# 📐 L2 Spec — Scanning Acoustic Microscopy (SAM) Mismatch-Only Spec
**ID:** `L2-120-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-120`](/artifact/l1/L1-120)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41554215
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| H | px | 64 – 2048 |
| W | px | 64 – 2048 |
| Z | — | 16 – 512 |
| F mhz | MHz | 10 – 2000 |
| Snr db | dB | 0.0 – 40.0 |
| Pixel um | µm | 0.5 – 500 |
| Surface curvature | — | 0.0 – 0.3 |
| Multiple reflections | — | 0.0 – 0.3 |
| Water path attenuation | — | 0.0 – 0.2 |
| Coupling fluid variation | — | 0.0 – 0.2 |
## 2. Tolerance (ε)
**Type:** `fn`
```
18.0 + 0.3 * SNR_dB - 8.0 * coupling_fluid_variation - 6.0 * surface_curvature - 6.0 * multiple_reflections
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |
## 4. Fingerprint
`4264537dcb1d9802942200c3a389fe7aa06892d433aa5a4c7e9509b8cdd785a2`
## 5. On-chain Registration
- **Chain hash:** `0x2bd52886684881fcd5d57e6fee1d18066c9d132e4a6a9ea1fb1d8328dcf65c0e`
- **Chain tx hash:** `0xa8a383e516de0f333bf8d38da307fa38220207aec570917d471b16385c6d1619`
- **Chain block:** `41554215`
---
## File Mapping
This bundle consists of: `L2-120-001.md`, `L2-120-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-120-001.md` | Source of truth — edit this | Human or LLM |
| `L2-120-001.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 `L2-120-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._