Nuclear Physics

First three Lectures

Muhammad Zeeshan Khalid

Radioactive Decay

• Radioactive decay, also known as nuclear decay or

radioactivity, is the process by which a nucleus of an unstable

atom loses energy by emitting particles of ionizing radiation. A

material that spontaneously emits this kind of radiation—

which includes the emission of energetic alpha particles, beta

particles, and gamma rays—is considered radioactive.

Radioactive decay results in the emission of either:

• an alpha particle (a),

• a beta particle (b),

• or a gamma ray(g).

Radioactive Decay

1. Neutron cross section

• In nuclear and particle physics, the concept of a neutron cross

section is used to express the of interaction between an

incident neutron and a target nucleus.

• Microscopic cross scattering does provide no information

about the change in neutron direction or energy that occur in

such collision.

Microscopic Cross Section

Macroscopic Cross Section

Neutron-Nuclear Interaction

Potential Scattering: Neutron scatter elastically off the

nucleus

Compound Nucleus: Neutron absorbed by the nucleus to

form compound nucleus and then decay an energetic particle.