Cadmium correction factors of several thermal neutron foil detectors

If the epithermal activation C_ep of a foil detector is derived from its epicadmium activation C_Cd, the knowledge of the cadmium correction factor $\text{F}{}_{\mathrm{<mtext>Cd</mtext>}}\text{=}\text{C}{}_{\mathrm{<mtext>ep</mtext>}}\text{C}{}_{\mathrm{<mtext>Cd</mtext>}}$ is usually required. The cadmium correction factors of V, B, ¹⁰B, In, Au, Mn, Co, and Dy foil detectors of thickness 0·0·25 mm and cadmium cover thicknesses of 0·5, 0·8, 1·0, and 1·2 mm have been numerically evaluated according to the most recent cross-section values and resonance parameters. F_cd values are listed for both monodirectional and isotropic neutron incidence. While for most of these materials no results have been published so far, for gold and indium the results could be compared with previous calculations and measurements and a discussion of the results is given. Since the F_Cd values, particularly for Mn, Co, and Dy, exceed unity considerably, neglecting this correction is not tolerable with precise measurements of the thermal neutron flux density. Comments on the use of F_Cd values in the Westcott convention are added.