Graviton-induced Bremsstrahlung

We discuss photon Bremsstrahlung induced by virtual graviton exchange in proton-proton interactions at hadronic colliders, resulting from the exchange of Kaluza-Klein excitations of the graviton. The relevant subprocesses, gg to G to e^+e^-gamma and q barq to e^+e^-gamma are discussed in both the ADD and the RS scenarios. Although two-body final states (or real graviton emission) would presumably be the main discovery channels, a search for three-body final states could be worthwhile since such events have characteristic features that could provide additional confirmation. In particular, the k_perp-distribution of the photon is in both scenarios harder than that of the Standard-model background.Comment: 24 pages, including figures. v2: Including initial-state Bremsstrahlung and photon k_perp spectra. Version to appear in PR

Reference levels of natural radioactivity and 137Cs in and around the surface soils of Kestanbol pluton in Ezine region of Çanakkale province, Turkey

PubMed ID: 23802161The aim of the study was to conduct a systematic investigation on the natural gamma emitting radionuclides (226Ra, 232Th and 40K) as well as 137Cs in the surface soils from Kestanbol/Ezine plutonic area in Çanakkale province as part of the environmental monitoring program on radiologic impact of the granitoid areas in Western Anatolia. The activity measurements of the gamma emitters in the surface soil samples collected from 52 sites distributed all over the region has been carried out, by means of HPGe gamma-ray spectrometry system. The activity concentrations of the relevant radionuclides in the soil samples appeared in the ranges as follows: 226Ra was 20-521 Bq kg-1; 232Th, 11-499 Bq kg-1and; 40K, 126-3181 Bq kg-1, yet the 137Cs was much lower than 20 Bq kg -1at most. Furthermore, based on the available data, the radiation hazard parameters associated with the surveyed soils were calculated. The present data also allowed evaluation of some correlations that may exist in the investigated natural radionuclides of the soil samples from the plutonic area in Çanakkale province. It is concluded from the above that the concerned region did not lead to any significant radiological exposure to the environment. © 2013 Copyright Taylor and Francis Group, LLC.Ege Üniversitesi: 2006 FEN 044Financial support for the present work from the Ege University under the following Project 2006 FEN 044 is gratefully acknowledged. We sincerely thank Prof. Dr. Osman Candan and Dr. Cüneyt Akal for their guidance in the field studies. -

A radiological survey of the Egrigöz granitoid, Western Anatolia/Turkey

PubMed ID: 25979749A radiological survey of the granitoid areas throughout Western Anatolia was conducted during 2007-14. As a part of this radiological survey, this article presents results obtained from Egrigöz pluton, which lies in the northeastern region of Western Anatolia. In the investigated area, the activity measurements of the natural gamma-emitting radionuclides (226Ra, 232Th and 40K) in the granitic rock samples and soils have been carried out by means of the NaI(Tl) gamma-ray spectrometry system. The activity concentrations of the relevant natural radionuclides in the granite samples appeared in the ranges as follows: 226Ra, 28-95 Bq kg-1; 232Th, 50-122 Bq kg-1 and 40K, 782-1365 Bq kg-1, while the typical ranges of the 226Ra, 232Th and 40K activities in the soil samples were found to be 7-184, 11-174 and 149-1622 Bq kg-1, respectively. Based on the available data, the radiation hazard parameters associated with the surveyed rocks/soils are calculated. The corresponding absorbed dose rates in air from all those radionuclides were always much lower than 200 nGy h-1 and did not exceed the typical range of worldwide average values noted in the UNSCEAR (2000) report. Furthermore, the data are also used for the mapping of the surface soil activity of natural radionuclides and the corresponding gamma dose rates of the surveyed area. © The Author 2015. Published by Oxford University Press. All rights reserved

Gamma-ray attenuation coefficients and transmission thickness of high consistency heavyweight concrete containing mineral admixture

In the study, high consistency heavyweight concrete mixtures containing barite aggregate were produced by using some common mineral admixtures (viscosity modifier, silica fume and fly ash) at various water/binder ratios and binder contents. Gamma-ray linear attenuation coefficients of the concrete mixtures were determined by using gamma sources of 137Cs and 60Co in NaI(Tl) gamma spectrometry system. The relationship between specimen thickness and transmission of the rays was constituted by emphasizing their mean free path, half-value layer, and tenth-value layer. Moreover, experimental mass attenuation coefficients of the concrete specimens were determined and compared with theoretical mass attenuation coefficients calculated by XCOM software depending on elemental fractions of these concrete in equivalent energies (662 keV, 1173 keV and 1332 keV). As a result, the replacement of the aforementioned admixtures with ordinary cement negatively affected the linear attenuation coefficients of the heavyweight concrete. A relative change of up to 25% was observed between the least and the highest attenuation thickness values at a certain gamma-ray transmission. A good regression relationship has been established between density and linear attenuation coefficients, density and mean free path, and density and half- or tenth-value layers of the heavyweight concrete. Theoretical (XCOM) mass attenuation coefficients were found similar to the experimental mass attenuation coefficients of the heavyweight concretes. Although there is a good linear regression relation between the theoretical and experimental mass attenuation coefficients at 662 keV energy of gamma rays, the relations were disappeared at 1173 and 1332 keV energies of gamma rays. © 2018 Elsevier Lt