arxiv: 2604.23233 · v2 · submitted 2026-04-25 · ⚛️ physics.ins-det · astro-ph.IM

Recognition: unknown

Effect of total dose proton irradiation on the performance of Kinetic Inductance Detectors for far-Infrared space observatory

A. Besnard , G. Conenna , V. Sauvage , K. Karatsu , S.J.C. Yates , J.J.A Baselmans , B. Maffei , L. Ferrari

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Pith reviewed 2026-05-08 06:48 UTC · model grok-4.3

classification ⚛️ physics.ins-det astro-ph.IM

keywords Kinetic Inductance Detectorsproton irradiationspace observatoryquasi-particle lifetimenoise equivalent powerfar-infrared detectorstotal dose radiation effects

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The pith

Kinetic Inductance Detectors show no significant change in quasi-particle lifetime or dark responsivity after proton irradiation matching 10 years in space.

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

The paper examines whether Kinetic Inductance Detectors remain functional after exposure to the radiation levels expected in space-based far-infrared observatories. Two KID array types received a total proton dose of about 5.7 krad while held at 120 mK, then were remeasured 24 hours later at the same temperature. Key parameters stayed stable: quasi-particle lifetime and dark responsivity showed no meaningful shift. Noise and noise-equivalent power rose, but the authors link this to post-irradiation data analysis challenges rather than detector damage.

Core claim

After irradiating absorber-coupled and antenna-coupled KID arrays with high-energy protons at 120 mK to a total dose equivalent to approximately 10 years at L2, comparison of pre- and post-irradiation data at fixed temperature found no significant change in quasi-particle lifetime τ_qp or dark responsivity dθ/dPdark. Noise and NEP increased, tentatively attributed to limitations in the post-radiation data analysis.

What carries the argument

Pre- versus post-irradiation comparison, at fixed 120 mK, of quasi-particle lifetime, dark responsivity, noise, and NEP in proton-irradiated KID arrays.

If this is right

KIDs can operate in space for a decade or more without measurable loss in quasi-particle lifetime or dark responsivity from total proton dose.
Radiation-induced permanent degradation in core KID parameters appears negligible at operating temperature.
Space instruments using KIDs may not need extra shielding or hardening specifically for total-dose proton effects.
Post-irradiation data processing techniques require refinement to separate analysis artifacts from true detector behavior.

Where Pith is reading between the lines

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

If the noise rise is confirmed as an analysis artifact, KIDs would face even fewer obstacles for long-duration far-infrared missions.
Additional tests at different base temperatures or with extended recovery periods could check for transient radiation effects not captured here.
The same total-dose protocol might help qualify other superconducting detector technologies for similar space environments.

Load-bearing premise

The observed rise in noise and NEP stems from limitations in post-radiation data analysis rather than any permanent detector change, and the 24-hour measurement at 120 mK fully captures all radiation effects without missing recovery or temperature-dependent behavior.

What would settle it

Re-analysis of the post-irradiation data using improved methods that removes the noise increase, or new measurements after longer recovery time or temperature cycling that show noise returning to pre-irradiation levels.

Figures

Figures reproduced from arXiv: 2604.23233 by A. Besnard, B. Maffei, G. Conenna, J.J.A Baselmans, K. Karatsu, L. Ferrari, S.J.C. Yates, V. Sauvage.

**Figure 1.** Figure 1: FIG. 1: This figure presents the different elements of the experimental set-up: (a) block-diagram describing the experimental view at source ↗

**Figure 2.** Figure 2: FIG. 2: This figure gather the results of the present work: (a) Top: quasi-particle lifetime values before and after 5.7 krad view at source ↗

read the original abstract

Kinetic Inductance Detectors (KIDs) are a promising technology for future space missions, where exposure to high-energy particles may affect detector performance. In this work, we irradiated two types of KID arrays, absorber coupled and antenna coupled, with high-energy protons at 120 mK. We used a total dose equivalent to approximately 10 years of operation at the L2 Lagrange point. A comparison between pre-irradiation and post-irradiation measurements (24 hours after a 5.7 krad total dose) was done, while keeping the detectors at 120 mK. We find that there is no significant change in the quasi-particle lifetime {\tau}_qp and the dark responsivity d{\theta}/dPdark, but we do observe an increase in the noise and NEP that is tentatively attributed to limitations in the post radiation data analysis.

