Troposphere: The weather portion of the atmosphere, from sea level to about forty thousand feet.
Tropospheric fallout: World-wide fallout, mainly from small bombs (less than a megaton) whose clouds remain in the troposphere. This fallout occurs on the average two weeks to a month after the explosion and stays in a latitude close to the latitude of the explosion.
Uranium: Element with charge 92. Natural uranium contains 1 part of U²³⁵ to 139 parts of U²³⁸. U²³⁵ is a fissionable material and U²³⁸ can be converted to plutonium, which is fissionable.
X-ray: Penetrating electromagnetic radiation, usually made by bombarding a metal target with energetic electrons. X-rays and gamma rays are really the same thing.
FOOTNOTES
[1]The word “noble” is perhaps a misnomer—these atoms do not even seek the company of each other.
[2]Quotes are put around the word atom because, having lost one of its electrons, it is no longer an ordinary neutral atom in its ground state.
[3]Yet.
[4]Actually the same state may be occupied by two neutrons and two protons. The reason is that neutrons and protons are magnetic particles with a north and a south pole. Consequently the demand for a difference can be satisfied by having one neutron (or proton) with its north pole pointing up and another with its north pole pointing down.
[5]It seems that neutrinos emitted in the company of electrons have the symmetry of a right screw; those emitted together with a positron have the symmetry of a left screw.