Scientists have synthesized a type of glass that can repair itself after being damaged by gamma rays.
The researchers observed that films of chalcogenide glass with gamma-ray-induced defects gradually healed over time at room temperature, returning to a state of structural integrity without any other intervention.
The discovery, led by engineer Myung Kang from Alfred University in the US, reveals a material that could be truly useful in the space environment, where gamma rays are constantly streaming, and in places like radioactive facilities, where radiation-resistant sensors can make a big difference.
“More and more people are turning to glasses, which have optical transparency similar to crystals such as germanium, but whose composition and properties can be engineered for the applications in which germanium is used.” Physicist Kathleen Richardson says: of University of Central Florida.
“These glasses are increasingly being used in community systems looking for alternatives to the crystalline solutions that have been used historically.”
Glass may seem like a rather strange material at first glance, but it is extremely useful in many ways. Chalcogenide Glass Elements including sulfur, selenium, tellurium and polonium interact with light, making them useful in optical devices, particularly in the field of infrared sensing.
Using very precise mixtures of sulfur, germanium and antimony, Kang and his colleagues had produced just such glass for use in satellite circuitry.
“These glasses are specific to infrared because they block oxygen.” Richardson says“They’re made of elements that are on the far right side of the periodic table. When they combine together, they create a material that has very large atoms and weak bonds, and is very transparent to infrared light.”
These glasses need to be tested under the stresses they may be exposed to under operating conditions, and in the space environment, one of those stresses is gamma radiation.
At the Earth’s surface, we are not exposed to cosmic gamma rays because our atmosphere acts as a very effective shield, but gamma rays can be produced by the radioactive decay of certain elemental isotopes.
To expose the samples to high-energy light, the researchers Cobalt 60It’s a compound made from radioactive cobalt. This exposure distorted the weak bonds between the atoms, causing microscopic defects in the glass.
The glass was then placed in a room temperature environment. After 30 days, the glass had recovered.
“Because the atoms are large and the bonds are weak, over time these bonds can loosen and reform from their distorted arrangement, allowing them to heal.” Richardson says.
“The concept of self-healing glass is that when an experiment is exposed to high-energy radiation, these bonds become distorted or broken. Over time, just at room temperature, these bonds repair themselves, allowing the structure to reform on its own.”
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This possibility is very intriguing: this glass, or future forms of it, could find future use, for example, as a durable, reversible radiation sensor for extreme environments.
The researchers hope to develop this glass further and use it as a stepping stone to develop other glasses with the same self-healing abilities.
“Going forward, my new research group aims to develop novel irradiation-induced ceramics and in situ microstructural and optical metrology methods to realize an ultrafast, lightweight optical platform.” Kang says.
“My research, under the unifying theme of the effects of radiation on chalcogenide ceramics, has produced highly influential results.”
This study Materials Research Association Bulletin.
