Radioactivity

3. material that can stop all types of nuclear radiation
8. device used to detect nuclear radiation
10. the unwanted presence of materials containing radioactive atoms on other materials
11. piece of personal protective equipment that consists of an impermeable whole-body garment worn as protection against hazardous materials
13. type of nuclear radiation with a negative charge
14. type of nuclear radiation with the least penetrating power
16. the rate at which a source of unstable nuclei decays
18. nature of radioactive decay

1. unit of measurement for radioactivity
2. the time it takes for the count rate (or activity) from a sample containing the isotope to fall to half its initial level
4. process by which electrically neutral atoms or molecules are converted to electrically charged atoms or molecules (ions) through gaining or losing electrons
5. type of nuclear radiation with the highest range in air
6. type of nuclear radiation without mass or charge
7. type of nuclear radiation with the most ionising power
9. the process of exposing an object to nuclear radiation
12. type of nuclear radiation with the lowest range in air
15. the number of decays recorded each second by a detector
17. versions of an element with the same number of protons but a different number of neutrons