Pith. sign in

REVIEW 1 major objections 5 minor 37 references

Ultra-sensitive radon assay using an electrostatic chamber in a recirculating system

T0 review · 1 major / 5 minor · reviewed 2026-08-16 · deepseek-v4-flash

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

Pith's one-line read The paper claims a closed, continuously recirculating electrostatic chamber with a custom pump measures ${}^{222}$Rn emanation down to about 20 µBq in four-week runs — a sensitivity it calls world-leading for material assay.

desk verdict A useful, incremental instrumentation paper with new emanation data and a real analysis framework, but the absolute rates depend on an unverified transfer of static calibration to recirculating flow. read the letter →

arxiv 2504.15464 v3 pith:G4WME7ZY submitted 2025-04-21 physics.ins-det hep-ex

nEXO Collaboration: A. Anker , P. A. Breur , B. Mong , P. Acharya , A. Amy , E. Angelico , I. J. Arnquist , A. Atencio
show 132 more authors
J. Bane V. Belov E. P. Bernard T. Bhatta A. Bolotnikov J. Breslin J. P. Brodsky S. Bron E. Brown T. Brunner B. Burnell E. Caden L. Q. Cao G. F. Cao D. Cesmecioglu D. Chernyak M. Chiu R. Collister T. Daniels L. Darroch R. DeVoe M. L. di Vacri Y. Y. Ding M. J. Dolinski A. Dragone B. Eckert M. Elbeltagi A. Emara W. Fairbank N. Fatemighomi B. Foust Y. S. Fu D. Gallacher N. Gallice G. Giacomini W. Gillis A. Gorham R. Gornea G. Gratta Y. D. Guan C. A. Hardy S. Hedges M. Heffner E. Hein J. D. Holt A. Iverson X. S. Jiang A. Karelin D. Keblbeck I. Kotov A. Kuchenkov K. S. Kumar A. Larson M. B. Latif K. G. Leach B. G. Lenardo A. Lennarz D. S. Leonard K. Leung H. Lewis G. Li X. Li Z. Li C. Licciardi R. Lindsay R. MacLellan S. Majidi C. Malbrunot M. Marquis J. Masbou M. Medina-Peregrina S. Mngonyama D. C. Moore X. E. Ngwadla K. Ni A. Nolan S. C. Nowicki J. C. Nzobadila Ondze A. Odian J. L. Orrell G. S. Ortega C. T. Overman L. Pagani H. Peltz Smalley A. Perna A. Piepke A. Pocar V. Radeka E. Raguzin R. Rai H. Rasiwala D. Ray S. Rescia F. Retiére G. Richardson N. Rocco R. Ross P. C. Rowson R. Saldanha S. Sangiorgio S. Sekula T. Shetty L. Si F. Spadoni V. Stekhanov X. L. Sun S. Thibado T. Totev S. Triambak R. H. M. Tsang O. A. Tyuka E. van Bruggen M. Vidal S. Viel M. Walent H. Wang Q. D. Wang Y. G. Wang M. Watts M. Wehrfritz W. Wei L. J. Wen U. Wichoski S. Wilde M. Worcester X. M. Wu H. Xu H. B. Yang L. Yang M. Yu O. Zeldovich J. Zhao
This is my paper · ORCID
classification physics.ins-dethep-ex
keywords radonemanationelectrostaticchamberradon-222assayrecirculatinggaslooplow-backgroundmaterialscreeningalphaspectroscopyBatemanequationfittingneutrinolessdoublebetadecaybackground
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

The paper claims that a radon assay instrument which keeps the sample in a closed, continuously recirculating gas loop with an electrostatic chamber can measure ${}^{222}$Rn emanation rates down to about 20 µBq at 68% confidence in four-week runs, and that this sensitivity is, to its knowledge, world-leading for material assay. The continuous design removes the transfer step of traditional injection assays: a custom bellows pump sweeps radon from the sample chamber into the detector as fast as the sample emits it, so the measured rate becomes proportional to the emanation rate and sensitivity grows with counting time. A commercial ${}^{226}$Ra source of certified activity fixes the absolute detection efficiency, a dedicated background run is subtracted, and a volume-sharing factor accounts for decays that occur outside the detector volume; the analysis framework PyDAn fits the decay-chain time structure to extract each sample's emanation rate. This floor matters because future liquid-xenon detectors searching for neutrinoless double $\beta$ decay and dark matter need to hold ${}^{222}$Rn below roughly 0.1–0.25 µBq per kilogram, which forces builders to screen every wetted material at exactly this level of sensitivity.

