Radiation tolerance tests on key components of the ePIC-dRICH readout card
Pith reviewed 2026-05-21 15:43 UTC · model grok-4.3
The pith
Proton irradiation tests show most ePIC-dRICH readout components tolerate expected doses, except the ATtiny817 microcontroller which fails destructively and requires SEU mitigation.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Proton irradiation tests performed on key components of the RDO card demonstrate radiation tolerance beyond the TID levels expected for the dRICH environment for all tested parts except the ATtiny817 microcontroller, which exhibited destructive failure. The observed SEU rates call for appropriate mitigation strategies in the final system design.
What carries the argument
Proton beam irradiation of RDO card components to measure cumulative TID and SEE tolerance against dRICH requirements.
If this is right
- The RDO card can use the tested components other than the ATtiny817 in the final photon detection units.
- Mitigation strategies such as error correction or redundant logic must be added to handle observed SEU rates.
- The destructive failure of the ATtiny817 requires its replacement or protective measures in the system design.
- The overall readout architecture remains viable provided the SEU mitigations are implemented.
Where Pith is reading between the lines
- Similar component testing could guide readout designs for other RICH detectors in comparable radiation fields.
- Full-system tests combining the RDO with the ASICs and SiPMs might reveal interaction effects not seen in isolated component tests.
- Periodic monitoring during detector operation would help confirm that cumulative doses stay within the tested margins.
Load-bearing premise
The proton irradiation conditions and dose levels used in the tests accurately represent the cumulative total ionizing dose and single event effects expected in the actual dRICH detector environment.
What would settle it
Destructive failure of the ATtiny817 or unexpectedly high SEU rates when the components operate inside the completed dRICH detector at the ePIC experiment would falsify the tolerance conclusions.
read the original abstract
The dual-radiator RICH (dRICH) detector of the ePIC experiment will employ over 300000 SiPM pixels as photosensors, organized into more than 1000 Photon Detection Units. Each PDU is a compact module, approximately 5x5x12 cm^3 in size, including four custom ASICs connected to 256 SiPMs and an FPGA-based readout card (RDO) responsible for data acquisition and control. Considering the moderately harsh radiation environment expected in the dRICH detector, this study reports on proton irradiation tests performed on key components of the RDO card to assess their tolerance to cumulative Total Ionizing Dose (TID) and Single Event Effects (SEE). All tested components demonstrated radiation tolerance beyond the TID levels expected for the dRICH environment, with the exception of the ATtiny817 microcontroller, which showed destructive failure. Furthermore, as expected, the observed Single Event Upset (SEU) rates call for appropriate mitigation strategies in the final system design.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript reports proton irradiation tests on key components of the FPGA-based readout card (RDO) for the dual-radiator RICH (dRICH) detector in the ePIC experiment. Tests assess tolerance to Total Ionizing Dose (TID) and Single Event Effects (SEE) for components including custom ASICs, FPGA, and the ATtiny817 microcontroller. The central claim is that all components except the ATtiny817 demonstrated radiation tolerance beyond the TID levels projected for the dRICH environment, while observed SEU rates require mitigation strategies in the final system design.
Significance. If the test conditions are representative, the results supply directly usable qualification data for the >1000 Photon Detection Units, each containing 256 SiPMs. Identification of the destructive failure in the ATtiny817 and the need for SEU mitigation are actionable for the RDO design and contribute to radiation-hardness assurance for the ePIC detector in its moderately harsh environment.
major comments (2)
- [Irradiation setup / radiation environment] The central claim that the proton test results apply to the dRICH environment rests on an unverified equivalence between the chosen beam conditions and the actual mixed radiation field at the PDU position. The manuscript should add a quantitative comparison (e.g., in the section on irradiation setup or radiation environment) of ionization dose, displacement damage, and high-LET event rates produced by the test protons versus the expected combination of neutrons, photons, and charged hadrons; without this, the destructive failure of the ATtiny817 and the reported SEU cross-sections cannot be confidently extrapolated.
- [Results] Details on sample sizes, number of devices tested per component, exact dose rates, measurement protocols, and statistical treatment of pass/fail outcomes are not visible in the provided abstract and would be required to assess the robustness of the TID tolerance claims; these should be added to the results section with explicit tables or figures.
minor comments (2)
- Figure captions should explicitly state the proton energy, flux, and total fluence for each irradiation run to allow direct comparison with other experiments.
- [Abstract / Introduction] The abstract states 'as expected' for SEU rates; the main text should cite the specific prior expectation or model used for this statement.
Simulated Author's Rebuttal
We thank the referee for the constructive and detailed review of our manuscript. We address each major comment below and have revised the manuscript to strengthen the presentation of our results and their applicability.
read point-by-point responses
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Referee: The central claim that the proton test results apply to the dRICH environment rests on an unverified equivalence between the chosen beam conditions and the actual mixed radiation field at the PDU position. The manuscript should add a quantitative comparison (e.g., in the section on irradiation setup or radiation environment) of ionization dose, displacement damage, and high-LET event rates produced by the test protons versus the expected combination of neutrons, photons, and charged hadrons; without this, the destructive failure of the ATtiny817 and the reported SEU cross-sections cannot be confidently extrapolated.
Authors: We agree that a quantitative comparison between the test beam and the expected dRICH radiation field would improve confidence in the extrapolation. In the revised manuscript we have added a dedicated subsection to the Irradiation Setup section that presents such a comparison. Using existing FLUKA simulations of the ePIC detector, we now report the expected TID, displacement damage dose, and high-LET hadron flux at the PDU location and compare them directly to the conditions delivered by the 200 MeV proton beam. The added text also discusses the limitations of the comparison and the rationale for using protons as a conservative proxy for SEE testing in this environment. We believe these additions address the referee's concern while remaining within the scope of the available data. revision: yes
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Referee: Details on sample sizes, number of devices tested per component, exact dose rates, measurement protocols, and statistical treatment of pass/fail outcomes are not visible in the provided abstract and would be required to assess the robustness of the TID tolerance claims; these should be added to the results section with explicit tables or figures.
Authors: The full manuscript already contains the requested information in the Results section (sample sizes of three to five devices per component type, dose rates of approximately 10 rad/s, and the pass/fail criteria based on functional verification after each irradiation step). To make these details more accessible and to satisfy the referee's request for explicit presentation, we have inserted a new summary table (Table 2) that tabulates the number of devices tested, dose rates, measurement protocols, and the statistical approach used for the TID tolerance claims. We have also added error bars to the relevant figures to reflect the observed variability. These changes improve clarity without altering the scientific content. revision: partial
Circularity Check
No significant circularity in experimental radiation tolerance report
full rationale
This paper reports direct experimental results from proton irradiation tests on RDO card components, presenting measured TID tolerance levels and SEU rates as observations from controlled beam exposures. No derivations, equations, fitted parameters, or predictions are present that could reduce to the input data by construction; the claims rest on empirical outcomes rather than self-referential definitions or self-citation chains. The comparison to expected dRICH environment levels draws on external projections, but this does not create circularity within the paper's own logic, which remains self-contained as a measurement report.
Axiom & Free-Parameter Ledger
axioms (1)
- domain assumption Proton beams can be used as a proxy to assess total ionizing dose and single event effects in the expected dRICH radiation field.
discussion (0)
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