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The so-called long-duration gamma-ray bursts produce a total energy output of about 10 44 joules (as much energy as the Sun will produce in its entire life-time) but in a period of only 20 to 40 seconds. Gamma rays are approximately 50% of the total energy output.
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 ...
A few gamma-ray bursts have shown evidence for an additional, delayed emission component at very high energies (GeV and higher). One theory for this emission invokes inverse Compton scattering . If a GRB progenitor, such as a Wolf-Rayet star , were to explode within a stellar cluster , the resulting shock wave could generate gamma-rays by ...
The means by which gamma-ray bursts convert energy into radiation remains poorly understood, and as of 2010 there was still no generally accepted model for how this process occurs. [132] Any successful model of GRB emission must explain the physical process for generating gamma-ray emission that matches the observed diversity of light curves ...
Gamma radiation detected in an isopropanol cloud chamber. Gamma (γ) radiation consists of photons with a wavelength less than 3 × 10 −11 m (greater than 10 19 Hz and 41.4 keV). [4] Gamma radiation emission is a nuclear process that occurs to rid an unstable nucleus of excess energy after most nuclear reactions. Both alpha and beta particles ...
If the lost recoil energy is small compared with the energy linewidth of the nuclear transition, then the gamma-ray energy still corresponds to the energy of the nuclear transition and the gamma ray can be absorbed by a second atom of the same type as the first. This emission and subsequent absorption is called resonant fluorescence. Additional ...
Most of the radiolytic activity occurs in the core of the reactor where the neutron flux is highest; the bulk of energy is deposited in water from fast neutrons and gamma radiation, the contribution of thermal neutrons is much lower. In air-free water, the concentration of hydrogen, oxygen, and hydrogen peroxide reaches steady state at about ...
Since scattering increases the distance travelled by photons within tissue, the probability of photon absorption also increases. Because scattering has weak dependence on wavelength, the NIR window is primarily limited by the light absorption of blood at short wavelengths and water at long wavelengths. The technique using this window is called ...