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arxiv: 2604.15406 · v1 · submitted 2026-04-16 · ⚛️ physics.ins-det · nucl-ex

The nEXO Radioassay Program

R. MacLellan , P. Acharya , B. Aharmim , S. Alcantar Anguiano , A. Anker , I. J. Arnquist , D. Auty , T. Bhatta
show 143 more authors
D. Chernyak J. S. Choe B. Cleveland J. Daughhetee A. Der Mesrobian-Kabakian Y. Y. Ding M. L. di Vacri J. Farine A. D. French O. Gileva R. Gornea K. Harouaka K. P. Hobbs E. W. Hoppe L. K. S. Horkley M. Hughes L. Kieser A. Larson I. Lawson E. K. Lee D. S. Leonard K. M. Melby B. Mong O. Nusair D. Pacesila A. Piepke N.D. Rocco R. Saldanha A. B. M. R. Sazzad T. D. Schlieder K. S. Thommasson R. H. M. Tsang V. Veeraraghavan C. Vivo-Vilches J. Vuilleumier L. J. Wen J. Zhao A. Amy A. Atencio J. Bane V. Belov A. Bolotnikov P. A. Breur J. P. Brodsky E. Brown T. Brunner B. Burnell E. Caden G. F. Cao L. Q. Cao D. Cesmecioglu M. Chiu R. Collister E. Coulthard T. Daniels L. Darroch M. J. Dolinski B. Eckert A. Emara N. Fatemighomi W. Fairbank B. Foust D. Gallacher N. Gallice A. Gaur G. Giacomini W. Gillis F. Girard A. Gorham G. Gratta C. A. Hardy M. Heffner E. Hein J. D. Holt A. Iverson A. Karelin D. Keblbeck I. Kotov A. Kuchenkov K. S. Kumar M. B. Latif S. Lavoie B. G. Lenardo K. K. H. Leung H. Lewis X. Li Z. Li C. Licciardi R. Lindsay S. Majidi C. Malbrunot M. Marquis C J. Masbou M. Medina-Peregrina S. Mngonyama D. C. Moore X. E. Ngwadla K. Ni A. Nolan J. C. Nzobadila Ondze A. Odian J. L. Orrell G. S. Ortega C. T. Overman L. Pagani A. Pena-Perez H. Peltz Smalley A. Pocar E. Raguzin R. Rai H. Rasiwala D. Ray A. M. Remnant G. Richardson V. Riot R. Ross P. C. Rowson S. Sangiorgio D.R. Seiner S. Sekula T. Shetty L. Si K. Skarpaas V. Stekhanov X. L. Sun S. Thibado A. Todd T. Totev S. Triambak O. A. Tyuka T. Vallivilayil John E. van Bruggen S. Viel Q. D. Wang M. Watts W. Wei S. Wilde X. M. Wu H. Xu H. B. Yang L. Yang M. Yu O. Zeldovich
This is my paper

Pith reviewed 2026-05-10 09:48 UTC · model grok-4.3

classification ⚛️ physics.ins-det nucl-ex
keywords radioassayradioactivitymaterials screeningdouble beta decaylow backgroundnEXOuraniumthorium
0
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The pith

The nEXO radioassay program provides some of the most restrictive constraints on natural radioactivity in materials.

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

The paper compiles results from radioassays of materials intended for use in the nEXO double-beta decay experiment. These measurements yield upper limits on radioactive contaminants that are among the lowest reported for materials of interest to the low-radioactivity community. The data are intended to help researchers select radiopure materials and avoid redundant testing efforts. Various techniques including gamma spectroscopy and mass spectrometry were used to generate the results.

Core claim

A compilation of radioassay data on numerous materials achieves some of the most restrictive constraints on their natural radioactivity content, supporting the design of the nEXO detector and similar experiments.

What carries the argument

The radioassay program using multiple measurement techniques to quantify trace radioactivity levels in candidate materials.

If this is right

  • Experiments can select materials based on these limits to achieve lower backgrounds.
  • Reduces duplication of radioassay work across the rare-event search community.
  • Supports the sensitivity goals of the nEXO neutrinoless double-beta decay search.
  • Provides a reference for future material screening programs.

Where Pith is reading between the lines

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

  • The results may inform material choices in other fields requiring ultra-low radioactivity, such as quantum sensors.
  • Independent verification of these limits on production materials would strengthen their utility.
  • Extension to additional material types or isotopes could further expand the resource.

Load-bearing premise

The reported assay results accurately represent the radioactivity levels in the materials to be used without systematic biases or contamination.

What would settle it

An independent measurement finding radioactivity levels substantially higher than the upper limits reported here.

