An environmental scientist is investigating the radioactive decay of a gaseous radon isotope sample using a Geiger-Müller (GM) tube and a counter.
State one natural source of background radiation.
Describe the method the scientist should use to measure and correct their experimental results for background radiation.
Before starting the experiment, the scientist measures the background radiation inside the testing room. They record a total of 320320320 counts over a period of 888 minutes. Calculate the average background count rate in counts per minute (cpm).
The scientist then places the radioactive gaseous sample near the GM tube and records the total count rate (including background). At t=0 minutest = 0\text{ minutes}t=0 minutes, the total count rate is 360 cpm360\text{ cpm}360 cpm. At t=12 minutest = 12\text{ minutes}t=12 minutes, the total count rate is 80 cpm80\text{ cpm}80 cpm. Calculate the corrected count rate of the sample at both t=0 minutest = 0\text{ minutes}t=0 minutes and t=12 minutest = 12\text{ minutes}t=12 minutes.
Use your answers to part (ii) to calculate the half-life of this isotope. Show your working.
Iodine-123 is a gamma emitter with a half-life of 13 hours13\text{ hours}13 hours and is commonly used as a medical tracer to investigate thyroid gland function inside the human body. Explain why Iodine-123 is highly suitable for this role. Refer to both its emission type and its half-life in your answer.