What carries the argument

The load-bearing object is the closed recirculation loop: a sample emanation chamber, an electrostatic chamber (a grounded steel vessel holding a silicon photodiode biased at $-1000$ V, which attracts the positive ions produced when ${}^{222}$Rn decays), and a custom bellows pump that cycles carrier gas at 0.1–0.2 SLM so radon is carried to the detector in less than a second. The loop's defining feature is that emanation and detection happen simultaneously, so the observed count rate approaches the emanation rate after a few hours of stabilization. The quantitative machinery is PyDAn, the paper's analysis framework: it solves the Bateman decay-chain equations as a matrix exponential $N(t) = V e^{\Lambda t} V^{-1} N_0$, fits the energy- and time-binned $\alpha$ counts by minimizing the negative log-likelihood, and extracts the initial ${}^{226}$Ra population that supports ${}^{222}$Rn emanation. Absolute scale comes from a static calibration performed with the loop isolated, in which a known ${}^{222}$Rn population is built up in a commercial ${}^{226}$Ra source, injected into the evacuated ESC, and compared with the fit's initial ${}^{222}$Rn population; that efficiency is then applied to flowing sample runs along with a per-run volume-sharing factor, while the ratio of ${}^{218}$Po to ${}^{214}$Po counts, $\varepsilon_{84}$, is the diagnostic that flags runs where ion collection has degraded (below about 0.7 the assay is re-measured).

What would settle it

Run the efficiency calibration with the loop flowing: either inject a known ${}^{222}$Rn population into the full closed loop, or place a certified, continuously emanating ${}^{226}$Ra source in the sample chamber position, and compare the detection efficiency extracted from that run with the static-calibration value. If the flow-mode efficiency differs from the static value by more than the quoted ~4% combined calibration uncertainty, every absolute emanation rate in the results table is off by that ratio; an independent cross-check would be to assay one of the same samples, for instance the 290 µBq ceramic beads, with an injection-type detector such as a Lucas cell and compare the two results.

Watch

Extended reading notes

Core claim

On the paper's own terms, the result is that recirculating radon assay does not cost sensitivity: continuous transport combined with time-resolved Bateman fitting reaches a statistically limited minimal detectable activity of about 20 µBq at 68% confidence after roughly four weeks, which the authors state is, to their knowledge, the best sensitivity yet reported for material assay. In this configuration, ${}^{222}$Rn emitted by a sample is carried by argon or nitrogen into the electrostatic chamber, where the positive daughter ions ${}^{218}$Po and ${}^{214}$Po are electrostatically drifted onto a silicon photodiode and identified by their $\alpha$ energies, and the fit extracts the ${}^{226}$Ra-supported emanation rate. Converting that fit into an absolute rate requires three corrections: division by the measured detection efficiency (0.35–0.45), division by the ESC's volume share of the loop, and subtraction of a dedicated background measurement; the nine background configurations average 197 µBq. The technique separates the sample signal from the instrument background by time structure — radon from the sample builds to steady state while the background stays flat — which is what lets long runs push the measurement floor to about 20 µBq, as demonstrated by the reported emanation results for springs, getters, purifiers, cables, ceramic beads, and zirconium pellets.

Load-bearing premise

Every absolute emanation rate in the results table inherits a single detection efficiency that is measured with the pump off — a known amount of ${}^{222}$Rn is injected into the evacuated, static detector — but is then applied to sample runs taken with the recirculation pump flowing, and the paper reports no efficiency measurement under flow, so any flow-induced change in ion collection or plate-out would scale all quoted rates by an unknown factor.

