertical demonstrator for the DARWIN observatory,JINST 16(2021) P08052, [2105.13829]

    2021 arXiv

  8. [16]

    Baudis et al.,Electron transport measurements in liquid xenon with Xenoscope, a large-scale DARWIN demonstrator,Eur

    L. Baudis et al.,Electron transport measurements in liquid xenon with Xenoscope, a large-scale DARWIN demonstrator,Eur. Phys. J. C83(2023) 717, [2303.13963]

    2023 arXiv

  9. [17]

    Mehrteilige lagervorrichtung und stützsegment

    F. Girard and K. Thieme, “Mehrteilige lagervorrichtung und stützsegment.” 2022. Patent No. CH718439A2, Switzerland,https://www.swissreg.ch/srclient/faces/jsp/patent/ sr300.jsp?language=en&section=pat&id=CH718439

    2022

  10. [18]

    Mehrteilige lagervorrichtung und stützsegment

    F. Girard and K. Thieme, “Mehrteilige lagervorrichtung und stützsegment.” 2022. Patent No. 20 2021 101 412.1, Germany,https://depatisnet.dpma.de/DepatisNet/depatisnet?action= bibdat&docid=DE202021101412U1

    2022

  11. [19]

    S. G. Sammartano, I. Wevers, G. Bregliozzi and P. Chiggiato,Outgassing rates of PEEK, Kapton® and Vespel®foils,CERN technical note, CERN-ACC-NOTE-2020-0039(2020)

    2020

  12. [20]

    Ventura, G

    G. Ventura, G. Bianchini, E. Gottardi, I. Peroni and A. Peruzzi,Thermal expansion and thermal conductivity of torlon at low temperatures, Cryogenics39 (1999) 481–484

    1999

  13. [21]

    LZ collaboration, D. S. Akerib et al.,The LUX-ZEPLIN (LZ) Experiment,Nucl. Instrum. Meth. A953 (2020) 163047, [1910.09124]

    2020 arXiv

  14. [22]

    Datasheet: Shielded hv cables in various voltage classes up to 200 kv

    Heinzinger, “Datasheet: Shielded hv cables in various voltage classes up to 200 kv.”https: //www.heinzinger.com/assets/uploads/downloads/Datenblatt_HVC_ENG_2024.pdf

  15. [23]

    Datasheet: Advanced Ceramic-To-Metal and Glass-Ceramic Sealing Technology

    CeramTec, “Datasheet: Advanced Ceramic-To-Metal and Glass-Ceramic Sealing Technology.” https://www.ceramtec-group.com/fileadmin/user_upload/Corporate/11_Downloads/ 05_Ceramaseal/CeramTec_us_ceramaseal_feedthroughs.pdf

  16. [24]

    Watson, I

    J. Watson, I. Olcina, J. Soria, D. N. McKinsey, S. Kravitz, E. E. Deck et al.,Study of dielectric breakdown in liquid xenon with xebra: The xenon breakdown apparatus,Review of Scientific Instruments94 (1, 2023)

    2023

  17. [25]

    Marcoux,Dielectric constants and indices of refraction of Xe, Kr, and Ar,Canadian Journal of Physics48 (1970) 244–245

    J. Marcoux,Dielectric constants and indices of refraction of Xe, Kr, and Ar,Canadian Journal of Physics48 (1970) 244–245

    1970

  18. [26]

    R. L. Amey and R. H. Cole,Dielectric Constants of Liquefied Noble Gases and Methane,The Journal of Chemical Physics40 (June, 2004) 146–148

    2004

  19. [27]

    Sawada, J

    R. Sawada, J. Kikuchi, E. Shibamura, M. Yamashita and T. Yoshimura,Capacitive level meter for liquid rare gases,Cryogenics43(Aug., 2003) 449–450. – 18 –

    2003

  20. [28]

    F. M. L. Van Der Goes and G. C. M. Meijer,A Universal Transducer Interface for Capacitive and Resistive Sensor Elements, inSmart Sensor Interfaces(J. H. Huijsing and G. C. M. Meijer, eds.), pp. 87–98. Springer US, Boston, MA, 1997. DOI

    1997

  21. [29]

    Datasheet: Universal Transducer Interface

    Smartec, “Datasheet: Universal Transducer Interface.” 2016. www.smartec-sensors.eu/cms/media/Datasheets/UTI_interface/UTI_datasheet.pdf

    2016

  22. [30]

    Peres,SiPM array of Xenoscope, a full-scale DARWIN vertical demonstrator,JINST 18(2023) C03027, [2303.15300]

    R. Peres,SiPM array of Xenoscope, a full-scale DARWIN vertical demonstrator,JINST 18(2023) C03027, [2303.15300]

    2023 arXiv

  23. [31]

    Arneodo and et al.,Cryogenic readout for multiple VUV4 Multi-Pixel Photon Counters in liquid xenon,Nucl

    F. Arneodo and et al.,Cryogenic readout for multiple VUV4 Multi-Pixel Photon Counters in liquid xenon,Nucl. Instrum. Meth. A893 (2018) 117–123, [1707.08004]

    2018 arXiv

  24. [32]

    https://www.vacom.net/en/home.html

    VACOM. https://www.vacom.net/en/home.html

  25. [33]

    Aprile,The XENON1T Dark Matter Search Experiment,Springer Proc

    XENONcollaboration, E. Aprile,The XENON1T Dark Matter Search Experiment,Springer Proc. Phys.148(2013) 93–96, [1206.6288]

    2013 arXiv

  26. [34]

    https://www.accuglassproducts.com/

    Accu-Glass Products. https://www.accuglassproducts.com/

  27. [35]

    V1724 flash ADC

    CAEN, “V1724 flash ADC.”https://www.caen.it/products/v1724/

  28. [36]

    Peres,Pylars v0.3.1, 2024

    R. Peres,Pylars v0.3.1, 2024. 10.5281/zenodo.13756802

    2024 doi

  29. [37]

    Girard,Design, Construction, and Operation of Xenoscope and Photosensor Characterisation for the DARWIN Observatory

    F. Girard,Design, Construction, and Operation of Xenoscope and Photosensor Characterisation for the DARWIN Observatory. PhD thesis, University of Zurich, Zurich, Switzerland, 2023. – 19 –

    2023

Pith tools

Reviewed August 12, 2026 · model on record in the stance chip above.