Table 3.

Experimental input and final results of the delayed coincidence analysis. Both for ${}^{238}$U and ${}^{232}$Th decay chain we quote: the number of parent candidates ($N_P$), net of background subtraction; the number of detected coincidences ($N_C$) with their binomial uncertainties; the ratio between surface and bulk contamination activities (r) and their absolute values ($A_b$, $A_s$). We quote the r result for ${}^{232}$Th chain with an asymmetric uncertainty range to exclude negative non-physical values

Decay chain	${}^{238}\mathrm{U}$	${}^{232}\mathrm{Th}$
$N_P$	$4868\pm 70$	$3118\pm 56$
$N_C$	$4442\pm 20$	$2030\pm 27$
$N_C/N_P$	$(91.2\pm 0.4)\%$	$(65.1\pm 0.9)\%$
r	0.24 $\pm$ 0.06	$0.{03}_{-0.03}^{+0.11}$
$A_b$ ($\mu$Bq)	$146\pm 4$	$108\pm 5$
$A_s$ ($\mu$Bq)	$35\pm 8$	$3_{-3}^{+11}$