Used file for the fit: SDD_normalized-Efficiency_point-source_with-air_all-levels.csv

parameters
offset a	slope b
-2.56201e-06	0.000149491

Covariance matrix
2.21113e-14	-8.97543e-13
-8.97543e-13	3.79072e-11

used data points for fitting
energy [keV]	efficiency	efficiency error	nuclide
53.16	3.27957e-06	1.6945e-07	Ba133
80.97	8.40303e-07	3.02676e-08	Ba133
26.35	2.61812e-05	1.78636e-06	Am241
33.19	1.37604e-05	1.242e-06	Am241
59.53	2.479e-06	1.67608e-07	Am241
