strontium 9 definition by American Heritage Dictionary
nounThe American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The strontium isotope with mass 90, having a half-life of 28 years, used for its high-energy beta emission in certain nuclear electric power sources and constituting a radiation hazard in fallout.
strontium 9 - Science Definition
A radioactive isotope of strontium having a mass number of 90 and a half-life of 28 years. Strontium 90 is the most dangerous component of the fallout from nuclear explosions because it is easily absorbed by the body. It is also used in medicine to treat cancer.