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0008 — Deep-LASI → Tether correction-factor naming remap (β→α, α→δ, γ→γ)

  • Status: accepted
  • Date: 2026-06-24
  • Deciders: bioedca
  • PRD anchor: Appendix B.1 (naming map), §7.2; FR-CORRECT, FR-LEGACY
  • Milestone: M0.5 (decode) → M3 (apply)

Context and problem statement

Tether adopts the field-standard α/δ/γ convention [Hellenkamp2018][Lee2005]: α = donor→acceptor leakage (additive), δ = direct excitation (= 0, single-laser), γ = detection/QY ratio (multiplicative). Deep-LASI's internal MATLAB naming is inverted: its stored Beta holds leakage and its stored Alpha holds direct excitation. When importing Deep-LASI .tdat/.mat factors, how do we map them without silently corrupting E?

Decision drivers

  • Misattributing Deep-LASI's Beta (leakage) drops a real leakage correction and shifts every imported E.
  • Folding leakage into γ would double-count and is physically wrong.
  • The remap must be explicit, unit-tested, and documented next to the importer.

Considered options

  • A. Explicit remap on import — Deep-LASI β → Tether α (apply, additive); Deep-LASI α → Tether δ (inert / 0, ALEX-only); γ → γ. A unit test asserts β is never folded into γ and Deep-LASI α is never treated as Tether α.
  • B. Pass factors through by name (wrong — inverts leakage vs direct excitation).
  • C. Re-estimate all factors natively, ignoring imported ones (loses legacy calibration).

Decision outcome

Chosen option: A. The tether.io importer applies the remap (PRD Appendix B.1); δ is carried as inert 0 in the single-laser 2-color scheme; the load-bearing correction order is background → α → δ(0) → γ (Appendix B.2).

Consequences

  • Good: imported Deep-LASI results match Tether's native convention; no silent E shift.
  • Trade-off: importer must track source provenance and the remap explicitly.
  • Follow-up: a remap unit test (β never folded into γ) lands with the M0.5 .tdat decode and is re-exercised at M3/M7.

More information

PRD Appendix B.1/B.2; deeplasi/functions/deeplearning/deep_autocorrect_2color.m; deeplasi/functions/traces/manualCorrectionFactors.m; PLAN M0.5 S6, M3.