Table 2.

Sources of Uncertainty and Their Impacts on the Index Uncertainty

Sources $x$	Magnitude of Uncertainty $u(x)$	Index Uncertainty $u_x(n)\left({10}^{-5}\right)$
Peak position	(0.7 to 5) arcseconds (1/10th of diffracted peak width FWHM)	0.6–4
Prism apex angle	0.15 arcseconds [including λ/120 (at 633 nm) RMS surface flatness error]	0.9
Index inhomogeneity	0.91 × 10−5 RMS for 10 mm thickness at λ= 3.39 μm	0.91
Encoder angle	0.15 arcseconds	0.17
Prism temperature	0.005°C	0.26–0.20
Wavelength calibration	0.05 nm	0.6–0.002
Alignment	0.05 arcseconds	0.08
N2 gas and air dispersion formulas	2 × 10−7	0.08
N2 gas temperature	0.02°C	0.01
N2 gas pressure	0.02 kPa	0.02