A research team is selecting a radioactive tracer for a 12-day survey of liquid moving through a closed industrial processing system. Both tracers emit gamma radiation and will be used with the same detector arrangement.
The tracer activity must be at least 1000 Bq1000\ \mathrm{Bq}1000 Bq at the end of the survey so that it can still be detected.
After the survey, all the tracer-containing liquid is collected in a shielded holding tank. The same containment and release conditions apply to either tracer. The liquid must remain contained until the tracer activity falls below 200 Bq200\ \mathrm{Bq}200 Bq.
| Tracer | Activity at the start of the survey | Half-life |
|---|---|---|
| R | 9600 Bq9600\ \mathrm{Bq}9600 Bq | 4 days |
| S | 2400 Bq2400\ \mathrm{Bq}2400 Bq | 12 days |
Calculate the activity of each tracer at the end of the 12-day survey.
The liquid is checked for release exactly 12 days after the survey ends.
Evaluate which tracer should be selected. Use calculations and both activity requirements in your answer.