half-life-lifetime-conversion

name	half-life-lifetime-conversion
description	Update L-record half-life value T and uncertainty DT from adopted cL T$ lifetime values by converting |t to T{-1/2} with ln(2), applying ENSDF uncertainty notation, unit scaling, and validation.
argument-hint	[ENSDF file path]

Sync cL T$ Lifetime to L-Record T/DT Fields

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.

Recommended Operating Procedure

1. Read the adopted lifetime from the first |t=, |t>, or |t< in cL T$.
2. Decode comment uncertainty ({In} or {I+n-m}) in value units.
3. Convert with T{-1/2}=|t|*ln(2); scale uncertainty by ln(2).
4. Choose a natural unit (FS, PS, NS, ...): keep stored value not >100; if converted value is <0.1, scale down when the smaller unit gives <=100.
5. Round value/uncertainty together so DT is valid ENSDF data-field content.
6. Update one L-record at a time, then validate immediately.

Core Rule

cL T$ stores lifetime (|t), but L-record T stores half-life (T{-1/2}).

• Numeric: T{-1/2}=|t|*ln(2).
• Symmetric uncertainty: DT{-1/2}=D|t|*ln(2).
• Asymmetric uncertainty: Min and max are converted separately and then combined.
• Limits preserve direction: |t>... -> T>..., |t<... -> T<....
• Follow uncertainty-in-last-digits notation. See .github/agents/ENSDF-Agent.agent.md § ENSDF Uncertainty Notation Rules.
• Round the T value and DT uncertainty together so DT is a valid 1- or 2-digit.
• Example: |t=649 fs {I190} → T{-1/2}=0.45 PS, DT=13.
• Choose a natural T-field unit by scaling between FS, PS, NS, US, etc. so the stored final value is not >100 or <0.1; if the converted value is >100 or <0.1, scale up or down to the nearest appropriate unit.
  • Example: T{-1/2}=650 FS {I80} should be converted to T{-1/2}=0.65 PS {I8}.
  • Example: T{-1/2}=650 PS {I10} should be converted to T{-1/2}=0.650 NS {I10}.
• Avoid introducing unjustified or misleading extra digits.
• Do not over-truncate digits; keep physically faithful bounds.
• Example: |t<2 fs → T{-1/2}<1.4 FS, not T{-1/2}<1 FS, which would change the original value by 40%.

Validation

• Run a reproducible random spot-check focused on transformation correctness (|t -> T{-1/2}, decoded uncertainty -> DT).
• After each edit: python .github/scripts/ensdf_1line_ruler.py --line "<exact 80-char line>"
• After all edits:
  • python .github/scripts/column_calibrate.py "file.ens"
  • python .github/scripts/check_gamma_ordering.py "file.ens"

Audit Addendum (Recommended)

• Treat cL, 2cL, 3cL, ... as one inseparable comment block before extracting lifetimes or averaging inputs.
• For comments containing weighted average of or unweighted average of, verify the adopted lifetime using:
  • python .github/scripts/Java_Average.py --comment "<full cL T block text>"