Read chamber specification from a spec file.

Parameters

[in,out]	file	Spec file.
[in,out]	chamber	Chamber data.

The chamber model is specified by the parameters:

chamber_vol (real, unit m^3): the volume of the chamber
area_diffuse (real, unit m^2): the surface area in the chamber available for wall diffusion deposition (the total surface area)
area_sedi (real, unit m^2): the surface area in the chamber available for sedimentation deposition (the floor area)
prefactor_BL (real, unit m): the coefficient $k_{\rm D}$ in the model $\delta = k_{\rm D}(D/D_0)^a$ for boundary-layer thickness $\delta$
exponent_BL (real, dimensionless): the exponent in the model $\delta = k_{\rm D}(D/D_0)^a$ for boundary-layer thickness $\delta$