what causes a radioactive isotope to stop decaying
Can the decay one-half-life of a radioactive material be changed?
Category: Physics Published: April 27, 2015
Public Domain Image, source: Christopher S. Baird.
Yes, the disuse one-half-life of a radioactive fabric tin can be changed. Radioactive decay happens when an unstable atomic nucleus spontaneously changes to a lower-energy state and spits out a scrap of radiations. This process changes the atom to a dissimilar chemical element or a different isotope. Since radioactive decay is a spontaneous outcome, you may recall that the half-life of the decay process is completely stock-still and cannot be contradistinct by outside influences. However, this argument is not completely true.
First of all, information technology is worth pointing out that the time when an individual radioactive atom decays is completely random. It is incommunicable to predict when an individual radioactive atom will disuse. The half-life of a sure blazon of atom does not draw the exact amount of time that every unmarried cantlet experiences before decaying. Rather, the half-life describes the average amount of fourth dimension it takes for a large group of amounts to attain the point where half of the atoms take rust-covered.
The half-life of a radioactive cloth can be changed using time dilation effects. Co-ordinate to relativity, fourth dimension itself can exist slowed down. Everything that experiences time tin therefore exist given a longer constructive lifetime if time is dilated. This can be done in 2 ways. Traveling at a speed close to the speed of light causes fourth dimension to slow downwards significantly, relative to the stationary observer. For instance, a number of radioactive atoms shot through a tube at high speed in the lab will have their one-half-life lengthened relative to the lab considering of time dilation. This result has been verified many times using particle accelerators. Time can also be dilated by applying a very strong gravitational field. For instance, placing a agglomeration of radioactive atoms nigh a black hole will also extend their one-half-life relative to the distant observer considering of time dilation.
The one-half-life of radioactive decay can also be altered by changing the state of the electrons surrounding the nucleus. In a type of radioactive disuse called "electron capture", the nucleus absorbs one of the atom's electrons and combines it with a proton to make a neutron and a neutrino. The more the wavefunctions of the atom's electrons overlap with the nucleus, the more than able the nucleus is to capture an electron. Therefore, the half-life of an electron-capture radioactive disuse mode depends slightly on what land the atom's electrons are in. By heady or deforming the cantlet'south electrons into states that overlap less with the nucleus, the half-life tin be reduced. Since the chemical bonding between atoms involves the deformation of diminutive electron wavefunctions, the radioactive half-life of an cantlet can depend on how information technology is bonded to other atoms. Merely by changing the neighboring atoms that are bonded to a radioactive isotope, we can change its one-half-life. However, the change in half-life achieved in this way is typically small. For instance, a study performed past B. Wang et al and published in the European Physical Journal A was able to measure out that the electron capture one-half-life of glucinium-vii was made 0.9% longer by surrounding the beryllium atoms with palladium atoms.
In addition to altering the chemical bonds, the one-half-life can be altered by only removing electrons from the atom. In the extreme limit of this approach, all of the electrons can be ripped off of a radioactive atom. For such an ion, there are no longer any electrons available to capture, and therefore the half-life of the electron capture radioactive decay mode becomes infinite. Certain radioactive isotopes that can only decay via the electron capture mode (such as rubidium-83) can be made to never decay by ripping off all the electrons. Other types of radioactive decay besides electron capture have also been found to accept the disuse half-life depend on the country of the surrounding electrons, but the effects are smaller. The alter in half-life due to changing the electron surround is generally very minor, typically much less than 1%.
Lastly, the half-life of a radioactive cloth tin be changed past bombarding it with high-energy radiation. This should not come as a surprise since radioactive disuse is a nuclear reaction, and inducing other nuclear reactions at the same fourth dimension as the disuse tin interfere with it. Even so, at this point, y'all don't really have stand-alone radioactive decay. Rather, you have nuclear reaction soup, so this arroyo may not really count equally "irresolute the one-half-life".
When reference books list values for the half-life of various materials, they are really listing the half-life for the material when its atoms are at balance, in the ground state, and in a detail chemical bonding configuration. Annotation that most changes to the half-life of radioactive materials are very small-scale. Furthermore, large changes to a half-life crave elaborate, expensive, high-energy equipment (e.k. particle accelerators, nuclear reactors, ion traps). Therefore, exterior of specialized labs, we tin can say that equally a good approximation radioactive decay half-lives don't change. For instance, carbon dating and geological radiometric dating are so accurate because disuse one-half-lives in nature are and so close to constant.
Source: https://wtamu.edu/~cbaird/sq/2015/04/27/can-the-decay-half-life-of-a-radioactive-material-be-changed/
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