openmc.stats.fusion_neutron_spectrum
- openmc.stats.fusion_neutron_spectrum(ion_temp: float, reactants: str = 'DD', bias: Univariate | None = None) Normal[source]
Return a Gaussian energy distribution for fusion neutron emission.
Computes the mean energy and spectral width of the neutron energy spectrum from thermonuclear fusion reactions in a plasma with Maxwellian ion velocity distributions. The mean neutron energy is calculated as
\[\langle E_n \rangle = E_0 + \Delta E_\text{th}\]where \(E_0\) is the neutron energy at zero ion temperature and \(\Delta E_\text{th}\) is the thermal peak shift due to the motion of the reacting ions. The spectral width is characterized by the FWHM:
\[W_{1/2} = \omega_0 (1 + \delta_\omega) \sqrt{T_i}\]where \(\omega_0\) is the width at the \(T_i \to 0\) limit and \(\delta_\omega\) is a temperature-dependent correction term. Both \(\Delta E_\text{th}\) and \(\delta_\omega\) are evaluated using interpolation formulas from Ballabio et al.: Table III for \(0 < T_i \le 40\) keV and Table IV for \(40 < T_i < 100\) keV. The returned distribution is a normal (Gaussian) approximation to the spectrum.
Added in version 0.15.4.
- Parameters:
ion_temp (float) – Ion temperature of the plasma in [eV].
reactants ({'DD', 'DT'}) – Fusion reactants. ‘DD’ corresponds to the D(d,n)3He reaction and ‘DT’ to the T(d,n)\(\alpha\) reaction.
bias (openmc.stats.Univariate, optional) – Distribution for biased sampling.
- Returns:
Normal distribution with mean and standard deviation corresponding to the first and second moments of the fusion neutron energy spectrum. Both the mean and standard deviation are in [eV].
- Return type: