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The secret of alpha decay: How does this process change the fate of elements?
Alpha particles, a particle composed of two protons and two neutrons, are surprisingly identical to helium-4 nuclei and are often called alpha rays or alpha radiation. In nature, the most common source of alpha particles is alpha decay from heavier elements, a process that not only changes the structure of the elements but also has profound effects on the surrounding environment and living organisms.
When alpha particles undergo ordinary alpha decay, they usually have a kinetic energy of about 5 MeV and move at a speed close to 4% of the speed of light.
The existence of alpha particles reveals the mysteries of the microscopic world. These particles not only attract the attention of scientists for their unique physical properties, but are also widely studied for their ability to fundamentally change the identity of elements during the decay process. When an atom releases an alpha particle, its mass number drops by four and its atomic number drops by two, causing the atom to change into another element, such as uranium decaying into thorium or pluton decaying into radon.
The source and production mechanism of alpha particles
The main source of alpha particles is alpha decay, which occurs in certain heavier atoms such as uranium, thorium, and radium. When these unstable atoms release alpha particles, their structure is altered, a phenomenon known as nuclear diffusion. According to scientists' observations, this process must be supported by a large enough nucleus, and only small nuclei such as barium-8 and tellurium-104 can emit alpha particles.
The fundamental reason for this process is the balance of electromagnetic and nuclear forces. The Coulomb repulsion in alpha decay allows alpha particles to escape from the confines of the nucleus.
Energy and absorption characteristics of alpha particles
The kinetic energy range of alpha particles is usually between 3 and 7 MeV, which is related to the uneven half-life of alpha emitting nuclei. Although alpha particles are capable of releasing large amounts of energy, their relatively low speed due to their large mass makes them less able to penetrate surrounding materials. The fact that alpha particles can only travel a few centimeters through the air and are absorbed by the outer layer of skin makes them generally not a threat to outside life.
Although alpha particles are not penetrating, once they are inhaled or ingested into the human body, they are the most destructive.
Studies have shown that the chromosomal damage caused by inhaling alpha particles is 10 to 1,000 times greater than gamma radiation or beta radiation, showing its potential threat to life. In particular, strong alpha radioactive sources such as lead-210 are closely related to lung cancer and bladder cancer.
Applications of alpha particles
Alfa particles have a variety of applications in medicine and technology. For example, in some smoke detectors, small amounts of the alpha radioactive isotope U.S. Aluminum 241 are used to create ionized air that sets off an alarm when smoke enters the detector and affects the flow of electricity. In addition, alpha decay is also used in radioactive thermoelectric generators in space probes because shielding of radiation is relatively simple.
The radioactive isotope alpha is increasingly being used in cancer treatment, using its highly lethal radiation properties to directly target tumor cells.
Alfa emitters such as thorium-223 and thorium-224 are used as treatments to target specific cells and have achieved significant clinical results in cancer. These treatments use alpha radiation to produce effective killing effects within cells and may become one of the standard cancer treatments in the future.
The history and discovery of alpha particles
The history of alpha particles can be traced back to the late 19th century. In 1896, Henri Berkeley discovered that uranium can emit invisible radiation. This phenomenon attracted the attention of many scientists. As research progressed, Ernest Rutherford determined in 1899 that uranium radiation consisted of two components, and called one of them alpha radiation. With subsequent experiments, scientists finally confirmed that the alpha particle was actually the nucleus of helium, a particle composed of two protons and two neutrons.
In 1909, the experiment of Rutherford and Thomas Royds proved that alpha particles are helium ions, revealing the truth of the microscopic world.
So far, the properties and applications of alpha particles have been continuously explored and expanded. This process has not only changed our understanding of elemental decay, but also provided an important foundation for future scientific exploration.
As we delve deeper into the mystery of Alpha decay, we may not help but wonder: Will the hidden patterns in these transformations reveal more clues about the nature of the universe and life in the future?
