Tiny bits of stuff can change.
They lose energy to do this.
This makes them turn into new things.
It can make heat.
This heat helps us in many ways.
Can you imagine tiny things changing?
Tiny bits of stuff can change.
They lose energy to do this.
This makes them turn into new things.
When a bit loses energy, it lets out small bits.
These bits are called radiation.
This change turns one kind of atom into another.
Some bits release a lot of heat.
This heat can help us do work.
Scientists look for bits that last a long time.
They also want bits that are easy to hide.
This keeps people safe from the radiation.
It is a very small but powerful change.
Tiny bits of matter can change. This change is called radioactive decay. It happens when an unstable nucleus loses energy. The nucleus lets out particles or radiation. This process turns one atom into another. We call the first atom the parent nuclide. The new atom is the daughter nuclide.
This change creates decay energy. This energy comes from a difference in mass. Scientists measure this energy in units called MeV. MeV stands for million electronvolts. This is a way to show how much power is there.
Some atoms release energy in different ways. They might use alpha decay or beta decay. Some also use gamma rays. People use this energy to make power. They use tools called RTGs. These tools need atoms with high decay energy. They also need a long half-life. A half-life is how long it takes for atoms to change.
Scientists look for atoms that do not emit strong gamma rays. This makes the tools lighter and cheaper. For example, Plutonium-238 is a good choice. It has a long half-life. Cobalt-60 is not good for this. It has a short five-year half-life. It also lets out strong gamma rays.
Decay energy is a special kind of energy change. It happens during a process called radioactive decay. This occurs when an unstable nucleus loses energy. The nucleus lets out radiation or tiny particles. This change turns one type of atom into another. We call the first atom the parent nuclide. The new atom is called the daughter nuclide.
This process works through a change in mass. The decay energy comes from a mass difference. We call this difference delta m. This mass difference equals the energy of the radiation. Scientists often write this energy difference as Q. They measure this energy in specific units. These units are MeV or thousand electronvolts.
Different atoms release energy in different ways. Some use alpha decay. Others use beta decay. In beta decay, energy splits between an electron and a neutrino. A neutrino is a particle emitted at the same time. Some atoms also release gamma rays. These rays are a type of radiation.
Scientists use these facts to make power tools. These tools are called radioisotope thermoelectric generators, or RTGs. A good RTG needs high decay energy. It also needs a long half-life. A half-life is how long it takes atoms to change. Plutonium-238 is a great choice for this. It has a long half-life of about eighty years.
Other atoms have different levels of power. Cobalt-60 is used for food irradiation. It has a radiation power of 17.9 W/g. However, its five-year half-life is too short for RTGs. It also releases strong gamma rays. This requires heavy shielding to stay safe. Other atoms like Polonium-210 have a power of 140 W/g. Strontium-90 has a power of 0.9 W/g.
Decay energy describes the energy change during radioactive decay. This process occurs when an unstable atomic nucleus loses energy. To stabilize itself, the nucleus emits ionizing particles or radiation. This transformation changes the original atom into a new type. Scientists call the starting atom the parent nuclide. The resulting atom is known as the daughter nuclide. This energy change is often represented by the symbol Q.
The mechanism of decay energy relies on a change in mass. The decay energy is equal to the mass difference between the parent and the daughter products. This mass difference is denoted as delta m. This difference in mass is converted directly into the energy of radiation, or E. Scientists measure this energy using specific units. These units are typically megaelectronvolts (MeV) or kiloelectronvolts (keV).
There are several distinct types of radioactive decay. In alpha decay, the nucleus releases an alpha particle. Beta decay is another common process. During beta decay, the energy is divided between an emitted electron and a neutrino. A neutrino is a tiny particle emitted at the same time as the electron. Some decays also release gamma rays. These are high-energy rays that carry away energy.
Scientists can calculate the radiation power, or P, of a substance. This calculation involves the radioactive activity, which is the number of transforming atoms per unit of time. It also uses the molar mass, or M, of the substance. The radiation power tells us how much energy is released over time. Different isotopes show very different levels of power. For example, Polonium-210 has a high radiation power of 140 W/g. In contrast, Radium-226 has a much lower power of only 0.02 W/g.
One specific example involves the isotope Cobalt-60. Cobalt-60 decays into Nickel-60. The mass difference in this process results in radiated energy of approximately 2.8 MeV. Cobalt-60 has a radiation power of 17.9 W/g. It also has a half-life, or the time for half the atoms to decay, of 5.27 years. This specific isotope is useful for food irradiation. However, it is not ideal for certain long-term power uses.
Engineers use decay energy to create radioisotope thermoelectric generators, or RTGs. These are devices that turn nuclear decay into electricity. For an RTG, scientists look for specific qualities. They want high decay energy combined with a long half-life. They also prefer sources that do not emit strong gamma radiation. This preference helps reduce the weight and cost of radiation shielding. Plutonium-238 is an excellent choice for RTGs. It has a long half-life of roughly eighty years and low gamma emissions.
Other isotopes have been used in RTGs with different results. Strontium-90 was used widely in the 20th century for remote locations. It is a high-yield product of nuclear fission. It is also easy to extract chemically from other fission products. However, Strontium-90 performs worse than Plutonium-238 on most measures. It has a shorter life and is a beta emitter. It also releases significant gamma radiation when its daughter nuclide decays. This makes it harder to shield than alpha emitters.
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