Editorial extensions

If this is right

  • Materials for next-generation liquid-xenon detectors can be screened at the ~20 µBq level, matching the sensitivity previously available only from batch injection systems while avoiding the radon lost when samples are transferred.
  • The emanation signal builds to steady state while the background stays flat, so longer runs and lower instrument backgrounds both push the measurable floor down; the paper identifies a cleaner room and internal surface passivation or etching as the next steps to shrink the ~200 µBq background.
  • Because transport to the detector takes under a second, the same loop is in principle sensitive to the short-lived isotopes ${}^{220}$Rn and ${}^{219}$Rn as well as ${}^{222}$Rn, though the ${}^{220}$Rn efficiency calibration is left for future work.
  • The assay results are directly usable design data: the SAES PS4-MT3 purifier stays below 70 µBq even with its heaters at 550 °C, whereas 357 g of GetterMax 133 beads emanate about 1.84 mBq — a clear material-selection signal for low-background construction.
  • The paper identifies the custom bellows pump as the practical weak point — its bellows is guaranteed for only about three million strokes, roughly two months of continuous operation, and can fail by leaking air in — so a magnetically coupled piston pump is being developed for future instruments.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The decisive check the paper leaves implicit is an efficiency measurement under recirculating flow: a sealed certified source placed in the sample chamber would test the static-to-flow extrapolation in a single run.
  • The scalar volume-sharing factor becomes a progressively weaker correction as sample chambers grow, because radon decaying outside the ESC is simply invisible; screening very large components will eventually need a transport-aware model that tracks where each decay occurs in the loop.
  • The same hardware is a ready-made online radon monitor: a calibrated loop attached to a live gas system could report ${}^{222}$Rn continuously during detector operation, not only during material screening.
  • PyDAn's waveform-level fitting of the correlated ${}^{214}$Bi–${}^{214}$Po pair events, which recovers about 88% of pairs inside the capture window, is a transferable technique that should improve energy resolution and pileup rejection in other alpha-counting instruments.
Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

1 major / 5 minor

Summary. This manuscript describes the development of an ultra-sensitive radon assay instrument in which an electrostatic chamber (ESC) is connected to a sample emanation chamber in a closed recirculating gas loop. The authors present a custom recirculation pump, a Python-based analysis framework (PyDAn) that fits time-binned alpha spectra to Bateman-chain solutions, and an absolute calibration using a commercial 226Ra Pylon source. Background measurements are repeated in nine configurations, and emanation rates are reported for several samples. The central claim is that this system can measure 222Rn emanation rates with statistical uncertainties around 20 microbecquerels over roughly four-week runs, which the authors state is world leading for material assay.

Significance. If the absolute calibration transfer is valid, this instrument directly addresses the material-screening needs of next-generation low-background experiments such as nEXO and XLZD. The paper makes the DAQ electronics and analysis framework publicly available, provides a reproducible fitting procedure with decay data from ENSDF, and gives a detailed systematic accounting (calibration, volume sharing, background). The reported reproducibility of the efficiency (<2%) and the repeated, dedicated background measurements are strengths. The principal open question is whether the detection efficiency measured in a static injection configuration remains valid when the sample assay is performed with the pump running in a closed loop.

