Gamma rays: Everything you need to know about these powerful packets of energy
International Conference on Nuclear Physics
Photons of light are massless particles that are essentially packets of energy. Because of a quantum-mechanical phenomenon known as wave-particle duality, particles can behave like waves, and photons are no different. Photons have wavelengths, and the amplitude of their wavelength determines where they sit on the electromagnetic spectrum. Radio and microwave photons sit at the lower energy, longer wavelength end of the spectrum, while in the shorter wavelength, higher-energy regime are photons of ultraviolet, X-rays and the most energetic of them all with the shortest wavelengths: gamma rays.
Gamma rays have wavelengths shorter than 10^-11 meters and frequencies above 30 x 10^18 hertz. The European Space Agency describes how gamma-ray photons have energies in excess of 100,000 electronvolts(opens in new tab) (eV). We can compare this to X-rays, which NASA describes as having energies between 100 eV and 100,000 eV(opens in new tab), and optical photons that we can see with our eyes, which are about 1 eV.
At the turn of the twentieth century, two forms of radiation emitted by decaying atoms were known, namely alpha particles (which are helium nuclei) and beta particles (which are electrons and positrons).
However, when the French chemist Paul Villard began experimenting with the radioactive element radium, which had been discovered two years prior by Marie and Pierre Curie, he noticed that the ionizing radiation produced by the decay of radium packed a harder punch than either alpha or beta particles.
This radiation received its name — gamma-rays — simply because gamma is the third letter in the Greek alphabet after alpha and beta. Unbeknownst to Villard and his cohorts in the early 1900s, the key difference between gamma rays and alpha/beta particles is that gamma rays are a form of light, whereas alpha and beta particles are made of matter.
To block gamma rays requires a dense material, and the thickness of that material depends on the substance. To reduce the strength of incoming gamma rays by a billion, you need 13.8 feet (4.2 meters) of water, 6.6 feet (2 m) of concrete or 1.3 feet (0.39 m) of lead, according to the radiation protection solution website StemRad.
This poses a problem for gamma-ray telescopes, such as NASA's Fermi Space Telescope. Ordinary telescopes like the Hubble Space Telescope use mirrors and lenses to collect and focus light, but gamma rays will simply pass straight through an ordinary telescope. Instead, gamma-ray telescopes have to employ other means.
On the Fermi Space Telescope, a gamma-ray photon will pass through a device called the Anti-coincidence Detector, which blocks cosmic rays that might give a false signal, according to NASA . The gamma-ray is then absorbed by one of 16 sheets of tungsten, a material that is dense enough to stop gamma rays.
By interacting with the tungsten, the gamma-ray is converted into an electron and a positron (the antimatter or antiparticle counterpart of an electron), the paths of which are read by a tracker, which is a module of silicon strips interweaved by tungsten foil that can determine the direction that the gamma-ray came from in space, based on the trajectory of the electron and the positron.
Finally, the electron and then positron have their energies measured by a calorimeter — a device that measures the energy of a particle by absorbing it — made from cesium iodide, and therefore the energy of the gamma-ray can be determined.
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#IonizingRadiation
#NuclearPhysics
#RadiationTherapy
#MedicalImaging
#RadioactiveDecay
#NuclearEnergy
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#GammaSpectroscopy
#NuclearMedicine
#RadiationDetection
#RadiationSafety
#Radioisotopes
#GammaRaySpectroscopy
#NuclearReactor
#RadiationExposure
#GammaDosimetry
#GammaIrradiation
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Gamma rays have wavelengths shorter than 10^-11 meters and frequencies above 30 x 10^18 hertz. The European Space Agency describes how gamma-ray photons have energies in excess of 100,000 electronvolts(opens in new tab) (eV). We can compare this to X-rays, which NASA describes as having energies between 100 eV and 100,000 eV(opens in new tab), and optical photons that we can see with our eyes, which are about 1 eV.
At the turn of the twentieth century, two forms of radiation emitted by decaying atoms were known, namely alpha particles (which are helium nuclei) and beta particles (which are electrons and positrons).
However, when the French chemist Paul Villard began experimenting with the radioactive element radium, which had been discovered two years prior by Marie and Pierre Curie, he noticed that the ionizing radiation produced by the decay of radium packed a harder punch than either alpha or beta particles.
This radiation received its name — gamma-rays — simply because gamma is the third letter in the Greek alphabet after alpha and beta. Unbeknownst to Villard and his cohorts in the early 1900s, the key difference between gamma rays and alpha/beta particles is that gamma rays are a form of light, whereas alpha and beta particles are made of matter.
To block gamma rays requires a dense material, and the thickness of that material depends on the substance. To reduce the strength of incoming gamma rays by a billion, you need 13.8 feet (4.2 meters) of water, 6.6 feet (2 m) of concrete or 1.3 feet (0.39 m) of lead, according to the radiation protection solution website StemRad.
This poses a problem for gamma-ray telescopes, such as NASA's Fermi Space Telescope. Ordinary telescopes like the Hubble Space Telescope use mirrors and lenses to collect and focus light, but gamma rays will simply pass straight through an ordinary telescope. Instead, gamma-ray telescopes have to employ other means.
On the Fermi Space Telescope, a gamma-ray photon will pass through a device called the Anti-coincidence Detector, which blocks cosmic rays that might give a false signal, according to NASA . The gamma-ray is then absorbed by one of 16 sheets of tungsten, a material that is dense enough to stop gamma rays.
By interacting with the tungsten, the gamma-ray is converted into an electron and a positron (the antimatter or antiparticle counterpart of an electron), the paths of which are read by a tracker, which is a module of silicon strips interweaved by tungsten foil that can determine the direction that the gamma-ray came from in space, based on the trajectory of the electron and the positron.
Finally, the electron and then positron have their energies measured by a calorimeter — a device that measures the energy of a particle by absorbing it — made from cesium iodide, and therefore the energy of the gamma-ray can be determined.
#GammaRadiation
#IonizingRadiation
#NuclearPhysics
#RadiationTherapy
#MedicalImaging
#RadioactiveDecay
#NuclearEnergy
#RadiationProtection
#GammaSpectroscopy
#NuclearMedicine
#RadiationDetection
#RadiationSafety
#Radioisotopes
#GammaRaySpectroscopy
#NuclearReactor
#RadiationExposure
#GammaDosimetry
#GammaIrradiation
#RadioactiveSources
https://nuclear-physics.sfconferences.com/
https://www.tumblr.com/settings/blog/nuclearconferences
https://www.instagram.com/aman__deep2023/
https://in.pinterest.com/nuclearconferences/_saved/
https://www.linkedin.com/in/aman-deep-aa1319268/
https://twitter.com/AmanDee71996637
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