Dispersion Gamma distribution

Fig. 4.4. All-sky map in the light of the 1.809 MeV gamma-ray hne from radioactive aluminium-26. The galactic distribution of aluminium-26, based on data from the COMPTEL (Compton Telescope) experiment aboard the GRO (Gamma-Ray Observatory), suggests that this isotope is dispersed across the Galaxy by the most massive stars, Wolf-Rayet stars and supernovas. Al is formed by the reaction Mg -b p — A1 -b y. This radioactive isotope has a lifetime of about million years and is ejected into space before it begins to decay.

The catalysts, both fresh and used, were characterized as to BET surface area, pore size distribution, elemental analysis, x-ray diffraction and XPS. Some BET and pore volume data are given in Table 1. The diffraction pattern of Catalyst B gave some indication of a gamma-alumina phase, not well resolved All other peaks were well-resolved, suggesting the absence of amorphous or highly-dispersed phases. 

Energy-Dispersive X-Ray Spectroscopy, EDS, is a specific technique for the detection and energy distribution determination of X-Ray Fluorescence, XRR XRF is the phenomena where X rays are emitted from a material when bombarded by high energy radiation (electrons, ions, X rays, neutrons, gamma rays). Some of the X-ray energies emitted are characteristic of the atoms present, allowing atomic identification in the material of interest. 

A substantial body of information is now becoming available on worker exposures in the nuclear facilities of the former Soviet Union (see, e.g., a case-control study of 500 workers 271). Worker exposures involved gamma-irradiation over a wide dose range and exposures to airborne Pu. Particle size distributions of alpha-emitting radionuclides included a large dispersive component with an AMAD of 60-70 pm, a middle dispersive component with an AMAD of 11 -14 pm, and a small component with an AMAD of 0.5 pm. Tokarskaya et al. (271) reported that 162 persons in the 500-person case-control study had contracted lung cancer. Some of these workers were employed before the introduction of special respiratory protection in 1957. 

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