by What are Alpha Emitters?
Alpha emitters are a type of radioactive substance that emits alpha particles as they undergo radioactive decay. Alpha particles are essentially two protons and two neutrons bound together, which is the same as the nucleus of a helium atom. Only the heaviest elements such as uranium and plutonium are capable of emitting alpha particles.
How Alpha Decay Works
In alpha decay, Alpha emitters parent nucleus ejects an alpha particle to transform itself into a new nuclide. Because an alpha particle has two protons and two neutrons, alpha decay reduces the atomic number by two and the atomic mass by four. The energy released in this type of radioactive decay allows the parental nucleus to lower its total binding energy by transforming into a more stabile daughter nuclide.
For example, uranium-238 decays into thorium-234 by emitting an alpha particle through the following nuclear equation:
238U → 234Th + 4He
In this process, uranium-238 loses two protons and two neutrons to become thorium-234 while releasing an alpha particle, which is a helium-4 nucleus. The energy released in this transformation is about 4.2 MeV.
Energy and Penetration of Alpha Particles
Although alpha particles carry a large amount of energy, between 3 to 9 MeV, they have little penetrating power and can be stopped by a few centimeters of air or by skin. This is because alpha particles interact readily with other matter due to their relatively large mass and electrical charge. Only the outer layers of dead skin are needed to stop alpha radiation.
If alpha-emitting atoms are ingested or inhaled, however, the radiation poses significant dangers since the radioactive sources would be internalized close to living tissue. Inside the body, alpha particles can damage nearby living cells and disrupt biological processes by breaking chemical bonds in important molecules like DNA.
Health Effects of Internal +Emitters
Internal exposure to alpha emitters carries the highest cancer risks compared to other types of radiation. DNA damage caused by alpha particles emitted in close proximity to cells is much more difficult for the body to repair compared to damage from beta and gamma radiation. If left unrepaired, DNA mutations can lead to the development of cancer over time.
Studies on uranium miners who inhaled radon decay products, mainly polonium-218 and polonium-214, provide clear evidence of increased lung cancer risks. Autopsy results of these miners showed cellular changes in bronchial tissues, including increased mitosis and metaplasia, from accumulated alpha radiation exposure inside the lungs over many years of underground work.
Another infamous example is heavy metal radium, which was once used to paint watch and clock dials but later proved to cause fatal radium-induced jaw cancer in numerous young women who licked their paintbrush tips to create a fine point. Absorbed internally, a small quantity of a few nanocuries of an alpha emitter like radium-226 can potentially cause cancer.
Uses and Controls
Despite their high toxicity, some emitters continue to be used in applications where external exposure risks are negligible. Smoke detectors contain a small amount of americium-241, an alpha emitter that ionizes air to detect smoke particles. Satellites powered by thermoelectric generators use the heat released from plutonium-238’s radioactive decay. These radioactive sources are carefully contained and regulated.
Even low levels of exposure require strict controls, however. The international consensus is that no level of internal alpha radiation exposure can be considered safe. The radiobiological effectiveness of alpha particles makes internal contamination a serious health concern even at sub-curie quantities. Regulatory limits for permissible internal deposition of alpha emitters into the body are set much lower than for other types of nuclear radiation to account for their high cancer risks.
Proper handling, containment, decontamination, and disposal are therefore required to minimize risks when using alpha-emitting materials in industrial or research applications. Radioactive waste from mining, fuel cycle, medical, and other nuclear activities also needs careful long-term management to isolate these persistent alpha-emitting radionuclides from the environment and human contact for many centuries until they completely decay.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
Money Singh is a seasoned content writer with over four years of experience in the market research sector. Her expertise spans various industries, including food and beverages, biotechnology, chemical and materials, defense and aerospace, consumer goods, etc.
