We have learned about the type of transmutation that deals with the changing of the number of protons in the nucleus of atoms, subsequently changing the identity of the atom altogether. Along with that type of transmutation, there is also neutronic transmutation, or a type of transmutation dealing with the changing of the number of neutrons in the nucleus of atoms. This second type of transmutation does not change the identity of the atom to the degree of protonic transmutation, but rather changes the properties of the element that it is enacted on.
A common type of protonic transmutation is caused by the radioactive decay of an atom when electrons are emitted as beta particles. This and the accepting of a neutron into the nucleus of atom are both depicted in this diagram below, one after another, with the neutronic transmutation happening first.
The first part of this reaction sequence is the acceptance of the neutron into the nucleus of the I-129 atoms, changing it into I-130. This step is very important to the radioactive decay reaction because the differing properties of I-129 and I-130. I-129 has a half-life of 15.7 million years and the only circumstance that we have seen the decay of I-129 is in meteorites that date back to the creation of the solar system when Xe-129 is found in them. I-130, on the other hand, is a beta-emitting isotope with a half-life of eight days. It’s crazy to think that one neutron would have such an effect on the radioactive decay of an atom without changing its identification as an element. Additionally, the second part of the reaction in the graphic above would take forever to happen with I-129, but, when I-130 is used instead, much faster results will appear.
The second sequence in the reaction is the protonic transmutation which consists of I-130 atoms emitting beta particles. This not only changes the properties of the atoms, but changes their elemental identification as well. The I-130 loses an electron through beta particle emission and, as a result, changes a neutron into a proton. Once this has happened, the atom is no longer I-130, but Xe-130. This transformation is one similar to what alchemists of old were after, only not with gold as the result…
These two reactions types are used today in many different ways. Protonic transmutation is used in doping silicon so that it can be used as a semiconductor in electric appliances. In the transmutation reaction for the silicon, the thermal neutron is captured by the Si-30 atom. Due to the high neutron-proton ratio of Si-31, it will release a beta and, by converting a neutron to a proton, transmute to a P-31 atom. Neutronic transmutation is used in the production of Molybdenum-99, an isotope that beta decays into Technetium-99, a widely used medical diagnostic radioisotope. Radioisotopes like Molybdenum-99 are produced in reactors by exposing suitable target materials to the intense reactor neutron flux for an appropriate time. Target materials to be irradiated are sealed in capsules, loaded in simple assemblies and lowered into predetermined core locations for irradiation. Afterwards, the irradiated targets are loaded in appropriate shielding containers and transported to hot chemistry labs for processing.
So Brad, just as a clarification, the protronic transmutation occurs after a neutron has been accepted and then the electron is being released causing the neutron to shift into a proton, if so how does this work is there any other information you can provide?
ReplyDeleteYea, in the example above, the protonic transmutation occurs because the neutronic transmutation is turning the atom into a radioisotope which then undergoes beta decay causing the loss of an electron which triggers this weird thing that turns a neutron into a proton (not really sure how that happens exactly but it does). That's basically it.
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