arxiv: 2604.26386 · v1 · submitted 2026-04-29 · ⚛️ physics.ins-det · hep-ex

Recognition: unknown

Comparison of Silvaco and Synopsys TCAD Predictions Including the Perugia Radiation Damage Model in Silicon Pixel Detectors for the HL-LHC

A. Fondacci, A. Morozzi, D. Passeri, F. Moscatelli, K. Aouadj, M. Bomben, T. Croci

Authors on Pith no claims yet

Pith reviewed 2026-05-07 11:14 UTC · model grok-4.3

classification ⚛️ physics.ins-det hep-ex

keywords silicon pixel detectorsradiation damageTCAD simulationPerugia modelHL-LHCleakage currentdepletion voltagetrap statistics

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The pith

Silvaco and Synopsys TCAD tools produce matching predictions for leakage current, depletion voltage, electric field, and trap statistics in irradiated silicon pixel detectors when both use the Perugia radiation damage model.

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

The paper compares the outputs of Silvaco and Synopsys TCAD device simulations after both incorporate the same set of surface and bulk defects and traps from the Perugia radiation damage model. This comparison covers leakage current, depletion voltage, electric field profiles, and trap occupation at two reference temperatures and fluences expected at the HL-LHC. Agreement between the independent tools indicates that the model implementation is robust across platforms, which matters because these metrics determine the operating voltages and signal loss that will limit tracking performance in the upgraded collider.

Core claim

When the Perugia radiation damage model is included, Silvaco and Synopsys TCAD simulations yield closely consistent results for leakage current, depletion voltage, electric field, and trap statistics in silicon pixel detectors at two distinct reference temperatures and fluences.

What carries the argument

The Perugia radiation damage model, which defines a specific set of surface and bulk defects and traps to represent irradiation effects in the TCAD simulations.

Load-bearing premise

The Perugia radiation damage model accurately represents the surface and bulk defects and traps induced by irradiation in silicon pixel detectors.

What would settle it

Direct experimental measurements of leakage current and depletion voltage in silicon pixel detectors irradiated to the same fluences and measured at the same temperatures, compared against the TCAD predictions from either tool.

read the original abstract

At the High Luminosity Large Hadron Collider (HL-LHC), silicon pixel detectors will be exposed to radiation fluences about 5 to 10 times larger than those experienced by the current innermost pixel layers up to today. Signal loss will be the main limitation to tracking and vertexing performance due to radiation damage in hybrid pixel detectors, with the increase in leakage current and depletion voltage posing severe constraints on operating conditions. It is important to have reliable predictions for all observables - such as charge collection performance, leakage current level and breakdown voltage - after irradiation, in order to estimate operational voltage values and to test the robustness of tracking algorithms. In this paper, the predictions of Silvaco and Synopsys TCAD device simulations are compared when the surface and bulk defects and traps of the ``Perugia radiation damage model'' are included. The results are quite promising regarding leakage current, depletion voltage, electric field and trap statistics, at two distinct reference temperatures and fluences.

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

Silvaco and Synopsys TCAD give similar outputs with the Perugia model, but the paper only compares the two codes and skips any test against measured data from irradiated pixels.

read the letter

The paper runs the Perugia radiation damage model inside both Silvaco and Synopsys TCAD and reports that the two packages line up on leakage current, depletion voltage, electric field, and trap statistics at two fluences and temperatures. That is the entire contribution: a side-by-side check that the same model behaves consistently across two commercial simulators. If you already trust the Perugia parameters and need to pick a tool for HL-LHC pixel work, the agreement might save you some time confirming the codes are interchangeable on these quantities. The implementation details and any quantitative differences are presumably in the full text, which is the only concrete thing the work supplies. The obvious gap is the lack of any experimental anchor. No I-V curves, no C-V data, no charge-collection measurements from real irradiated sensors at the cited fluences appear. The abstract calls the results “quite promising,” yet without numbers, error bars, or a data comparison it is impossible to tell whether the agreement reflects physical accuracy or just shared modeling choices. This leaves the central claim resting on the untested assumption that the Perugia model is already correct. The paper is therefore useful only to the narrow set of TCAD users who want reassurance that the two packages agree when fed the same defect parameters. It does not advance the model, provide new validation, or help decide operating voltages for HL-LHC. I would not send it for peer review; the scope is too limited and the evidence too thin to justify referee time.

