Radiation

“Life on earth has developed with an ever present background of radiation. It is not

something new, invented by the wit of man: Radiation has always been there.”

- Eric J. Hall Professor of Radiology, Columbia University

Definition of Radiation

Radiation is a type of energy given up by unstable isotopes.

An isotope is an atom with a different number of neutrons than normal.

Discovery of Radiation

Dec. 22, 1895 - Wilhelm Conrad Roentgen X-Rays of his wife’s hand.

March 1896 – Anoine Henri Becquerel Photographic Plates stored in a drawer with Uranium

crystals.

Feb. 17, 1898 – Marie & Pierre Curie Introduced the term “radio-active”

1911 – Ernest Rutherford Radioactive elements experience “decay” over time.

Electromagnetic Spectrum

Types of Radiation

α - Alpha Particles are stopped by paper. β - Beta Particles are stopped by

aluminum foil. Γ - Gamma Rays are stopped by lead,

steel, & concrete. Protons are stopped by the atmosphere. Neutrons are slowed down and eventually

stopped by water & concrete.

Shielding Radiation

Detecting Radiation

We can NOT use our senses to detect radiation.

We CAN us Geiger Counters & film to detect radiation.

For our protection, we label radioactive substances with the radiation symbol…

Measuring Radiation

The amount of radiation affecting people is measured in units known as millirems.

Most people are exposed to less than 360 millirems per year.

Common Sources of Radiation 68% background radiation (from the

environment) 31% medical treatments/procedures <1% fallout, nuclear industry, etc.

Effects of Exposure

Cell Damage & Death Cancer Radiation Cataracts Radiation Sickness Acute Death

Levels of Exposure

Occupational Limit of 5,000 millirems. Increased Cancer Risk at 10,000 millirems. Radiation Sickness is Possible at over

50,000 millirems of exposure Hair loss, severe blood changes, and

possible death within 2-6 weeks with over 200,000 millirems of exposure.

Half of the patients die within 30 days with exposure over 450,000 millirems.

Uses of Radiation Medicine

X-rays Cancer Treatment Diagnose Diseases

Science Absolute Age

Industry Kills Germs Result of the use of Nuclear Energy

Agriculture Fertilizers Insect Control Food Preservation

Radiation Contradictions

Radiation is a two edged sword: its usefulness in both medicine and anthropological and archaeological studies is undisputed, yet the same materials can be used for destruction.

Human curiosity drove inquiring scientists to harness the power of the atom. Now humankind must accept the responsibility for the appropriate and beneficial uses of this very powerful tool.

Radioactive Materials

Americium – 241: Smoke Detectors Californium – 252: Inspect Luggage Cesium – 137: Cancer Treatment Cobalt – 60: Sterilize Surgical Instruments Krypton - 85: Appliance Indicator Lights Promethium – 147: Electric Blanket Thermostats Thorium – 229: Fluorescent Lights Uranium – 234: Dental Fixtures Uranium – 235: Fuel for Nuclear Power Plants

Do Cell Phones Cause Cancer?

Nuclear Energy

Fission vs. Fusion

Nuclear Energy Nuclear energy comes from

the nucleus of atoms. There are two types of

nuclear energy, fusion & fission.

Fusion is nuclear energy that comes from joining atoms.

Fission is nuclear energy that comes from splitting atoms.

Currently the only nuclear energy that we use to make electricity is fission.

Nuclear Fission

Nuclear Fusion

The Manhattan Project

Top Secret project undertaken during World War II by American Scientists

Example of uncontrolled nuclear energy in the form of nuclear fission.

The first test bomb was exploded on July 16, 1945 near Alamogordo, New Mexico

Little Boy & Fat Man

Hiroshima

Destruction

Affect on People

Nagasaki

Thermonuclear Weapons