Uncertainty Components Evaluated for Determination of Total Activity Contained in NIST-Prepared 68Ge Epoxy–Filled Syringes
| Component, ui | Comment | Magnitude (%) |
|---|---|---|
| SSIC chamber calibration factor | Combined standard uncertainty on activity of solution-filled sources used to derive calibration factor | 0.47 |
| Current measurement repeatability | SD of mean on 10 measurements of current for single source | 0.21 |
| Background variability | SD of mean on 1,000 measurements of background current for single source | 2.00E−02 |
| Decay correction | Standard uncertainty in half-life (0.059%) over measurement decay interval | 2.40E−03 |
| Current measurement reproducibility | SD on 2 measurements of each source; typical value | 0.04 |
| Combined (uc = √Σui2) | 0.52 |