  Resonance scattering techniques are often used to study the properties of
atoms and molecules. The Birmingham Solar Oscillations Network (BiSON) makes
use of Resonance Scattering Spectroscopy by applying the known properties of
potassium vapour to achieve ultra-precise Doppler velocity observations of
oscillations of the Sun. We present a model of the resonance scattering
properties of potassium vapour which can be used to determine the ideal
operating vapour temperature and detector parameters within a
spectrophotometer. The model is validated against a typical BiSON vapour cell
using a tunable diode laser, where the model is fitted to observed absorption
profiles at a range of temperatures. Finally we demonstrate using the model to
determine the effects of varying scattering detector aperture size, and vapour
temperature, and again validate against observed scattering profiles. Such
information is essential when designing the next generation of BiSON
spectrophotometers (BiSON:NG), where the aim is to make use of off-the-shelf
components to simplify and miniaturise the instrumentation as much as
practical.
