Fig. 6

a–e Recovery coefficients as a function of hot sphere size from three consecutive scans at a single site. Each point represents the mean RC, and error bars represent one standard deviation. The COV for each sphere size and hot sphere activity concentrations are shown in Table 4. f Measurements from raw ¹⁸F data (black line), ¹⁸F data with similar ⁹⁰Y true count statistics (light blue square), and ¹⁸F data with similar true count statistics and randoms fraction to ⁹⁰Y. Again, each point represents the mean RC and error bars represent one standard deviation across the ten 3-s ¹⁸F datasets