# 📐 L2 Spec — XFEL Serial Femtosecond Crystallography (SFX) Mismatch-Only Spec
**ID:** `L2-152-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-152`](/artifact/l1/L1-152)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.55 · **Delta tier:** 5
> **⛓ On-chain block:** 41554232
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| H | px | 512 |
| W | px | 512 |
| Hit rate | — | 0.001 – 0.5 |
| Pulse fs | — | 1 – 100 |
| N patterns | — | 1000 – 10000000 |
| Partial reflection | — | 0.0 – 0.8 |
| Beam pointing jitter | — | 0.0 – 0.5 |
| Detector dynamic range | — | 100 – 100000 |
## 2. Tolerance (ε)
**Type:** `fn`
```
10.0 + 2.0 * log10(N_patterns / 1000) + 4.0 * hit_rate - 8.0 * partial_reflection - 5.0 * beam_pointing_jitter
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.55 |
| Delta tier | 5 |
## 4. Fingerprint
`2a9c9a39599278aa16b09654c8b9a2fe2b5575968b4f7139c1e9f4c388b49676`
## 5. On-chain Registration
- **Chain hash:** `0xeb37b427290c0f6c9756e59b900732932dee170cd0efa14fffee1bd850f59999`
- **Chain tx hash:** `0x9472c807892e26c5d625a496076d35022ea7d6cf4e33eef90fda2ed0d41ae3d8`
- **Chain block:** `41554232`
---
## File Mapping
This bundle consists of: `L2-152-001.md`, `L2-152-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-152-001.md` | Source of truth — edit this | Human or LLM |
| `L2-152-001.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 `L2-152-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._