# 📐  L2 Spec — Photoacoustic-Ultrasound Dual-mode Imaging (PAUS) — Spec Skeleton

**ID:** `L2-509-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-509`](/artifact/l1/L1-509)

> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41553390

---

## 1. Domain Ω

**Type:** `range`

| Parameter | Unit | Range |
|---|---|---|
| H | px | 128 – 512 |
| W | px | 128 – 512 |
| Z | — | 32 – 256 |
| Snr pa db | dB | 5 – 40 |
| Snr us db | dB | 5 – 45 |
| N us modes | — | 1 – 5 |
| Voxel size mm | mm | 0.05 – 1.0 |
| Lambda range nm | nm | [NEEDS_HAND_AUTHORING: bounds] |
| N pa wavelengths | — | 2 – 16 |
| Us bandwidth mhz | MHz | 1 – 20 |
| Speed of sound mps | — | 1400 – 1600 |
| Acoustic attenuation | — | 0.0 – 0.4 |
| Fluence inhomogeneity | — | 0.0 – 0.4 |
| Us center frequency mhz | MHz | 1 – 30 |
| Motion during acquisition | — | 0.0 – 0.3 |
| Acoustic speed heterogeneity | — | 0.0 – 0.1 |
| Pa us synchronization jitter | — | 0.0 – 0.3 |
| Transducer bandwidth difference pa vs us | µs | 0.0 – 0.5 |

## 2. Tolerance (ε)

**Type:** `fn`

```
26.0
```

## 3. Difficulty

| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |

## 4. Fingerprint

`2bc6f7292d48e30e974d476902f89b4c8996b49632f4af5264854c83148bc1d0`

## 5. On-chain Registration

- **Chain hash:** `0x52458478e383ab4907e0668b816e11fa3d1425cad98d00d4ec507d897ef92b0c`
- **Chain tx hash:** `0x75b7e6f7f0bd1a05a7a2aff24ae8f5faa464e950a30b3a7f1d85d0161efe0956`
- **Chain block:** `41553390`

---

## File Mapping

This bundle consists of: `L2-509-001.md`, `L2-509-001.json`.

| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-509-001.md` | Source of truth — edit this | Human or LLM |
| `L2-509-001.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 `L2-509-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._