Referee Report

2 major / 2 minor

Summary. The manuscript compares Silvaco and Synopsys TCAD device simulations of silicon pixel detectors for HL-LHC conditions, incorporating the Perugia radiation damage model for surface and bulk defects and traps. It examines predictions for leakage current, depletion voltage, electric field, and trap statistics at two reference temperatures and fluences, concluding that the results are promising.

Significance. Consistent predictions across two widely used TCAD platforms when using the same Perugia model would support simulation-based estimates of operating conditions and tracking performance in irradiated hybrid pixel detectors. The work correctly highlights the relevance of leakage current, depletion voltage, and breakdown behavior for HL-LHC operation. However, the significance remains limited because the study performs only a code-to-code comparison without experimental benchmarks.

major comments (2)

Abstract: the statement that results are 'quite promising' for leakage current, depletion voltage, electric field and trap statistics supplies no quantitative metrics (relative differences, agreement percentages, or error bars) between the two codes, preventing assessment of the claimed level of consistency.
Results section: no measured I-V, C-V, or charge-collection data from irradiated pixel sensors at the cited fluences (~10^15–10^16 n_eq/cm²) are shown to benchmark either code's output. Consequently, observed agreement between Silvaco and Synopsys may reflect shared Perugia-model assumptions (trap levels, capture cross-sections, effective doping) rather than physical accuracy, which is load-bearing for the claim that the predictions are promising for HL-LHC detectors.

minor comments (2)

A table listing the Perugia-model parameters (energy levels, cross-sections, introduction rates) as implemented in each TCAD tool would improve reproducibility.
The introduction would benefit from citing recent experimental papers on radiation-induced leakage current and depletion voltage in HL-LHC prototype pixel sensors.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive comments on our manuscript comparing Silvaco and Synopsys TCAD simulations with the Perugia radiation damage model. We will revise the abstract to include quantitative metrics of agreement between the two codes and add clarifying text in the results section to better define the scope of this code-to-code study.

read point-by-point responses

Referee: Abstract: the statement that results are 'quite promising' for leakage current, depletion voltage, electric field and trap statistics supplies no quantitative metrics (relative differences, agreement percentages, or error bars) between the two codes, preventing assessment of the claimed level of consistency.

Authors: We agree that the abstract would benefit from quantitative support. In the revised manuscript we will replace the qualitative phrase with specific metrics drawn from the simulation results, including relative differences in leakage current (typically below 10% across the fluence and temperature range), depletion voltage agreement (within a few volts), and comparable figures for electric-field profiles and trap occupation statistics. These values will be stated explicitly so readers can judge the level of consistency. revision: yes
Referee: Results section: no measured I-V, C-V, or charge-collection data from irradiated pixel sensors at the cited fluences (~10^15–10^16 n_eq/cm²) are shown to benchmark either code's output. Consequently, observed agreement between Silvaco and Synopsys may reflect shared Perugia-model assumptions (trap levels, capture cross-sections, effective doping) rather than physical accuracy, which is load-bearing for the claim that the predictions are promising for HL-LHC detectors.

Authors: The manuscript presents a direct comparison of two TCAD platforms that employ identical Perugia-model parameters; the observed agreement therefore demonstrates consistent numerical implementation rather than independent physical validation. We will add a short paragraph in the results section that states this scope explicitly, notes that the Perugia model has been benchmarked against data in earlier literature, and acknowledges that experimental I-V, C-V or charge-collection comparisons lie outside the present work. This clarification addresses the referee’s concern while preserving the paper’s focus on inter-code consistency for HL-LHC sensor simulations. revision: partial

Circularity Check

0 steps flagged

No circularity: pure code-to-code comparison using pre-existing model

full rationale

The paper reports a side-by-side numerical comparison of Silvaco and Synopsys TCAD outputs when both incorporate the same pre-existing Perugia radiation-damage model. No new derivation, parameter fit, or predictive claim is advanced; the text simply states that the two simulators produce similar results for leakage current, depletion voltage, electric field, and trap statistics at two reference conditions. Because the central activity is verification of numerical agreement rather than any derivation chain, none of the enumerated circularity patterns (self-definition, fitted-input-as-prediction, load-bearing self-citation, etc.) apply. The work is therefore self-contained against external benchmarks and receives the default non-circularity score.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

The central claim rests on the accuracy of the Perugia radiation damage model and the correct implementation of surface and bulk defects in both TCAD packages. No free parameters, axioms, or invented entities are extractable from the abstract.

pith-pipeline@v0.9.0 · 5506 in / 964 out tokens · 61394 ms · 2026-05-07T11:14:19.353422+00:00 · methodology

discussion (0)

Reference graph

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