Isotopes of sodium


There are 21 recognized isotopes of sodium, ranging from to and two isomers. is the only stable isotope. It is considered a monoisotopic element and it has a standard atomic weight of. Sodium has two radioactive cosmogenic isotopes. With the exception of those two, all other isotopes have half-lives under a minute, most under a second. The shortest-lived is, with a half-life of seconds.
Acute neutron radiation exposure converts some of the stable in human blood plasma to. By measuring the concentration of this isotope, the neutron radiation dosage to the victim can be computed.
is a positron-emitting isotope with a remarkably long half-life. It is used to create test-objects and point-sources for positron emission tomography.

List of isotopes

Sodium-22

Sodium-22 is a radioactive isotope of sodium, undergoing positron emission to with a half-life of 2.605 years. is being investigated as an efficient generator of "cold positrons" to produce muons for catalyzing fusion of deuterium. It is also commonly used as a positron source in positron annihilation spectroscopy.

Sodium-24

Sodium-24 is one of the most important isotopes. It is radioactive and created from common sodium-23 by neutron bombardment. With a 15-hour half-life, decays to by emission of an electron and two gamma rays. Exposure of the human body to intense neutron flux creates in blood plasma. Measurements of its quantity are used to determine the absorbed radiation dose of the patient. This is used to determine the level of medical treatment required.
When the sodium-potassium alloy is used as a coolant in nuclear reactors, is created, which makes the coolant radioactive. When the decays, it causes a buildup of magnesium in the coolant. Since the half life is short, the portion of the coolant ceases to be radioactive within a few days after removal from the reactor.