Gamma rays penetrate (pass through) matter much more easily than other forms of radiation.[3] In fact, gamma rays are even more penetrating thanX-rays.[4] This makes them both useful and dangerous. Gamma rays are carefully used to treat certain cancers or other health conditions. They also have a role in food safety and studyingouter space.
By 1900, physicistErnest Rutherford coined the term "gamma rays". "Gamma" is the third letter of theGreek alphabet. Rutherford identified three types of radiation that are produced by radioactive decay. He named the three types alpha, beta, and gamma radiation. He put them in order from least to most penetrating power. Because gamma rays can pass through matter much more easily than the other forms of radiation, he listed it third.
In 1903,Ernest Rutherford named this radiation "gamma rays" because they were the third type of radiation he discovered (after alpha and beta rays). ("Gamma" is the third letter of the Greek alphabet.) He they strongly penetratedmatter.
By 1900, Rutherford had already named two less penetrating types of decay radiation (discovered byHenri Becquerel):alpha rays andbeta rays (in the order of penetrating power). Gamma rays pass through matter much more easily than alpha or beta rays do.
Unlike alpha and beta rays, gamma rays easily pass through the body (and other objects). This makes it difficult to protect people from this type of radiation. Shielding made from lead or concrete is required.
On Earth, themagnetosphere protects life from most types of lethalcosmic radiation - but not gamma rays.
Gamma radiation is often used to kill living things, in a process called irradiation. For example, irradiation is used to remove decay-causingbacteria from many foods, and to preventfruits andvegetables from sprouting in order to maintain their freshness or flavor.
Even though gamma rays can causecancer, they also kill cancercells. For this reason, gamma rays are used to treat some types of cancer.
A procedure called gamma-knife radiosurgery can be used to kill cancer cells. This is not an actualsurgery. The procedure is
Instead, the procedure directs highly focused beams of gamma rays towards atumor in thebrain or upperspine.[5] This concentrates the radiation on the tumor while also minimizing damage to the bodytissues around it.
This is especially helpful if a tumor is in a location that doctors can't reach using traditional surgery.[5] Gamma-knife surgery can also be used alongside traditional surgery to prevent a tumor from growing.[5]
Nuclear medicine uses gamma rays in imaging techniques (likePET scans) in order to diagnose problems.[7] They can also be used to sterilize medical equipment.[8]
Gamma-ray bursts [inouter space] are the most energetic and [brightest] electromagnetic events since theBig Bang and can release more energy in 10 seconds thanour Sun will emit in its entire 10-billion-year expected lifetime! Gamma-rayastronomy presents unique opportunities to explore these exotic objects. By exploring theuniverse at these high energies,scientists can search for newphysics, testingtheories and performingexperiments that are not possible inEarth-boundlaboratories.
