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It has a half-life of 30 years, and decays by beta decay without gamma ray emission to a metastable state of barium-137 (137m Ba). Barium-137m has a half-life of a 2.6 minutes and is responsible for all of the gamma ray emission in this decay sequence. The ground state of barium-137 is stable. The photon energy (energy of a single gamma ray) of ...
For example, gamma rays that require 1 cm (0.4 inch) of lead to reduce their intensity by 50% will also have their intensity reduced in half by 4.1 cm of granite rock, 6 cm (2.5 inches) of concrete, or 9 cm (3.5 inches) of packed soil. However, the mass of this much concrete or soil is only 20–30% greater than that of lead with the same ...
The gamma rays emitted from radium 226, accounting for 4% of the radiation, are harmful to humans with sufficient exposure. Gamma rays are highly penetrating and some can pass through metals, so Geiger counters or a scintillation probe are used to measure gamma ray exposures when monitoring for NORM.
A gamma ray burst (GRB) is the most powerful form of explosion in the known universe.They are produced when massive stars die, right before they turn into black holes, and were originally ...
Artist's conception of gamma-ray flash and related phenomena. The red dots show some of the ~500 terrestrial gamma-ray flashes daily detected by the Fermi Gamma-ray Space Telescope through 2010. A terrestrial gamma-ray flash (TGF), also known as dark lightning, is a burst of gamma rays produced in Earth's atmosphere.
Significant gamma-ray emission from our galaxy was first detected in 1967 [9] by the detector aboard the OSO 3 satellite. It detected 621 events attributable to cosmic gamma rays. However, the field of gamma-ray astronomy took great leaps forward with the SAS-2 (1972) and the Cos-B (1975–1982) satellites. These two satellites provided an ...
The incoming gamma ray effectively knocks one or more neutrons, protons, or an alpha particle out of the nucleus. [1] The reactions are called (γ,n), (γ,p), and (γ,α), respectively. Photodisintegration is endothermic (energy absorbing) for atomic nuclei lighter than iron and sometimes exothermic (energy releasing) for atomic nuclei heavier ...
Either a long-duration burst in which the presence of a bright supernova is ruled out, or a short-duration burst with extremely long-lasting gamma-ray emission. GRB 080319B: z = 0.937: Swift: The most (optically) luminous event of any nature observed in the universe to date. By far the brightest optical afterglow of any gamma-ray burst. GRB 080916C