# 📐 L2 Spec — Quantitative Photoacoustic Tomography (qPAT) — Spec Skeleton
**ID:** `L2-504-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-504`](/artifact/l1/L1-504)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41553376
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| H | px | 128 – 512 |
| W | px | 128 – 512 |
| Z | — | 32 – 256 |
| Snr db | dB | 5.0 – 40.0 |
| N wavelengths | — | 2 – 16 |
| Voxel size mm | mm | 0.05 – 1.0 |
| Lambda range nm | nm | 600 – 1100 |
| Speed of sound mps | — | 1400.0 – 1600.0 |
| Gruneisen uncertainty | — | 0.0 – 0.3 |
| Mu s prime uncertainty | — | 0.0 – 0.3 |
| Transducer bandwidth mhz | MHz | 1.0 – 30.0 |
| Transducer position error | — | 0.0 – 0.2 |
| Background absorption drift | — | 0.0 – 0.2 |
| Light fluence inhomogeneity | — | 0.0 – 0.4 |
| Acoustic speed heterogeneity | — | 0.0 – 0.1 |
## 2. Tolerance (ε)
**Type:** `fn`
```
26.0
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |
## 4. Fingerprint
`a5832a0704e555ab0cef6c3d4a33b48f23fa0bfc38e6c8139321ae0068ee9aed`
## 5. On-chain Registration
- **Chain hash:** `0x67f113d4941b04839f98f5724025f1bfe93760fbf72c79f62c14eaa4b5626bc9`
- **Chain tx hash:** `0x3c142239e294ccafb3e101adaa33a70f9acd779569a82853c2da3e522d68a5be`
- **Chain block:** `41553376`
---
## File Mapping
This bundle consists of: `L2-504-001.md`, `L2-504-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-504-001.md` | Source of truth — edit this | Human or LLM |
| `L2-504-001.json` | Structured metadata for the registry | LLM regenerates from the sections above |
**Prompt for your LLM after editing this Markdown:**
> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.
_This Markdown was auto-synthesized from the catalog row for `L2-504-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._