source_function_K

Physics.Radiation.source_function_K(freq, population_ratio)

Source function for a given population ratio and frequency

Given the ratio of the upper and lower populations per degenerate sublevel and the frequency of the transition, returns the Rayleigh-Jeans approximation of the source function in K.

Note that the population ratio here is not the same as returned by LTE_pop_ratio.

:param freq : frequency of the transition in Hz :type freq : float or int

:param population_ratio : (n_u/g_u)/(n_l/g_l) :type population_ratio : float or rational fraction

Returns

float