Table 3.

Values and uncertainty estimates (1 σ) for Method 2, irradiation in the Nucletron jig in water. Dwell times were calculated to deliver 1 Gy. The measured dose was 1.011 Gy (i.e., 1.1% higher than predicted). The uncertainty in d is estimated to be 0.5 mm, resulting in a 2% uncertainty in the calculated absorbed dose.

Quantity	Value	Units	Uncertainty in ${\mathrm{D}}_{\mathrm{w}}$ (%)
Calculation of $D_w$ from AKR
AKR (at 1 m)	$8.85\times {10}^{-6}$	$\text{Gy}\hspace{0.17em}{\mathrm{s}}^{-1}$	1
Distance d in water	50	mm	2
Dose at 50 mm per unit air kerma at 1 m, R	446		2
Dwell time for 1 $\text{Gy}=1/(R\times AKR)$	253.3	s	3%
Measurement with ionisation chamber
$M_u$	$1.81\times {10}^{-8}$	C	< 0.1
$k_{TP}{k}_{elec}$	1.006		0.1
$N_D$ calculated by TRS‐277 from $N_{k,Ir-192}$	$4.74\times {10}^7$	$\text{Gy}\hspace{0.17em}{\mathrm{C}}^{-1}$	1
Average stopping power ratio, water to air, s	1.137		0.3
$p_{Wall}$	0.99		0.5
$p_{cel}$	0.98		0.5
$p_n(=k_n)$	1.035		1
Distance d in water	50	mm	2
$D_w=M_u\times k_{TP}{k}_{elec}\times N_D\times s\times p_{nwall}\times p_{ncel}\times p_n$	1.011	Gy	3%