major comments (1)
  1. [Sec. 4.1 and Sec. 4.3] The detection efficiency is calibrated in a static configuration in which a known 222Rn population is injected into the evacuated ESC vessel with no recirculation loop, while all sample assays are conducted with the recirculation pump running in a closed loop. The same efficiency is then applied to the assay data, corrected only by a volume-sharing factor. The paper does not report any measurement that bounds a possible flow-induced change in the ion collection efficiency (fz) inside the ESC. If recirculation changes fz by a common factor, every absolute emanation rate in Table 1 and the claimed 20 µBq minimum detectable activity scale by that factor; the ϵ84 diagnostic cannot reveal this because a common-mode reduction leaves the 218Po/214Po ratio unchanged. A validation measurement with a known 222Rn source in the recirculating loop (with the pump on) is required to support the absolute calibration.
minor comments (5)
  1. [Sec. 3.3, Eq. (3)] Equation (3) contains a typographical error in the subscript 'Mi. j'; this should be 'M_{i,j}'.
  2. [Secs. 3.1 and 3.2] The framework name is written inconsistently as both 'PyDAn' and 'PyDAN'; please choose one spelling.
  3. [Sec. 4.3] The phrase 'measurement uncertainties of ~20 µBq' refers to the individual sample or background measurements, not the background-subtracted emanation; for the Beryllium Copper springs the final emanation uncertainty is 29 µBq. Please clarify to avoid overstating the achieved sensitivity.
  4. [Conclusion] The 'world leading' claim would be more convincing with a quantitative comparison to other state-of-the-art emanation assay systems, such as the XENON1T measurements cited as Ref. [20].
  5. [Fig. 2] The minimum detectable activity curve is adapted from prior work without stating the MDA definition or the statistical procedure (e.g., Currie or Feldman-Cousins); please specify the definition used.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity found; emanation rates are derived from external Pylon-source calibration, Bateman-equation fits to count data, background subtraction, and independently estimated volume-sharing, with no equation reducing the result to its own inputs.

full rationale

The paper's central result—absolute 222Rn emanation rates and the 20 µBq sensitivity claim—is obtained by fitting 214Po and 218Po count time series to Bateman-equation solutions (Sec. 3.3, Eqs. 1–4), with the overall ESC detection efficiency measured absolutely against a 62 Bq Pylon 226Ra source (Sec. 4.1, Eq. 5). The injected 222Rn activity in the calibration is computed from the known source activity and decay equations, and the fitted 222Rn population is divided by that injected population to obtain efficiency; this is a standard external calibration, not a fit of the target quantity. Sample emanation rates are then background-subtracted (Sec. 4.2) and corrected by the ESC-to-total-volume ratio, an independently estimated geometric factor. The MDA curve in Fig. 2 is a calculated estimate based on assumed efficiency and background rates, explicitly labeled as modified from Refs. [21, 23], and is not a fit target or an output that is defined in terms of the final assay results. The possibility that the static calibration efficiency does not transfer perfectly to recirculating sample assays is a systematic-uncertainty or correctness concern, not circularity: no equation in the paper defines the emanation rate through that same emanation rate, and no fitted parameter is renamed as a prediction. The self-citations present, such as nEXO design documents [4, 11] used for motivation targets and Ref. [38] used for the 90% CL convention in Table 1, are not load-bearing for the derivation. The acknowledged gap that 220Rn progeny efficiency is not yet determined is a scope limitation, not a circular step. The derivation chain is self-contained against external benchmarks, so the circularity score is 0.

Assumptions & free parameters 3 free parameters · 6 assumptions · 0 invented entities

The central result rests on standard decay-chain mathematics and externally calibrated efficiency. The two sensitive assumptions are the static-to-recirculating efficiency transfer and background stability per configuration; both are measured or stated but not independently proven. No invented physical entities are introduced.

