Nuclear Radiation

Unstable isotopes emit radiation Radiation: rays and particles emitted by unstable elements. They decay based on their half-lives

Radiation can be natural or man-made

2 types of Radiation: Electromagnetic Radiation : Pure energy Consisting of interacting electrical & magnetic waves Oscillating in space Radio, microwave, infrared, visible light, Gamma, X-ray, UV with high energy

2. Nuclear Radiation : Atomic Nucleus Proton + Neutron  Nuclear forces Some isotope didn’t stable  they will randomly eject matter or energy to achieve greater stability  Radioactive. Example: Uranium U-235 release neutrons and gamma ray photons.

Ionizing radiation: Nuclear Radiation - An atom has lost or gained electron  ion has enough energy to ionize matter Can produce free radicals (molecules with unpaired electrons) which can cause cancer. Geiger counter can detect it Examples are alpha, beta, gamma, x-rays, UV light

non-ionizing radiation: Electromagnetic radiation (longwave length) low energy Just excite electrons Examples are: Solar (visible light), radio broadcast, TV broadcast, microwave, and heat

3 most common types of Radiation: Alpha Particle, Beta Particles, and Gamma Rays Alpha Particle () : (same as helium atom) Symbol: Charge: +2 charge Energy: low Movement: SLOW Penetration: little (blocked by paper) Example: Alpha Decay: An alpha particle is released 5

An alpha particle 2 proton and 2 neutrons bound together and is emitted from the nucleus during some kinds of radioactive decay.

Beta Particle (β) : ionizing Beta particles Symbol: 0-1β or 0-1e Charge: -1 Energy: medium Movement: Fast Penetration: Medium (blocked by metal foil) Example: Beta Decay: electron is ejected from nucleus, neutron becomes proton

Beta Emission An electron emitted from the nucleus during some kinds of radioactive decay. 10 n  11 p + 0-1β Nuclides above the band of stability are unstable because n/p is too large. To decrease the number of neutrons, a neutron can be converted into a proton and an electron. The electron is emitted from the nucleus as beta particle.

Gamma () rays: ionizing Symbol: 00 Charge: 0 Energy: very high Movement: Very Fast (speed of light) Penetration: FAR! (Only blocked by thick lead/concrete) Example: Gamma Decay: High energy photons (electromagnetic radiation) are given off

Gamma Emission High energy electromagnetic waves emitted from a nucleus as it changes from an excited state to a ground energy state.

Penetration of 3 types of radiation

Two additional types of Decay with Beta… Positron Emission: An antielectron is given off from the nucleus and a proton becomes a neutron Symbol: 0+1e or 0+1β Charge: +1

Positron Emission 11 p  10 n + 0+1β A positron is a particle that has the same mass as an electron, but has a positive charge and is emitted from the nucleus during some kinds of radioactive decay. 11 p  10 n + 0+1β Nuclide below the band of stability are unstable because their n/p is too small. To decrease the number of protons, a proton can be converted into a neutron by emitting a positron.

Electron capture: An inner orbital electron is pulled /captured by the nucleus and combines with a proton become a neutron Symbol: 0-1e Charge: -1

This electron capture : n/p is too small 0-1 e + 11 p  10 n

Nuclear Reaction Nuclear Fission and Fusion What do you think about when you hear these terms?

Nuclear Reactions - Reactions involving changes in the nucleus of atoms - These reactions release MUCH MORE energy then chemical reactions (which deal with electrons only)

Two major types of nuclear reactions: Fission Fusion

Nuclear Fission Nuclear fission = splitting of large, unstable atoms Releases large amounts of energy Uncontrolled, nuclear fission proceeds to completion with great speed.

Nuclear Fusion Nuclear Fusion: Joining of smaller nuclei to form larger nuclei. Releases far more energy than nuclear fission (3-4 xs more). Unlike fission, fusion reactions can be easily controlled, by controlling the fuel flow.