def transmission_corrected(
data,
theta_in=0.008,
index_optic=N_HPFS,
index_lab=N_AIR):
"""Return the background subtracted and Fresnel loss corrected internal
transmission coefficient from a set of data in the form
[signal, signal_background, reference, reference_background]
where each element is a 2D list. The first sublist column is the beam
monitor photodiode reading and the second is the downstream photodiode
reading. The Fresnel correction requires the input angle theta_in
(in radians) and the indexes of refraction."""
t_correction, t_correction_error = _fresnel_correction(
theta_in, index_lab, index_optic)
t_raw, t_raw_error = transmission_raw(data)
return (t_raw / t_correction,
ratio_error(t_raw, t_correction, t_raw_error, t_correction_error))
def transmission_raw(data):
"""Return the background subtracted raw transmission coefficient from
a set of data in the form
[signal, signal_background, reference, reference_background]
where each element is a 2D list. The first sublist column is the beam
monitor photodiode reading and the second is the downstream photodiode
reading."""
# averages = [np.mean(i, axis=0) for i in data]
# uncertainties = [np.std(i, axis=0) / np.sqrt(len(i)) for i in data]
backgrounds = [np.mean(i, axis=0) for i in (data[1], data[3])]
intensities = np.array(
[((data[s][:, 1] - backgrounds[s/2][1]) /
(data[s][:, 0] - backgrounds[s/2][0])) for s in (0, 2)])
signal, reference = np.mean(intensities, axis=1)
signal_error, reference_error = (
np.std(intensities, axis=1) / np.sqrt(len(intensities[0])))
return (signal / reference,
ratio_error(signal, reference, signal_error, reference_error))
def transmission_per_unit_length(data, **kwargs):
"""Return the background subtracted and Fresnel loss corrected internal
transmission per unit length from a set of data in the form
[signal, signal_background, reference, reference_background]
where each element is a 2D list. The first sublist column is the beam
monitor photodiode reading and the second is the downstream photodiode
reading.
Keyword arguments:
'length' (0.450): Beam path length in desired units through optic.
'length_error (0.001): Uncertainty on length.
All other keywords are passed to 'transmission_corrected'.
"""
length = kwargs.pop('length', 0.450)
length_error = kwargs.pop('length_error', 0.00001)
t_corrected, t_corrected_error = transmission_corrected(data, **kwargs)
scale = 1.0 / float(length)
scale_error = ratio_error(1.0, float(length), 0, length_error)
t_error = power_error(t_corrected, scale, t_corrected_error, scale_error)
return (t_corrected**scale, t_error)
