# 📐  L2 Spec — Photon-Counting CT (PCCT) — spectral detector CT Mismatch-Only Spec

**ID:** `L2-054-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-054`](/artifact/l1/L1-054)

> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41553361

---

## 1. Domain Ω

**Type:** `range`

| Parameter | Unit | Range |
|---|---|---|
| H | px | 256 |
| W | px | 256 |
| Z | — | 64 – 2048 |
| Mas | — | 1 – 500 |
| Pixel mm | mm | 0.05 – 1.0 |
| Pulse pileup | — | 0.0 – 0.5 |
| N energy bins | — | 2 – 16 |
| N projections | — | 180 – 2880 |
| Beam hardening | — | 0.0 – 0.3 |
| Charge sharing | — | 0.0 – 0.3 |
| K edge calibration | — | 0.0 – 0.1 |

## 2. Tolerance (ε)

**Type:** `fn`

```
20.0 + 2.0 * log10(mAs / 1) - 10.0 * charge_sharing - 15.0 * pulse_pileup - 8.0 * beam_hardening
```

## 3. Difficulty

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

## 4. Fingerprint

`05ea4e4af9bd49e299bda28b94d79b8a00b2753cdc6a6d911a9609c8d1a3e9d3`

## 5. On-chain Registration

- **Chain hash:** `0x9c48f465cffdc74ef7e0b72deee682965aff864afcff4d8975a9ee9c9e49d071`
- **Chain tx hash:** `0xfd11915cef9f6b78aeee677a48484caa9a9fc8ab0bfc12547bf18eceba0cc7b1`
- **Chain block:** `41553361`

---

## File Mapping

This bundle consists of: `L2-054-001.md`, `L2-054-001.json`.

| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-054-001.md` | Source of truth — edit this | Human or LLM |
| `L2-054-001.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 `L2-054-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._