Nuclear power is not 100% clean, but it generates enormous amounts of energy while producing far less direct pollution than fossil fuels. This could be an important tool for reducing greenhouse gas emissions, although it carries major risks highlighted by the worst nuclear disasters of all time and leads to the creation of nuclear waste. One thing that makes it more dangerous is the strange blue light you often see in photos of nuclear reactors, and its source is fascinating.
This blue light is called Cherenkov radiation and results from protons and electrons (electrically charged particles) moving faster than light in water or other transparent substances. Objects generally can’t travel faster than the speed of light in a vacuum, but light actually travels about 25% slower in water, allowing charged particles to overtake it. This disrupts the water molecules and causes the release of photons, or particles of light, creating the blue glow that scientists liken to a sonic boom made of light rather than sound.
Cherenkov radiation, which appears blue to the human eye, is linked to the behavior of photons. They are electromagnetic particles, meaning they move in waves. The high frequency and short wavelengths of photons emitted by Cherenkov radiation make them appear blue or purple to our eyes.
What is Cherenkov radiation used for?
Cherenkov radiation is more than an aesthetic trick. It actually has various uses ranging from biomedical applications to nuclear policy enforcement. The International Atomic Energy Agency requires governments to provide access to and disclose information about their nuclear facilities, including their locations, quantities, and intended purposes. Using equipment that measures emitted light, the agency can determine the amount of Cherenkov radiation present in a body of water and compare it to the country’s reported use of spent nuclear fuel to verify compliance.
Cherenkov radiation is generated when patients undergo radiation therapy, a common cancer treatment. This means doctors can use it for medical imaging, allowing them to measure radiation levels in the body. Not only does this help manage dosing, but it also provides valuable information about the tumor that doctors can use to adjust care. Beyond this, Cherenkov radiation is also used for experiments in fields such as astrophysics and particle physics.
