Search

The purpose of this work, investigation of radiation attenuation characteristics, such as mass attenuation coefficient ([micro]/[rho]), molar extinction coefficient ([epsilon]), effective atomic number ([Z.sub.eff]), and electron density ([N.sub.E]), of isolated bacteria from soil samples taken from Diyarbakir in Turkey. The experiments were performed using a narrow beam geometry with the help of the a high-resolution Si(Li) detector and three different radioactive sources at 15 different photon energies. The [epsilon], [Z.sub.eff], and [N.sub.E] values for some bacteria isolated from soil, such as Bacillus megaterium, Bacillus simplex, Bacillus subtilis, and commercially purchased Geobacillus stearothermophilus bacterium, were obtained from the measured [mu]/[rho] results in the energy range from 13.94 to 88.04 keV. The experimental values were checked with two different theoretical results and good agreement was observed among them. The results show that Bacillus simplex bacterium has the highest values of [mu]/[rho] and [Z.sub.eff]and Bacillus subtilis bacterium has the biggest values of [epsilon] and [N.sub.E] among the present bacteria. Key words: bacteria, mass attenuation coefficient, molar extinction coefficient, effective atomic number, effective electron density. Nous examinons ici les parametres caracteristiques d'attenuation par radiation, comme le coefficient d'attenuation de masse ([mu]/[rho]), le coefficient d'extinction molaire (e), le numero atomique effectif ([Z.sub.eff]) et la densite electronique ([N.sub.E]), pour de bacteries extraites d'echantillons de sol pris dans la ville de Diyarbakir en Turquie. Les mesures sont faites en utilisant un faisceau etroit avec un detecteur Si(Li) de haute resolution et trois differentes sources radioactives donnant des photons de quinze energies differentes. Nous obtenons les valeurs de [epsilon], [Z.sub.eff] et [N.sub.E] pour des bacteries extraites du sol, comme Bacillus megaterium, Bacilus simplex et Bacilus subtilis et la bacterie achetee commercialement Geobacilius stearothermophilus, a partir des mesures de [mu]/[rho] dans le domaine d'energie entre 13,94 et 88,04 keV. Ces valeurs experimentales sont comparees a deux ensembles differents de resultats theoriques et l'accord est tres bon. Les resultats montrent que, parmi les bacteries considerees, Bacilius simplex a les plus hautes valeurs de [mu]/[rho] et de Zef, alors que Bacilius subtilis a les plus hautes valeurs de [epsilon] et [N.sub.E]. [Traduit par la Redaction] Mots-cles : bacteries, coefficient d'attenuation de masse, coefficient d'extinction molaire, numero atomique effectif, densite electronique effective., 1. Introduction Bacteria from microorganisms are extensively used in our everyday life and in many fields of science. Bacteria are utilized in the removal of organic (stain materials, etc.) and [...]

The effective atomic numbers and electron densities of some synthesized triazoles were determined using the experimental values of total mass attenuation coefficients at 13.93, 17.77, 26.34, and 59.54 keV photon energies. The measurements were performed in a transmission geometry that consists of a Si(Li) detector, an 241Am point source and a target. The measured results were compared with two different theoretical results. The measured results are generally consistent with the theoretical results. It is observed that the measured parameters depend on the photon energy, weighted contributions of the individual atoms within the triazoles, atom number in the triazoles, and chemical composition of triazoles. Also, the effective electron density increases linearly with increasing effective atomic number.Key words: triazole, total mass attenuation coefficient, shielding, effective atomic number, effective electron density.Nous determinons les valeurs effectives des nombres atomiques et des densites electroniques de certaines triazoles synthetiques, en utilisant les valeurs experimentales des coefficients d'attenuation de masse totale pour des energies de photons de 13,93; 17,77; 26,34 et 59,54 keV. Les mesures sont effectuees dans une geometrie de transmission qui consiste en un detecteur Si(Li), une source ponctuelle de 241Am et une cible. Les resultats des mesures sont compares a deux resultats theoriques differents. Les mesures sont generalement en accord avec les valeurs theoriques. Nous observons que les parametres mesures dependent de l'energie des photons, des contributions ponderees des atomes individuels dans les triazoles, du nombre atomique dans les triazoles et de la composition chimique des triazoles. De plus, la densite electronique effective augmente avec le nombre atomique effectif.Mots-cles : coefficient d'attenuation de masse totale, nombre atomique effectif, densite electronique effective, triazole, ecrantage., 1. IntroductionTriazole is defined as containing three nitrogen and two carbon atoms in the hetero-ring system. Triazoles are generally used in fabricating pharmaceuticals, hormones, corrosion inhibition, agrochemicals, pesticides, and herbicides. [...]

The total attenuation cross section at the K edge, absorption jump ratio, jump factor, Davisson-Kirchner ratio, and oscillator strength parameters for the K shell were determined by measuring the total attenuation cross sections around the K edge for Pr, [Nd.sub.2][O.sub.3], and Sm. The measurements were performed in a secondary excitation geometry using the K[α.sub.2], K[α.sub.1], K[β.sub.1], and K[β.sub.2] X-rays (in the region from 31.817 to 55.293 keV) from different secondary source targets excited by the 59.54 keV γ-photons from an [sup.241]Am annular source. It is the first time that the Davisson-Kirchner ratio values have been determined for present samples. The experimental results were compared with the theoretically calculated and other available experimental results. Key words: total attenuation cross section, jump factor, jump ratio, oscillator strength, Davisson-Kirchner ratio. Nous mesurons la section efficace totale d'attenuation dans la region du seuil de la couche K de Pr, [Nd.sub.2][O.sub.3] et Sm, afin de determiner la section efficace totale d'attenuation au seuil de la couche K, le saut en absorption, le facteur de saut, le rapport Davisson-Kirchner et les forces d'oscillateur pour la couche K. