radioactive nuclide

Copper-64 is a radioactive nuclide of copper which has unique decay properties making it useful in nuclear medicine for both imaging and therapy.

Decay constant: the fraction of a number of atoms of a radioactive nuclide that disintegrates in a unit of time.

For example, carbon-14, a radioactive nuclide with a half-life of only 5730 years, is constantly produced in Earth's upper atmosphere due to interactions between cosmic rays and nitrogen.

The Prosecutor General's Office did not disclose his condition except to say in a statement that he had "an illness also connected to poisoning by a radioactive nuclide."

A biological half-life or elimination half-life is the time it takes for a substance (drug, radioactive nuclide, or other) to lose one-half of its pharmacologic, physiologic, or radiological activity.

He then produced more conclusive proof by shooting gamma rays produced by the natural radioactive nuclide ThC (Tl) into other materials, resulting in the creation of positron-electron pairs.

In these cases, usually the half-life of interest in radiometric dating is the longest one in the chain, which is the rate-limiting factor in the ultimate transformation of the radioactive nuclide into its stable daughter.

In contrast, the radioactive nuclide beryllium-7 falls into this light element range, but this nuclide has a half-life too short for it to have been formed before the formation of the solar system, so that it cannot be a primordial nuclide.

While the moment in time at which a particular nucleus decays is unpredictable, a collection of atoms of a radioactive nuclide decays exponentially at a rate described by a parameter known as the half-life, usually given in units of years when discussing dating techniques.

"As the result of the check it was established that Mr. Litvinenko died as the result of poisoning by a radioactive nuclide and Mr. Kovtun, who met with Mr. Litvinenko in London, has an illness also connected to poisoning by a radioactive nuclide."