Struct ResolutionParams 

pub struct ResolutionParams { /* private fields */ }

Resolution function parameters for time-of-flight instruments.

Implementations

impl ResolutionParams

pub fn new( flight_path_m: f64, delta_t_us: f64, delta_l_m: f64, delta_e_us: f64, ) -> Result<Self, ResolutionParamsError>

Create validated resolution parameters.

delta_t_us and delta_l_m are W-parameters (σ = W/√2), not standard deviations. If your instrument numbers are 1σ or FWHM, use from_sigma or from_fwhm instead of converting by hand.

Arguments

• flight_path_m — Flight path length in meters (must be > 0).
• delta_t_us — Timing width in microseconds, W-parameter (must be >= 0).
• delta_l_m — Flight path width in meters, W-parameter (must be >= 0).
• delta_e_us — Exponential tail parameter in SAMMY Deltae units (must be >= 0). When 0, pure Gaussian broadening is used.

Errors

Returns ResolutionParamsError::InvalidFlightPath if flight_path_m <= 0.0 or is not finite. Returns ResolutionParamsError::InvalidDeltaT if delta_t_us < 0.0 or is not finite. Returns ResolutionParamsError::InvalidDeltaL if delta_l_m < 0.0 or is not finite. Returns ResolutionParamsError::InvalidDeltaE if delta_e_us < 0.0 or is not finite.

pub fn from_sigma( flight_path_m: f64, sigma_t_us: f64, sigma_l_m: f64, delta_e_us: f64, ) -> Result<Self, ResolutionParamsError>

Create resolution parameters from standard deviations.

Instrument metrology is usually quoted as a 1σ jitter, while this type stores W-parameters. This constructor applies W = σ·√2 to the timing and flight-path terms, so a measured 1σ can be passed in directly.

delta_e_us is not a Gaussian width — it is SAMMY’s exponential tail parameter Deltae — so it is passed through unchanged.

Errors

Same as new, on the converted values.

pub fn from_fwhm( flight_path_m: f64, fwhm_t_us: f64, fwhm_l_m: f64, delta_e_us: f64, ) -> Result<Self, ResolutionParamsError>

Create resolution parameters from full widths at half maximum.

Applies W = FWHM/(2·√(ln 2)) to the timing and flight-path terms. This is the measure SAMMY’s Deltag uses, so a value taken from a SAMMY .inp timing field can be passed in directly.

delta_e_us is SAMMY’s exponential tail parameter, not a Gaussian width, so it is passed through unchanged.

Errors

Same as new, on the converted values.

pub fn flight_path_m(&self) -> f64

Returns the flight path length in meters.

pub fn delta_t_us(&self) -> f64

Total timing width in microseconds, as a W-parameter (σ = W/√2).

The factor of 2 in gaussian_width() comes from the energy-TOF derivative dE/E = 2·dt/t, not from a width-measure conversion — the convention is unchanged between time and energy.

pub fn delta_l_m(&self) -> f64

Returns the flight path width in meters, as a W-parameter (σ = W/√2).

pub fn delta_e_us(&self) -> f64

Returns the exponential tail parameter (SAMMY Deltae units).

pub fn has_exponential_tail(&self) -> bool

Whether the exponential tail is active (Deltae > 0, SAMMY Iesopr=3).

pub fn exp_width(&self, energy_ev: f64) -> f64

Exponential tail width Widexp(E) in eV.

SAMMY Ref: rsl/mrsl4.f90 Wdsint lines 55-56 (Kedxfw=false path): Widexp = E * Co2 * sqrt(E) where Co2 = 2·Deltae / (Sm2·Dist).

Combined: Widexp = 2·Deltae·E^(3/2) / (TOF_FACTOR·L).

pub fn gaussian_width(&self, energy_ev: f64) -> f64

Gaussian resolution width W_g(E) in eV — the W of exp(-x²/W_g²).

Combines timing and flight-path contributions in quadrature: W_g² = (2·Δt/t × E)² + (2·ΔL/L × E)²

where t = TOF_FACTOR × L / √E is the time-of-flight in μs. Δt and ΔL are W-parameters too, so the convention carries through unchanged; the standard deviation is W_g/√2 and the FWHM is fwhm.

pub fn fwhm(&self, energy_ev: f64) -> f64

FWHM of the resolution function at energy E, in eV.

FWHM = 2·√(ln 2)·W, the conversion for exp(-x²/W²). For the standard deviation instead, use gaussian_width(E)/√2.

Trait Implementations

impl Clone for ResolutionParams

fn clone(&self) -> ResolutionParams

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ResolutionParams

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Copy for ResolutionParams