free parameters (3)
  • ESC detection efficiency epsilon = 0.35 to 0.45, per carrier gas and ESC
    Measured by injecting a known 222Rn population from a 62 Bq Pylon 226Ra source (Sec. 4.1). It converts 214Po counts to activity, and all absolute emanation rates scale with it.
  • Volume-sharing factor V_ESC/V_total = e.g., 0.92 for an empty DN63 CF nipple; estimated per run
    Used in Sec. 4.1 to 4.3 to correct for decays in plumbing outside the ESC. It is estimated rather than directly measured and matters most for inline samples.
  • Initial populations N_Ra, N_Rn, N_Th and collection ratios epsilon_84, epsilon_62 = Not tabulated in the paper
    Free parameters in the PyDAn Bateman fit (Sec. 3.3). The fitted 226Ra population is the source of the reported emanation rate, while the ratios are diagnostics for ion collection.
assumptions (6)
  • standard math Bateman and matrix-exponential decay equations describe progeny populations.
    Invoked in Sec. 3.3 with Eq. 1 and Eq. 2; this is a standard radioactive decay model.
  • standard math ENSDF half-lives and alpha energies are correct.
    PyDAn hard-codes ENSDF values in Sec. 3.3 (Ref. [15]); this is accepted external nuclear data.
  • domain assumption The 232Th chain is in equilibrium up to 224Ra.
    PyDAn's model assumes this in Sec. 3.3; if false, 220Rn-chain contributions could bias the fits.
  • domain assumption Static calibration efficiency applies during recirculating flow.
    Efficiency is measured without the loop (Sec. 4.1) and used with a volume-sharing factor on loop measurements (Sec. 4.3); no direct flow-efficiency check is reported.
  • domain assumption Background without the sample equals background during the sample run.
    Sec. 4.2 uses a dedicated empty-chamber or bypass background per sample; nine configurations varied with a standard deviation of 23 microbecquerels, so this is approximate.
  • domain assumption Initial radon progeny populations are zero at the start of runs.
    Sec. 3.3 sets progeny initial populations to zero or masks the first hours; for multi-week assays this is reasonable but not verified for every run.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Ultra-sensitive radon assay using an electrostatic chamber in a recirculating system." pith.science (2026). https://pith.science/paper/G4WME7ZY

@misc{pith2026250415464,
  author       = {Pith},
  title        = {Pith review of: Ultra-sensitive radon assay using an electrostatic chamber in a recirculating system},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/G4WME7ZY}},
  note         = {Machine review of arXiv:2504.15464}
}
abstract

Rare event searches such as neutrinoless double beta decay and Weakly Interacting Massive Particle detection require ultra-low background detectors. Radon contamination is a significant challenge for these experiments, which employ highly sensitive radon assay techniques to identify and select low-emission materials. This work presents the development of ultra-sensitive electrostatic chamber (ESC) instruments designed to measure radon emanation in a recirculating gas loop, for future lower background experiments. Unlike traditional methods that separate emanation and detection steps, this system allows continuous radon transport and detection. This is made possible with a custom-built recirculation pump. A Python-based analysis framework, PyDAn, was developed to process and fit time-dependent radon decay data. Radon emanation rates are given for various materials measured with this instrument. A radon source of known activity provides an absolute calibration, enabling statistically-limited minimal detectable activities of 20 $\mu$Bq. These devices are powerful tools for screening materials in the development of low-background particle physics experiments.

Figures

Figures reproduced from arXiv: 2504.15464 by the authors.

Figure 1
Figure 1. Condensed diagram of the 238U decay series. The half-lives and branching ratios for isotopes of interest are given as well as the alpha energy values [15]. 1.2. Radon Assay Overview Different approaches to performing radon assay exist, which fall into two broad categories based on their measurement process. The first type, which we refer to as injection systems, separate the emanation and measurement process into tw… view at source ↗
Figure 2
Figure 2. The minimum detectable activity of the recirculation instrument with 68% confidence level. Assumptions are that 40% of all [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Simplified diagram of the radon assay system. A pump recirculates the carrier gas, transporting radon from the emanation [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗
Figures from the paper (6 more)
Figure 4
Figure 4. Figure 4: Cross section of the bellows pump CAD. Highlighted are the reed valves (red), displacer plug bottom (cyan), and inverting [PITH_FULL_IMAGE:figures/full_fig_p006_4.png]
Figure 5
Figure 5. Figure 5: Examples of three different emanation vessels: A) DN63 CF nipple with Zr pellets, B) SAES rare gas purifier with VCR fittings, and C) 50 ft long copper tube with brazed VCR fittings for a HV cable. fα. Similarly for β-decays, the daughter ion fraction is denoted by fβ.…
Figure 6
Figure 6. Figure 6: Diagram of 222Rn collection probabilities inside the ESC. The value fα (fβ) represents the positive ion fraction of an atom undergoing α (β) decay while fz represents the ion collection efficiency on the photodiode. 8 [PITH_FULL_IMAGE:figures/full_fig_p008_6.png]
Figure 7
Figure 7. Figure 7: Waveform from a 214Bi - 214Po signal (blue) and the fit to the waveform (orange). Each signal peak is fit as a decaying exponential with decay constant τ, baseline B, and amplitudes Eα and Eβ. The second signal is assumed to be the 214Po α at t = 0 (trigger), and the f…
Figure 8
Figure 8. Figure 8: Histogram of a complex energy spectrum containing [PITH_FULL_IMAGE:figures/full_fig_p010_8.png]
Figure 9
Figure 9. Figure 9: 214Po and 218Po count-rates versus time for an assay of ceramic beads (top, also see [PITH_FULL_IMAGE:figures/full_fig_p011_9.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

