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

parameters
offset a	slope b
-0.000404693	0.0222134

Covariance matrix
2.12638e-09	-7.92709e-08
-7.92709e-08	3.17508e-06

used data points for fitting
energy [keV]	efficiency	efficiency error	nuclide
53.15	0.000458913	5.52146e-05	Ba133
80.97	0.000111429	1.28935e-05	Ba133
26.35	0.00415802	0.000544926	Am241
33.2	0.0020077	0.000288299	Am241
59.53	0.000367858	4.80994e-05	Am241
