Photons gamma rays

Scatter occurs when the gamma ray photons emitted from the radionuclide in the lung encounter the thorax tissues and change the travelling direction from their origi-... 

The technetium isotope produced is the metastable "mTc, which is in a nuclear excited state. The eventual fall to the ground state has a half-life of 6 hours, and is accompanied by the emission of a gamma-ray photon. The gamma-ray photons have energies sufficiently low not to harm... 

NEAR-Shoemaker also carried a gamma-ray spectrometer (Evans et al., 2001). Gamma-ray photons are emitted from the radioactive decay of long-lived radioisotopes and from other elements that are excited by cosmic-ray bombardment. The gamma rays are... 

Radiochemical Methods in Analytical Chemistry. Activation Analysis with Gamma-Ray Photons and Charged Particles. Chimica 21, No. 3, 116 (1967). 

The gamma ray photons passing through the gas in the cylinder knock electrons out of some of the atoms and these electrons have enough energy to knock electrons out of a great many more atoms. 

Conditions in the universe almost immediately after the big bang were not favorable for the formation of electrons. At that point in time, gamma rays, photons, and neutrinos had very large amounts of energy, much more than was needed to produce electrons. Instead, conditions favored the creation of much more massive particles with large energy equivalents. Among these particles were the muon and the proton. A muon (also known as a mu meson) is a much more massive relative of the electron. It has amass of 1.870 x 10"25 g, about 2,000 times that of an electron. A proton is even heavier, with a mass of about 1.660 x 10 24 g, nearly 3,000 times that of an electron. 

Like electrons, protons, muons, and quarks are formed by the interaction of gamma rays, photons, and neutrinos with a particular amount of energy. The situation for proton formation, for example, involves the interaction of gamma rays and neutrinos with a total energy of about 1,000 MeV ... 

Bremsstrahlung. Gamma-ray photons produced by deceleration of charged particles near the nucleus of an atom. 

In 1955 and 1956, antiprotons and antineutrons were created and detected. The general name for antiparticles is antimatter. As the terminology suggests, when a particle meets its antimatter counterpart, they annihilate each other, leaving pure energy in their place. For example, when a positron collides with an electron, they both disappear, sending out two gamma ray photons (y-tay) in opposite directions. 

Positron-electron collision followed by the creation of two gamma-ray photons... 

Fig. 4.7 Schematic set-up of a SPECT system. One or more gamma cameras slowly rotate around the patient. The gamma cameras detect gamma ray photons that are emitted by a radiopharmaceutical injected into the patient.

Table 32-1 lists the most important (from a chemist s viewpoint) types of radiation from radioactive decay. Four of these types — alpha particles, beta particles, gamma-ray photons, and X-ray photons —can be detected and recorded by the detector systems described in Section 12B-4. Most radittchcniical methods are based on counting the electronic signals produced when these decay particles or photons strike a radiation detector. 

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