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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). Photodisintegration is endothermic (energy absorbing) for atomic nuclei lighter than iron and sometimes exothermic (energy releasing) for atomic nuclei heavier than iron .
Iodine-123 (123 I) is a radioactive isotope of iodine used in nuclear medicine imaging, including single-photon emission computed tomography (SPECT) or SPECT/CT exams. The isotope's half-life is 13.2232 hours; [1] the decay by electron capture to tellurium-123 emits gamma radiation with a predominant energy of 159 keV (this is the gamma primarily used for imaging).
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 ...
The germanium isotope emits two weak gamma rays and a conversion electron. 73 31 Ga → 73m2 32 Ge + 2 γ + e − ; 73m2 32 Ge → 73 32 Ge + + γ (53.4 keV) + γ (13.3 keV) + e −. Because the middle isotope is so short-lived, the gamma rays are considered part of the gallium decay. Therefore, the above equations are combined. 73 31 Ga → 73 ...
Types of radioactive decay include gamma ray; beta decay (decay energy is divided between the emitted electron and the neutrino which is emitted at the same time) alpha decay; The decay energy is the mass difference Δm between the parent and the daughter atom and particles.
Iridium-192 is a very strong gamma ray emitter, with a gamma dose-constant of approximately 1.54 μSv·h −1 ·MBq −1 at 30 cm, and a specific activity of 341 TBq·g −1 (9.22 kCi·g −1). [ 4 ] [ 5 ] There are seven principal energy packets produced during its disintegration process ranging from just over 0.2 to about 0.6 MeV .
A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy excited state levels (higher energy levels). ). "Metastable" describes nuclei whose excited states have half-lives 100 to 1000 times longer than the half-lives of the excited nuclear states that decay with a "prompt" half life (ordinarily on the order of 10
A gamma ray cross section is a measure of the probability that a gamma ray interacts with matter. The total cross section of gamma ray interactions is composed of several independent processes: photoelectric effect, Compton (incoherent) scattering, electron-positron pair production in the nucleus field and electron-positron pair production in the electron field (triplet production).