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pith:OR3X7UDA

pith:2026:OR3X7UDAP2ITJFRPYIKKHX57NS

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PyNMC: An Open-Source Framework for Neutron Multiplicity Counting Simulation Coupling OpenMC, FREYA, and ALPHANSO

Christopher Fichtlscherer

Open-source PyNMC framework simulates neutron multiplicity counting by coupling OpenMC, FREYA and ALPHANSO and matches ESARDA benchmark results.

arxiv:2605.17440 v1 · 2026-05-17 · physics.ins-det · physics.comp-ph

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Claims

C1strongest claim

The framework is validated against the ESARDA Neutron Multiplicity Benchmark on bare 252Cf, low-multiplication Pu metal (M=1.12), and 10 g PuO2 with alpha-n source; simulated rates agree with point-model predictions and published ESARDA participant-code scatter.

C2weakest assumption

The couplings between OpenMC transport, FREYA event-by-event emission, ALPHANSO alpha-n estimates, and the custom collision-level time-tagged recording plus Python shift-register post-processor introduce no significant artifacts or biases relative to the physics of real detectors.

C3one line summary

PyNMC delivers a Python-native open-source NMC simulation framework coupling OpenMC, FREYA, and ALPHANSO, validated on ESARDA benchmarks for Cf-252 and Pu samples with agreement to point models and participant codes.

References

26 extracted · 26 resolved · 0 Pith anchors

[1] MCNP-PoliMi: a Monte-Carlo Code for Correlation Measurements, 2003

[2] Simulation of Neutron Multiplicity Measurements using Geant4 — Open Source Software for Nuclear Arms Control, 2016

[3] Application Guide to Neutron Multiplicity Counting, 1998

[4] Nuclear Warhead Verification: A Review of Attribute and Template Systems, 2015

[5] Reducing Neutron Multiplicity Counting Bias for Plutonium Warhead Authentica - tion, 2015

Receipt and verification

First computed	2026-05-20T00:04:38.948806Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

74777fd0607e9134962fc214a3dfbf6c8368acc1fb9c8f821eba4318a7a1dab4

Aliases

arxiv: 2605.17440 · arxiv_version: 2605.17440v1 · doi: 10.48550/arxiv.2605.17440 · pith_short_12: OR3X7UDAP2IT · pith_short_16: OR3X7UDAP2ITJFRP · pith_short_8: OR3X7UDA

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Verify this Pith Number yourself

curl -sH 'Accept: application/ld+json' https://pith.science/pith/OR3X7UDAP2ITJFRPYIKKHX57NS \
  | jq -c '.canonical_record' \
  | python3 -c "import sys,json,hashlib; b=json.dumps(json.loads(sys.stdin.read()), sort_keys=True, separators=(',',':'), ensure_ascii=False).encode(); print(hashlib.sha256(b).hexdigest())"
# expect: 74777fd0607e9134962fc214a3dfbf6c8368acc1fb9c8f821eba4318a7a1dab4

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "901b81b066be60a3c4c5a698026fe7d420d7b30f17939fdf1c176404c0d305e5",
    "cross_cats_sorted": [
      "physics.comp-ph"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "physics.ins-det",
    "submitted_at": "2026-05-17T13:25:32Z",
    "title_canon_sha256": "31152202f5d63e0fcc7a9cf1bd0818e2a24f30d9b08c3bd46345a5a2498eaa2b"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2605.17440",
    "kind": "arxiv",
    "version": 1
  }
}