nds-doi-lookup

name	nds-doi-lookup
description	Use this skill when looking up and verifying DOIs for the most recent Nuclear Data Sheets (NDS) evaluation articles by mass number A. Uses the NNDC EvaluationIndexServlet as ground truth, Crossref REST API for DOI discovery, and the Elsevier linking hub for confirmation. Inserts verified DOI lines in ascending A order into Data Check Report .txt files.
argument-hint	["space-separated list of mass numbers","e.g. 204 207 208 211 212"]

NDS DOI Lookup Skill

ENSDF 80-column data record and field definitions, structural rules, column positions, and uncertainty notation: .github/agents/ENSDF-Agent.agent.md. Spot-check policy: .github/copilot-instructions.md.

Critical Rule: NNDC EvaluationIndexServlet Is the ONLY Ground Truth

MANDATORY FIRST STEP for any citation lookup or verification task: fetch the NNDC Evaluation Index and inspect the citation field.

fetch https://www.nndc.bnl.gov/ensdf/EvaluationIndexServlet

Each MASS entry in the returned JSON has a citation field with two possible forms:

citation value	Meaning	Action
"ENSDF"	Continuous internal ENSDF evaluation -- no published journal paper is the current authoritative source. Old journal papers for this A exist but are superseded.	Set citation to "Continuous internal ENSDF", blank DOI, blank or known evaluator name. Never substitute an old Crossref paper.
"NDS vol, page (year)"	A specific published NDS paper is the current evaluation.	Use Crossref to find the DOI for that exact citation, then record it.

CRITICAL: Many mass chains (e.g., A=77, 101, 108, 117, 165, 224 as of 2025) are marked "citation":"ENSDF" in the NNDC index. These chains have older published papers in Crossref, but those papers are no longer the current evaluation. Do NOT use them. The NNDC index is the only authoritative source for which papers are current.

Always re-fetch the NNDC index live -- never rely on hardcoded or cached data, as the index is updated when new evaluations are published (e.g., A=216, 261, 265 switched from old papers to new NDS vol.209 (2026) papers during the 2025 evaluation cycle).

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Workflow

1. Retrieve Ground Truth from NNDC

fetch https://www.nndc.bnl.gov/ensdf/EvaluationIndexServlet

Parse the resulting JSON. For type=MASS entries, extract the citation field for the desired mass number(s).

• If citation == "ENSDF": record as continuous internal ENSDF -- stop here, no DOI needed.
• If citation is a journal reference ("NDS vol, page (year)"): proceed to Step 2.

2. Discover DOI via Crossref

Using the exact citation details from NNDC, query Crossref with the ISSN filter for Nuclear Data Sheets (issn:0090-3752) and volume:

https://api.crossref.org/works?query.bibliographic={journal}+{volume}+{page}+{year}&rows=20&filter=issn:0090-3752

Extract the item whose page field starts with the target page number. Read off DOI and author list.

Note: The filter=container-title:Nuclear+Data+Sheets syntax causes HTTP 400 errors. Use filter=issn:0090-3752 instead. For very recent publications (current year), prefer filter=issn:0090-3752,from-pub-date:{year-1} to limit the result set.

3. Insert into Report or Table

Insert one line per mass number in ascending A order:

Nuclear Data Sheets for A={A} https://doi.org/{DOI}

Match the formatting of any pre-existing entries in the file. After editing, read back the modified section to confirm all entries are present, correctly ordered, and surrounding text is intact.

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Pitfalls

Pitfall	Mitigation
Using old Crossref papers for ENSDF-tagged chains	Fatal error. Always check NNDC citation field first. If "ENSDF", the old paper is superseded -- never use it.
Hallucinated or missing A<45 masses	Never search by title alone; always use NNDC EvaluationIndexServlet as ground truth.
Stale hardcoded NNDC data	Always re-fetch live; new evaluations are published frequently (e.g., A=216,261,265 switched to NDS 209 (2026)).
Crossref rate limiting / silent drops	Use sequential fallback limits; handle HTTP Error 400; avoid aggressive multithreading.
filter=container-title: in Crossref URL	Causes HTTP 400. Use filter=issn:0090-3752 instead.
URL encoding errors	Carefully encode citation strings in query.bibliographic requests.
Non-NDS journals	Light mass chains often resolve to "Nuclear Physics A" (NP A) rather than "Nuclear Data Sheets" (NDS).
Grouped evaluations (one paper covers multiple A)	One DOI may serve multiple A values (e.g., NDS 209, 499 covers A=261 and A=265). Both rows get the same DOI.