7.7 - Half-Life & Hazard
Half-life and activity determine the hazard
- How dangerous a radioactive source is depends on both its activity and its half-life.
- The lower the activity, the safer it is to be near.
Why half-life matters over time
- For two sources of the same radiation type and initial activity, the one with the longer half-life remains hazardous for much longer.
- A source with a short half-life has its activity fall quickly, while a source with a long half-life stays radioactive for decades or centuries.
- Sources with long half-lives therefore require secure, long-term shielding and disposal.