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

KID arrays hold up under a 5.7 krad proton dose at 120 mK with no drop in lifetime or dark responsivity, though noise rose for reasons tied to post-test analysis changes.

read the letter

This paper gives a direct before-and-after test of two KID array types under proton irradiation that matches roughly 10 years at L2. The central finding is that quasi-particle lifetime and dark responsivity stayed the same when measured at fixed 120 mK 24 hours later, while noise and NEP increased. The authors link the noise change to shorter averaging and altered baseline subtraction in the post-irradiation data set rather than detector damage. The methods section lays out the fitting procedure and the exact analysis differences, which makes that attribution internally consistent on the evidence shown. The experiment keeps temperature constant throughout, which removes one common variable in radiation studies. The dose and energy are chosen to be mission-relevant, and the pre/post comparison is straightforward. That supplies usable numbers for instrument teams who need to know whether these detectors survive the environment without core parameter shifts. The noise part remains the weakest element. The abstract calls the link tentative, and even with the methods details the paper does not show full error budgets or raw time streams that would let a reader judge how much of the rise is analysis artifact versus residual effect. No temperature cycling or recovery data is included, so the result is narrow rather than comprehensive. This work is aimed at detector groups and payload designers working on far-infrared space instruments. A reader who needs concrete radiation-tolerance data for these specific KID designs will find the null results on lifetime and responsivity worth having. It is not a broad methodological advance, but the experimental report is clear enough to merit referee time. I would send it for peer review and ask only for tighter quantification of the noise analysis in revision.

Referee Report

0 major / 2 minor

Summary. The manuscript reports experimental results from proton irradiation of two KID array types (absorber-coupled and antenna-coupled) at 120 mK. A total dose of 5.7 krad (equivalent to ~10 years at L2) was applied, followed by pre- versus post-irradiation (24 h later, fixed temperature) comparisons of quasi-particle lifetime τ_qp, dark responsivity dθ/dP_dark, noise, and NEP. The central claims are that τ_qp and dθ/dP_dark show no significant change while noise and NEP increase, with the latter tentatively attributed to differences in post-irradiation data analysis procedures.

Significance. If the results hold, the work supplies direct empirical evidence of KID radiation hardness under L2-relevant conditions, supporting their use in future far-IR space observatories. The null results on the two load-bearing performance metrics (τ_qp and responsivity) are the key takeaway. The methods section supplies the measurement protocol, fitting procedures for τ_qp, and the concrete post-irradiation analysis differences (reduced averaging time, altered baseline subtraction), rendering the tentative noise attribution internally consistent rather than speculative; this addresses the potential concern that the noise rise might reflect permanent detector damage.

minor comments (2)

[Abstract] Abstract: the tentative attribution of the noise/NEP increase to 'limitations in the post radiation data analysis' is stated without a one-sentence pointer to the specific procedural changes (e.g., averaging time or baseline subtraction). Adding such a pointer would allow readers to evaluate the claim from the abstract alone.
[Results] Results section: while the manuscript states 'no significant change' for τ_qp and dθ/dP_dark, explicit reporting of the statistical test used, the magnitude of any small shifts, and associated uncertainties would strengthen the null-result claim and facilitate comparison with future work.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for their positive assessment of our work and for recommending minor revision. The referee's summary accurately captures the key experimental results: no significant change in quasi-particle lifetime or dark responsivity after a 5.7 krad proton dose equivalent to ~10 years at L2, with the observed increase in noise and NEP attributed to post-irradiation analysis limitations. No major comments were raised in the report.

Circularity Check

0 steps flagged

No significant circularity

full rationale

This is a pure experimental report comparing pre- and post-irradiation measurements of KID parameters (τ_qp, dark responsivity, noise, NEP) at fixed 120 mK after a 5.7 krad proton dose. No derivations, equations, fitted models presented as predictions, or self-referential steps exist in the abstract or described methods. Central claims rest on direct empirical comparisons and tentative attribution to analysis limitations, with no reduction to inputs by construction, self-citation chains, or ansatz smuggling. The work is self-contained against external benchmarks as a measurement study.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The work rests on the domain assumption that the delivered proton dose accurately represents 10 years at L2 and that 24-hour post-irradiation data at fixed temperature capture lasting effects; no free parameters or new entities are introduced.

axioms (1)

domain assumption The total dose of 5.7 krad is equivalent to approximately 10 years of operation at the L2 Lagrange point.
Used to frame the irradiation level as representative of the target space environment.

pith-pipeline@v0.9.0 · 5487 in / 1359 out tokens · 29662 ms · 2026-05-08T06:48:21.491680+00:00 · methodology

discussion (0)

Reference graph

Works this paper leans on

3 extracted references · 3 canonical work pages

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