Experiment

class iadpython.iad.Experiment(r=None, t=None, u=None, sample=None, r_sphere=None, t_sphere=None, num_spheres=0, default_a=None, default_b=None, default_g=None)

Bases: object

Container class for details of an experiment.

Methods Summary

check_measurements()	Make sure measurements are sane.
determine_one_parameter_search()	Establish proper search when only one measurement is available.
determine_search()	Determine type of search to do.
determine_two_parameter_search()	Establish proper search when 2 or 3 measurements are available.
invert_rt()	Find a,b,g for experimental measurements.
invert_scalar_rt()	Find a,b,g for a single experimental measurement.
measured_rt()	Calculate measured reflection and transmission.
useful_measurements()	Count the number of useful measurements.
what_is_b()	Find optical thickness using unscattered transmission.

Methods Documentation

check_measurements()

Make sure measurements are sane.

determine_one_parameter_search()

Establish proper search when only one measurement is available.

determine_search()

Determine type of search to do.

determine_two_parameter_search()

Establish proper search when 2 or 3 measurements are available.

invert_rt()

Find a,b,g for experimental measurements.

This method works if m_r, m_t, and m_u are scalars or arrays.

Returns:

• a is the single scattering albedo of the slab

• b is the optical thickness of the slab

• g is the anisotropy of single scattering

invert_scalar_rt()

Find a,b,g for a single experimental measurement.

This routine assumes that m_r, m_t, and m_u are scalars.

Returns:

• a is the single scattering albedo of the slab

• b is the optical thickness of the slab

• g is the anisotropy of single scattering

measured_rt()

Calculate measured reflection and transmission.

The direct incident power is \((1-f)P\). The reflected power will be \((1-f)R_{direct} P\). Since baffles ensure that the light cannot reach the detector, we must bounce the light off the sphere walls to use to above gain formulas. The contribution will then be

\[(1-f)R_{direct} (1-a_e) r_w P.\]

The measured power will be

\[P_d = a_d (1-a_e) r_w [(1-f) r_{direct} + f r_w] P ⋅ G(r_s)\]

Similarly the power falling on the detector measuring transmitted light is

\[P_d'= a_d' t_{direct} r_w' (1-a_e') P ⋅ G'(r_s)\]

when the entrance port in the transmission sphere is closed, \(a_e'=0\).

The normalized sphere measurements are

\[M_R = r_{std}⋅\frac{R(r_{direct},r_s)-R(0,0)}{R(r_{std},r_{std})-R(0,0)}\]

and

\[M_T = t_{std}⋅\frac{T(t_{direct},r_s)-T(0,0)}{T(t_{std},r_{std})-T(0,0)}\]

Parameters:

• ur1 – reflection for collimated incidence

• ut1 – transmission for collimated incidence

• uru – reflection for diffuse incidence

• utu – transmission for diffuse incidence

Returns:

[float, float] – measured reflection and transmission

useful_measurements()

Count the number of useful measurements.

what_is_b()

Find optical thickness using unscattered transmission.