radioactive decay and stability

what causes beta radioactive decay

Cause: The nucleus has an unstable combination of too many neutrons

Goal: The nucleus undergoes a change to get rid of the extra neutrons and become more stable.

types of radiation emitted during decay

alpha, beta, gamma

half life definition

the time taken for half of the radioactive atoms in a sample to decay (can be minutes, days, years or thousands of years)

Half-life vs. Safety (Key relationship)

Short half-life: Atoms decay more quickly and become safe much faster (loses radioactivity rapidly).

Long half-life: Atoms decay more slowly and remain radioactive for longer.

Does half-life alone determine how dangerous a source is?

No - other critical factors: dose, activity, radiation type, exposure

Ionising radiation

Definition: Radiation with enough energy to ionise atoms and molecules.

Mechanism: Passes through matter and interacts with biological molecules (including DNA).

Cell Impact: Causes changes to cells.

diseases contributed to by ionising radiation

• Cell/Blood: Cancer, leukaemia, and other blood disorders.

• Body: Skin burns and eye cataracts.

radiation uses: sterilisation

Kills microorganisms on surgical instruments

radiation uses: cancer treatment

Gamma radiation kills cancerous tumour cells (Goal: limit damage to healthy tissue).

radiation uses: medical imaging

A patient takes a small gamma radioisotope (tracer) that passes out of the body to be detected by a camera, using a short half-life to keep cell damage minimal

radioisotopes

unstable isotopes that undergo radioactive decay to become stable

gamma radiation

high energy electromagnetic wave, 0 electric charge, high penetrating ability, shielded/stopped by thick lead or dense concrete

beta radiation

high speed electron emitted from nucleus, -1 electric charge. moderate penetrating ability, shielded/stopped by a thin sheet of aluminum

alpha radiation

helium nucleus (2 protons, 2 neutrons), 2+ electric charge. low penetrating ability. shielded/stopped by paper, human skin or human hands

how beta decay results in a stable atom

The Process: A neutron turns into a proton, shooting out a high-energy electron (the beta particle).

The Result: The atomic number increases by 1, creating a new element with a perfectly stable neutron-to-proton balance.