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v1.7.5 - SRIM Stopping-Power Cross-Check

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@MarkWSavage MarkWSavage released this 20 Jul 03:31

Adds an independent SRIM stopping-power cross-check for all six heavy-ion primaries, complementing the existing nuclear-reaction-focused validations (CREME-MC, McNulty/CUPID, Hitachi).

SRIM stopping-power cross-check

  • Macros/run_<ion>_srim_check.mac: a small (1000-event), unbiased run per ion, deliberately sized so direct ionization dominates the mean deposited energy and rare nuclear reactions stay statistically negligible.
  • Mean deposited energy through the standard 8 um Si sensitive volume converts to an implied LET, compared against SRIM's reported electronic stopping power for the same ion/energy/material (15 MeV/amu each):
Ion Energy PANDA LET (MeV*cm2/mg) SRIM (MeV*cm2/mg) Ratio
C12 180 MeV 0.884 0.906 0.976
F19 285 MeV 1.966 2.029 0.969
Cl35 525 MeV 6.606 6.732 0.981
Ni58 870 MeV 15.924 16.23 0.981
I127 1905 MeV 42.736 48.92 0.874
Au197 2955 MeV 74.147 77.90 0.952
  • Five of six agree within 5%; I127 is the outlier at 13%, investigated and attributed to ordinary Geant4-vs-SRIM stopping-power model variation rather than a methodology artifact (its shorter range relative to the dead+sensitive stack was ruled out as the cause -- too small a range fraction to matter).
  • Full writeup in Documentation/PANDA_VALIDATION_SUMMARY.md Section 1.4.

See README.md for details.