How is radioactivity made?
Answer:
Radioactivity refers to the particles which are emitted from nuclei as a result of nuclear instability. Because the nucleus experiences the intense conflict between the two strongest forces in nature, it should not be surprising that there are many nuclear isotopes which are unstable and emit some kind of radiation. The most common types of radiation are called alpha, beta, and gamma radiation, but there are several other varieties of radioactive decay.
Radioactive decay rates are normally stated in terms of their half-lives, and the half-life of a given nuclear species is related to its radiation risk. The different types of radioactivity lead to different decay paths which transmute the nuclei into other chemical elements. Examining the amounts of the decay products makes possible radioactive dating.
Radiation from nuclear sources is distributed equally in all directions, obeying the inverse square law.
Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. This decay, or loss of energy, results in an atom of one type, called the parent nuclide transforming to an atom of a different type, called the daughter nuclide. For example: a carbon-14 atom (the "parent") emits radiation and transforms to a nitrogen-14 atom (the "daughter.") This is a random process on the atomic level, in that it is impossible to predict when a particular atom will decay, but given a large number of similar atoms, the decay rate, on average, is predictable.
Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. This decay, or loss of energy, results in an atom of one type, called the parent nuclide transforming to an atom of a different type, called the daughter nuclide. For example: a carbon-14 atom (the "parent") emits radiation and transforms to a nitrogen-14 atom (the "daughter.") This is a random process on the atomic level, in that it is impossible to predict when a particular atom will decay, but given a large number of similar atoms, the decay rate, on average, is predictable.
The trefoil symbol is used to indicate radioactive material.The SI unit of radioactive decay is the becquerel (Bq). One Bq is defined as one transformation (or decay) per second. Since any reasonably-sized sample of radioactive material contains many atoms, a Bq is a tiny measure of activity; amounts on the order of TBq (terabecquerels) or GBq (gigabecquerels) are commonly used. Another unit of decay is the curie, which was originally defined as the radioactivity of one gram of pure radium, and is equal to 3.7 × 10^10 Bq.
Explanation
The neutrons and protons that constitute nuclei, as well as other particles that may approach them, are governed by several interactions. The strong nuclear force, not observed at the familiar macroscopic scale, is the most powerful force over subatomic distances. The electrostatic force is also significant. Of lesser importance is the weak nuclear force.
The interplay of these forces is very complex. Some configurations of the particles in a nucleus have the property that, should they shift ever so slightly, the particles could fall into a lower-energy arrangement (with the extra energy moving elsewhere). One might draw an analogy with a snowfield on a mountain: while friction between the snow crystals can support the snow's weight, the system is inherently unstable with regards to a lower-potential-energy state, and a disturbance may facilitate the path to a greater entropy state (i.e., towards the ground state where heat will be produced, and thus total energy is distributed over a larger number of quantum states). Thus, an avalanche results. The total energy does not change in this process, but because of entropy effects, avalanches only happen in one direction, and the end of this direction, which is dictated by the largest number of chance-mediated ways to distribute available energy, is what we commonly refer to as the "ground state."
Such a collapse (a decay event) requires a specific activation energy. In the case of a snow avalanche, this energy classically comes as a disturbance from outside the system, although such disturbances can be arbitrarily small. In the case of an excited atomic nucleus, the arbitrarily small disturbance comes from quantum vacuum fluctuations. A nucleus (or any excited system in quantum mechanics) is unstable, and can thus spontaneously stabilize to a less-excited system. This process is driven by entropy considerations: the energy does not change, but at the end of the process, the total energy is more diffused in spacial volume. The resulting transformation alters the structure of the nucleus. Such a reaction is thus a nuclear reaction, in contrast to chemical reactions, which also are driven by entropy, but which involve changes in the arrangement of the outer electrons of atoms, rather than their nuclei.
Some nuclear reactions do involve external sources of energy, in the form of collisions with outside particles. However, these are not considered decay. Rather, they are examples of induced nuclear reactions. Nuclear fission and fusion are common types of induced nuclear reactions.
Radioactivity is the spontaneous disintegration of atomic nuclei. The nucleus emits particles, ß particles, or electromagnetic rays during this process.
Alpha () Decay:
Alpha decay occurs when the nucleus spontaneously ejects an particle. An particle is really 2 protons and 2 neutrons, or an He nucleus. So when an atom undergoes decay, its atomic number decreases by 2 and its atomic mass decreases by 4. particles do not penetrate much material, for they can be stopped by paper. An example of decay is the following:
Pu239 U235 + particle (He-4 nucleus)
You should really do more research and then ask more specific questions at that point. This is a complicated topic but I'll give you some starting points for research.
I'll give you only the bare basics... I am ignoring fusion here since we really don't do that on Earth yet, and i am not well informed on fusion in general.
Induced reactions are caused by outside forces or processes.
Spontaneous reactions only occur in unstable nuclei, that are naturally moving to a stable,(equilibrium), state, as all things seek equilibrium.
Spontaneous reactions move along the line of stability, you need to google that, the line of stability is way too complicated to explain here.
Induced reactions occur then the resultant fission products follow the rules of spontaneous reactions.
There are 4 types of nuclear disintegrations,(radiation), being alpha, beta, gamma, and nuetron.
Keep in mind this is a basic, high level overview.
Gamma emits a high energy photon and has infinite range and is subject to the inverse square law. Beta, basically/primarily is the release of a high energy electron, and an antinuetrino. Beta is related to the weak nuclear force also known as the electroweak force. Beta can be blocked by things like clothing . Alpha is basically the emission of a helium atom. Alpha being a large particle is blocked by skin.
Gamma is by far the most worrisome exposure to man, as it penetrates deeply even at significant differences. Beta and Alpha are also problems. They are modtly blocked by common materials, but depending on the flux your exposure can go from almost none to dangerous levels. [Flux is a measure of the amount of particles that pass a given point in a given interval.] This is due to the uncertainty principle, basically the more/higher the flux the more particles penetrate your body to do damage.
Nuetron radiation is some what a different beast. Nuetrons are emitted as heavy atoms/elements as larger elements/atoms split or fission and become lighter atoms. They emit nuetrons in the process. The nuetrons cause damage, and they can be harnessed to generate a self-sustaining nuclear reaction under the right circumstances. Nuetrons are the largest type of emitted radiation, except for alphas. Therefore they cause a great deal of damage to people through DNA interactions, and they damage materials such as stell by knocking atoms or molecules out of place hence weakening the materials. This weakening of materials, steel and concrete, is the limiting factor in how long a nuclear reactor can safely operate. It is called nuetron embrittlement and the safe life of a reactor follows the brittle fracture pressure limit curve.
Resdiual/environmental radiation is a huge issue becasue you are exposed to it daily, building up your total received dose. Also you can eat, inhale, absorb through your skin, etc. radioactive particles, which then decay inside your body and expose you to further doses, at closer ranges to your organs, bone marrow etc...
All that being said, look up the line of stability because that will explain the specific how and why of the different types of radiation, (decay). It would take pages here to cover that.
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