# 📐 L2 Spec — Scanning TEM (STEM) — HAADF / BF imaging with convergent beam Mismatch-Only Spec
**ID:** `L2-087-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-087`](/artifact/l1/L1-087)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.48 · **Delta tier:** 5
> **⛓ On-chain block:** 41554187
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| H | px | 512 – 8192 |
| W | px | 512 – 8192 |
| Kv | — | 60 – 300 |
| Pixel a | — | 0.1 – 5.0 |
| Beam damage | — | 0.0 – 0.5 |
| Peak electrons | — | 5 – 5000 |
| Scan distortion | — | 0.0 – 0.05 |
| Probe aberration | — | 0.0 – 0.3 |
## 2. Tolerance (ε)
**Type:** `fn`
```
20.0 + 2.0 * log10(peak_electrons / 5) - 15.0 * probe_aberration - 30.0 * scan_distortion
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.48 |
| Delta tier | 5 |
## 4. Fingerprint
`a3daa3e518fb19352daa6775d538017b2d73df5c6f8dfda431ae0896bb6c1951`
## 5. On-chain Registration
- **Chain hash:** `0xc918b0513ac5971a69e51575f25d4e708a64f7332d267c0208152d67a92235cd`
- **Chain tx hash:** `0xd64b5ce2353d15e009ed8fcbe20745feb5a14ec2d72080a2c9afd534d9be45c9`
- **Chain block:** `41554187`
---
## File Mapping
This bundle consists of: `L2-087-001.md`, `L2-087-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-087-001.md` | Source of truth — edit this | Human or LLM |
| `L2-087-001.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 `L2-087-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._