Table 1.

Solid angle parameters for the three beam sizes used in the measurement. The first column gives the diameter of the upstream/ downstream apertures in units of mm; the second column is the number of Dy images that were acquired; the third column is the solid angle ${\overline{\text{Ω}}}_{\text{AG}}$ of the alpha–gamma alpha detector; and the last column is the resulting efficiency correction.

Collimation	Number of images	${\overline{\text{Ω}}}_{\text{AG}}$	$ϵ$ correction $\left({\overline{\text{Ω}}}_{\text{AG}}/{\text{Ω}}_{\text{AG}}\left(0,0\right)\right)$
15/7	2	0.007 0964 ± 0.000 0003	0.992 049 ± 0.000 04
15/8	3	0.007 0788 ± 0.000 0003	0.989 587 ± 0.000 05
15/10	5	0.007 0517 ± 0.000 0004	0.985 798 ± 0.000 05