Figures

Figures reproduced from arXiv: 2604.15406 by A. Amy, A. Anker, A. Atencio, A. B. M. R. Sazzad, A. Bolotnikov, A. Der Mesrobian-Kabakian, A. D. French, A. Emara, A. Gaur, A. Gorham, A. Iverson, A. Karelin, A. Kuchenkov, A. Larson, A. M. Remnant, A. Nolan, A. Odian, A. Pena-Perez, A. Piepke, A. Pocar, A. Todd, B. Aharmim, B. Burnell, B. Cleveland, B. Eckert, B. Foust, B. G. Lenardo, B. Mong, C. A. Hardy, C J. Masbou, C. Licciardi, C. Malbrunot, C. T. Overman, C. Vivo-Vilches, D. Auty, D. Cesmecioglu, D. Chernyak, D. C. Moore, D. Gallacher, D. Keblbeck, D. Pacesila, D. Ray, D.R. Seiner, D. S. Leonard, E. Brown, E. Caden, E. Coulthard, E. Hein, E. K. Lee, E. Raguzin, E. van Bruggen, E. W. Hoppe, F. Girard, G. F. Cao, G. Giacomini, G. Gratta, G. Richardson, G. S. Ortega, H. B. Yang, H. Lewis, H. Peltz Smalley, H. Rasiwala, H. Xu, I. J. Arnquist, I. Kotov, I. Lawson, J. Bane, J. C. Nzobadila Ondze, J. Daughhetee, J. D. Holt, J. Farine, J. L. Orrell, J. P. Brodsky, J. S. Choe, J. Vuilleumier, J. Zhao, K. Harouaka, K. K. H. Leung, K. M. Melby, K. Ni, K. P. Hobbs, K. Skarpaas, K. S. Kumar, K. S. Thommasson, L. Darroch, L. J. Wen, L. Kieser, L. K. S. Horkley, L. Pagani, L. Q. Cao, L. Si, L. Yang, M. B. Latif, M. Chiu, M. Heffner, M. Hughes, M. J. Dolinski, M. L. di Vacri, M. Marquis, M. Medina-Peregrina, M. Watts, M. Yu, N.D. Rocco, N. Fatemighomi, N. Gallice, O. A. Tyuka, O. Gileva, O. Nusair, O. Zeldovich, P. A. Breur, P. Acharya, P. C. Rowson, Q. D. Wang, R. Collister, R. Gornea, R. H. M. Tsang, R. Lindsay, R. MacLellan, R. Rai, R. Ross, R. Saldanha, S. Alcantar Anguiano, S. Lavoie, S. Majidi, S. Mngonyama, S. Sangiorgio, S. Sekula, S. Thibado, S. Triambak, S. Viel, S. Wilde, T. Bhatta, T. Brunner, T. Daniels, T. D. Schlieder, T. Shetty, T. Totev, T. Vallivilayil John, V. Belov, V. Riot, V. Stekhanov, V. Veeraraghavan, W. Fairbank, W. Gillis, W. Wei, X. E. Ngwadla, X. Li, X. L. Sun, X. M. Wu, Y. Y. Ding, Z. Li.

Figure 1
Figure 1. Figure 1: FIG. 1. Assay results from six HPGe detectors—VdA underground at SNOLAB, GeII and GeIII above ground at UA, GeIV [PITH_FULL_IMAGE:figures/full_fig_p007_1.png] view at source ↗
read the original abstract

Material radioactivity compilations, such as the one presented here, are important enablers of science. They are useful for the selection of radiopure materials used in the design and construction of low-energy rare-event search experiments. They allow researchers developing such experiments to save time on material studies and avoid costly duplication of effort. The data presented here were generated in support of the planned nEXO double-beta decay search. This work contains among the most restrictive constraints on the natural radioactivity content of materials of general interest to the low-radioactivity community, found in any tabulation of this kind. In this study, various techniques were employed; they are described here.

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

0 major / 3 minor

Summary. The manuscript compiles radioassay results obtained via multiple standard techniques (ICP-MS, gamma spectroscopy, and others) for a range of materials under consideration for the nEXO double-beta decay detector. It tabulates upper limits on natural radioactivity (primarily U/Th/K chains) and asserts that these limits are among the most restrictive available in the low-radioactivity literature.

Significance. If the reported limits hold, the compilation provides a practical resource that can reduce redundant assay work for other low-background experiments. The multi-technique data set strengthens the credibility of the constraints for material selection in rare-event searches.

minor comments (3)
  1. [Abstract] The abstract states that 'various techniques were employed' but does not enumerate them or indicate how many materials were assayed; adding a short list would improve immediate clarity for readers.
  2. [Results tables] Tables presenting the final limits should include a column or footnote that explicitly shows the dominant systematic uncertainty for each entry (e.g., calibration, efficiency, or background subtraction) so that the quoted upper bounds can be evaluated without consulting the full methods text.
  3. [Introduction] The manuscript references prior radioassay compilations only in passing; a brief comparison table or paragraph quantifying how many of the new limits improve on the best previous values would strengthen the claim of providing 'among the most restrictive constraints.'

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the positive summary and recommendation of minor revision. No specific major comments were provided in the report, so we have no points to address individually. The manuscript compiles radioassay data supporting nEXO and similar experiments; we stand by the presented limits and multi-technique approach as described.

Circularity Check

0 steps flagged

No significant circularity

full rationale

The paper is a direct experimental compilation of radioassay measurements (ICP-MS, gamma spectroscopy, etc.) reporting upper limits on natural radioactivity in materials for nEXO. It contains no derivations, equations, fitted parameters, predictions, or first-principles results that could reduce to inputs by construction. The central claim of 'among the most restrictive constraints' is a factual statement about the sensitivity of the tabulated data, not a derived quantity. No self-citations function as load-bearing premises, and the work is self-contained against external benchmarks as a data tabulation.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

No free parameters, invented entities, or non-standard axioms; the work rests on standard radioassay methods and decay physics.

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