37 extracted references · 20 canonical work pages

  1. [1]

    EXO-200 Collaboration, Search for Neutrinoless Double-Beta Decay in 136Xe with EXO-200, Physical Review Letters 109 (3) (Jul. 2012). doi:10.1103/physrevlett.109.032505

    doi:10.1103/physrevlett.109.032505 2012

  2. [2]

    LZ Collaboration, The LUX-ZEPLIN (LZ) experiment, Nucl. Instr. and Meth. in Phys. Res. A 953 (2020) 163047.doi:10.1016/ j.nima.2019.163047

    arXiv 2020

  3. [3]

    XENON Collaboration, The XENONnT dark matter experiment, The European Physical Journal C 84 (8) (Aug. 2024). doi: 10.1140/epjc/s10052-024-12982-5

    doi:10.1140/epjc/s10052-024-12982-5 2024

  4. [4]

    doi:10.48550/ARXIV.1805.11142

    nEXO Collaboration, nEXO Pre-Conceptual Design Report, arxiv [physics.ins-det] (2018). doi:10.48550/ARXIV.1805.11142

    arXiv doi:10.48550/arxiv.1805.11142 2018

  5. [5]

    Aalbers, et al., A next-generation liquid xenon observatory for dark matter and neutrino physics, Journal of Physics G: Nuclear and Particle Physics 50 (1) (2022) 013001

    J. Aalbers, et al., A next-generation liquid xenon observatory for dark matter and neutrino physics, Journal of Physics G: Nuclear and Particle Physics 50 (1) (2022) 013001. doi:10.1088/1361-6471/ac841a

    doi:10.1088/1361-6471/ac841a 2022

  6. [7]

    Aprile, et al., Radon Removal in XENONnT down to the Solar Neutrino Level, arXiv (2025)

    E. Aprile, et al., Radon Removal in XENONnT down to the Solar Neutrino Level, arXiv (2025). doi:10.48550/ARXIV.2502. 04209

    doi:10.48550/arxiv.2502 2025

  7. [8]

    Aalbers, et al., Background determination for the LUX-ZEPLIN dark matter experiment, Physical Review D 108 (1) (Jul

    J. Aalbers, et al., Background determination for the LUX-ZEPLIN dark matter experiment, Physical Review D 108 (1) (Jul. 2023). doi:10.1103/physrevd.108.012010

    work page doi:10.1103/physrevd.108.012010 2023

  8. [9]

    EXO-200 Collaboration, Investigation of radioactivity-induced backgrounds in EXO-200, Physical Review C 92 (1) (Jul. 2015). doi:10.1103/physrevc.92.015503

    work page doi:10.1103/physrevc.92.015503 2015

Show all 37 references
  1. [10]

    doi:10.48550/ARXIV.2410.17137

    XLZD Collaboration, The XLZD Design Book: Towards the Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics, arXiv [hep-ex] (2024). doi:10.48550/ARXIV.2410.17137

    2024 doi

  2. [11]

    doi:10.1088/1361-6471/ac3631

    nEXO Collaboration, nEXO: neutrinoless double beta decay search beyond 10 28 year half-life sensitivity, Journal of Physics G: Nuclear and Particle Physics 49 (1) (2021) 015104. doi:10.1088/1361-6471/ac3631

