On the spatial distribution of the gamma-ray dose from a plane source

1958 ◽  
Vol 4 (1-2) ◽  
pp. 109-111
Author(s):  
U.Ia. Margulis ◽  
A.V. Khrustalev
2007 ◽  
Vol 16 (12b) ◽  
pp. 2399-2405 ◽  
Author(s):  
FRANCESC FERRER ◽  
TANMAY VACHASPATI

Observations of the Milky Way by the SPI/INTEGRAL satellite have confirmed the presence of a strong 511 keV gamma ray line emission from the bulge, which requires an intense source of positrons in the galactic center. These observations are hard to account for by conventional astrophysical scenarios, whereas other proposals, such as light DM, face stringent constraints from the diffuse gamma ray background. Here we suggest that light superconducting strings could be the source of the observed 511 keV emission. The associated particle physics, at the ~ 1 TeV scale, is within the reach of planned accelerator experiments, while the distinguishing spatial distribution, proportional to the galactic magnetic field, could be mapped by SPI or by future, more sensitive satellite missions.


2016 ◽  
Vol 12 (S324) ◽  
pp. 89-90
Author(s):  
Attila Mészáros

AbstractThe Cosmological Principle claims that in the large scale average the visible parts of the universe are isotropic and homogeneous. In year 1998 the author, together with his two colleagues, discovered that the BATSE’s short gamma-ray bursts are not distributed isotropically on the sky. This first discovery was followed by other ones confirming both the existence of anisotropies in the angular distribution of bursts and the existence of huge Gpc structures in the spatial distribution. All this means that these anisotropies should reject the Cosmological Principle, because the large scale averaging hardly can be provided. This was claimed in year 2009. The aim of this contribution is to survey these publications since 1998 till today.


2020 ◽  
Author(s):  
Fabio Terribile ◽  
Simona Vingiani ◽  
Antonio Mileti ◽  
Giuliano Langella

<p>In many contaminated sites and/or sites affected by a potentially toxic element (PTE) contamination, the spatial variability of soil contamination is a very complex issue.</p><p>This is because the history of contamination in a specific industrial site is often lost in time and with very different modifications occurring over time. It is even hidden in the case of illegal waste dumping, for which type, quantity and localization of contaminants are unknown. Thus it is not known in advance (i) the spatial distribution of contamination, (ii) the knowledge about how contaminants have been distributed over and beneath the soil, (iii) how far contaminants have been reworked during the life time of the contaminated site.</p><p>Despite these problems, it is self-evident that a detailed knowledge of the natural and the anthropogenic spatial variability of soil contamination and soil properties is of crucial importance in both site characterization and most importantly in site reclamation.</p><p>Here we claim that the analysis of soil trenches in combination with pXRF can strongly support the understanding about processes behind soil contaminant distribution and this information can then be used in the following study of contaminated site characterization.</p><p>This contribution focuses on how to acquire detailed knowledge of the spatial distribution of contamination in an agricultural area of southern Italy, 6 ha of farmland confiscated by the Italian Judiciary due to past illegal burial of industrial tannery wastes causing potential contamination by Cr, Zn and heavy hydrocarbons (C>12). After indirect geophysical and radiometric (i.e. soil gamma ray emissions) prospections, 8 sites for soil profiles and trenches (10 x 1.7 m wide) digging were identified.</p><p>Over these trenches both morphological (i.e. colour, structure, plant roots, etc.) and elemental total content analysis (Olympus p-XRF) were performed. This analysis enable to identify three type of soil contaminant deposition which affected to various degree the Ap, Bw and C horizons of the investigated Silandic Andosol. The highest Cr and Zn content was found in the B horizon, where levels of 25000 ppm were measured in soil-pockets of muddy-grey materials, very likely hosting the original processing residues.</p>


1993 ◽  
Author(s):  
Charles Meegan ◽  
Gerald Fishman ◽  
Robert Wilson ◽  
Martin Brock ◽  
John Horack ◽  
...  

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