Constant DEFAULT_PSR_FWHM_NS 

pub const DEFAULT_PSR_FWHM_NS: f64 = 350.0;

Default SNS PSR (proton-storage-ring / accumulator) channel-triangle FWHM in ns, folded into the IC family’s kernel. The SNS proton pulse is shaped by the accumulator ring into an ~triangular ~700 ns base (FWHM ≈ 350 ns) — the VENUS tabulated FTS kernel header records exactly this (“folded triang FWHM 350 ns PSR”). SAMMY’s analog is the Gaussian-burst FWHM DELTAG (Manual Sec. III.C.1.a, eq. III C1 a.12) or square BURST width (Sec. III.C.2.a). pub so the Python binding’s default and the Rust default cannot drift apart.