    2021 doi

  3. [12]

    PandaX Collaboration, PandaX-xT—A deep underground multi-ten-tonne liquid xenon observatory, Science China Physics, Me- chanics & Astronomy 68 (2) (Nov. 2024). doi:10.1007/s11433-024-2539-y

    2024 doi

  4. [13]

    D. S. Akerib, et al., The LUX-ZEPLIN (LZ) radioactivity and cleanliness control programs, The European Physical Journal C 80 (11) (Nov. 2020). doi:10.1140/epjc/s10052-020-8420-x

    2020 doi

  5. [14]

    Redshaw, et al., Mass and double-beta-decay q value of 136Xe, Phys

    M. Redshaw, et al., Mass and double-beta-decay q value of 136Xe, Phys. Rev. Lett. 98 (2007). doi:10.1103/PhysRevLett.98. 053003

    2007 doi

  6. [15]

    Version available at http://www.nndc.bnl.gov/ensarchivals/ (accessed 2/19/2025)

    From ENSDF database. Version available at http://www.nndc.bnl.gov/ensarchivals/ (accessed 2/19/2025)

    2025

  7. [16]

    Sazzad, et al., Radon emanation rate measurements using liquid scintillation counting, Journal of Instrumentation 20 (01) (2025) P01020

    A. Sazzad, et al., Radon emanation rate measurements using liquid scintillation counting, Journal of Instrumentation 20 (01) (2025) P01020. doi:10.1088/1748-0221/20/01/p01020

    2025 doi

  8. [17]

    M. Liu, H. Lee, A. McDonald, 222Rn emanation into vacuum, Nucl. Instr. and Meth. in Phys. Res. A 329 (1–2) (1993) 291–298. doi:10.1016/0168-9002(93)90948-h

    1993 doi

  9. [18]

    Blevis, et al., Measurement of dissolved in water at the Sudbury Neutrino Observatory, Nucl

    I. Blevis, et al., Measurement of dissolved in water at the Sudbury Neutrino Observatory, Nucl. Instr. and Meth. in Phys. Res. A 517 (1–3) (2004) 139–153. doi:10.1016/j.nima.2003.10.103

    2004 doi

  10. [19]

    Zuzel, H

    G. Zuzel, H. Simgen, High sensitivity radon emanation measurements, Applied Radiation and Isotopes 67 (5) (2009) 889–893. doi:10.1016/j.apradiso.2009.01.052

    2009 doi

  11. [20]

    XENON Collaboration, 222Rn emanation measurements for the XENON1T experiment, The European Physical Journal C 81 (4) (Apr. 2021). doi:10.1140/epjc/s10052-020-08777-z

    2021 doi

  12. [21]

    S. A. Br ¨unner, Mitigation of 222Rn induced background in the XENON1T dark matter experiment, Ph.D. thesis, Heidelberg University (2017). doi:10.11588/HEIDOK.00023261

    2017 doi

  13. [22]

    J. E. Armstrong, et al., Radon burden and Xe purification performance of hot zirconium getters, in: LOW RADIOACTIVITY TECHNIQUES 2022: Proceedings of the 8th International Workshop on LRT, V ol. 2908, AIP Publishing, 2023, p. 070002. doi:10.1063/5.0161727

    2022 doi

  14. [23]

    Mamedov, I

    F. Mamedov, I. ˇStekl, J. Kon´ıˇcek, K. Smolek, P. ˇCerm´ak, Development of an ultra-sensitive radon detector for the SuperNEMO experiment, Journal of Instrumentation 6 (12) (2011) C12008–C12008. doi:10.1088/1748-0221/6/12/c12008

    2011 doi

  15. [24]

    J.-X. Wang, T. C. Andersen, J. J. Simpson, An electrostatic radon detector designed for water radioactivity measurements, Nucl. Instr. and Meth. in Phys. Res. A 421 (3) (1999) 601–609. doi:10.1016/s0168-9002(98)01230-3

    1999 doi

  16. [25]

