Question

(a) Explain the features of the spectra of alpha, beta and gamma radiation.

(b) Why does alpha/beta spectroscopy have to be conducted in an environment different from that for gamma spectroscopy?

Answer 1

a) The ability of radiation to damage molecules is analysed as Ionizing power. The ionizing radiation takes in form of alpha, beta and gamma radiation.

All types are caused by unstable atoms by excess of energy or mass. To reach stable state, must releases that extra energy or mass in the form of radiation.

(i) Alpha Radiation : Emission of alpha particles from the nucleus of an atom. Due to their charge and mass, alpha particles interact strongly with matter, and only travel a few cm in air.

• Not able to penetrate skin.
• harmful to humans if the materials are inhaled or absorbed through open wounds.
• minimally penetrating into the blood, water and paper and its difficult to detect by instruments.

(ii) Beta Radiation : High energy emitted from the nucleus. Emission of beta particles from the nucleus of an atom. Due to the smaller mass, able to travel few meters in air and can be stopped by a thick piece of plastics, stack of paper

• penetrate human skin where the skin cells are produced. if the contaminants are remain on the skin for long period of time, may cause skin damage.
• can detected with survey instruments. but sometimes its difficult to detect due to low emission of energy.

(iii) Gamma Rays : In a high energy form electromagnetic radiation(not a particles). No charge or mass consists of photon of energy released from unstable nucleus.

• Can travel much farther through air.
• Can stop penetrating by a thick or dense layer with high atomic number particles such as concrete, steel, Lead or depleted uranium.