    SNO Collaboration, Measurement of radium concentration in water with Mn-coated beads at the Sudbury Neutrino Observatory, Nucl. Instr. and Meth. in Phys. Res. A 501 (2–3) (2003) 399–417. doi:10.1016/s0168-9002(03)00616-8

    2003 doi

  17. [26]

    Farine, Assay of Radon and Radium in Water: Techniques Developed at SNO, in: AIP Conference Proceedings, V ol

    J. Farine, Assay of Radon and Radium in Water: Techniques Developed at SNO, in: AIP Conference Proceedings, V ol. 785, AIP, 2005, p. 199–208. doi:10.1063/1.2060472

    2005 doi

  18. [27]

    R. W. Schnee, et al., Removal of long-lived 222rn daughters by electropolishing thin layers of stainless steel, arXiv (2014). doi: 10.48550/ARXIV.1404.5843

    2014 doi arXiv

  19. [28]

    LePort, et al., A magnetically driven piston pump for ultra-clean applications, Review of Scientific Instruments 82 (10) (Oct

    F. LePort, et al., A magnetically driven piston pump for ultra-clean applications, Review of Scientific Instruments 82 (10) (Oct. 2011). doi:10.1063/1.3653391

    2011 doi

  20. [29]

    Brown, et al., Magnetically-coupled piston pump for high-purity gas applications, The European Physical Journal C 78 (7) (Jul

    E. Brown, et al., Magnetically-coupled piston pump for high-purity gas applications, The European Physical Journal C 78 (7) (Jul. 2018). doi:10.1140/epjc/s10052-018-6062-z

    2018 doi

  21. [30]

    P. K. Hopke, The initial behavior of 218Po in indoor air, Environment International 15 (1) (1989) 299–308. doi:10.1016/ 0160-4120(89)90042-1

    1989

  22. [31]

    Pagelkopf, J

    P. Pagelkopf, J. Porstend ¨orfer, Neutralisation rate and the fraction of the positive 218Po-clusters in air, Atmospheric Environment 37 (8) (2003). doi:10.1016/S1352-2310(02)00997-4 . 14

    2003 doi

  23. [32]

    doi:10.1103/physrevc.92.045504

    EXO-200 Collaboration, Measurements of the ion fraction and mobility of α− and β−decay products in liquid xenon using the EXO-200 detector, Physical Review C 92 (4) (10 2015). doi:10.1103/physrevc.92.045504

    2015 doi

  24. [33]

    Mong, ESC Electronics, https://github.com/bungernut/ESC_Electronics (2024)

    B. Mong, ESC Electronics, https://github.com/bungernut/ESC_Electronics (2024)

    2024

  25. [34]

    Bateman, The solution of a system of di fferential equations occurring in the theory of radioactive transformations, in: Proc

    H. Bateman, The solution of a system of di fferential equations occurring in the theory of radioactive transformations, in: Proc. Cambridge Philos. Soc., V ol. 15, 1910, pp. 423–427

    1910

  26. [35]

    C. R. Harris, et al., Array programming with NumPy, Nature 585 (7825) (2020) 357–362. doi:10.1038/s41586-020-2649-2

    2020 doi

  27. [36]

    Levy, A matrix exponential approach to radioactive decay equations, American Journal of Physics 86 (12) (2018) 909–913

    E. Levy, A matrix exponential approach to radioactive decay equations, American Journal of Physics 86 (12) (2018) 909–913. doi:10.1119/1.5064446

    2018 doi

  28. [37]

    Pylon Electronics Inc https://pylonelectronics-radon.com/radioactive-sources/ (2015)

    2015

  29. [38]

    Tsang, et al., An integrated online radioassay data storage and analytics tool for nEXO, Nucl

    R. Tsang, et al., An integrated online radioassay data storage and analytics tool for nEXO, Nucl. Instr. and Meth. in Phys. Res. A 1055 (2023) 168477. doi:10.1016/j.nima.2023.168477. 15

    2023

Pith tools

Reviewed August 16, 2026 · model on record in the stance chip above.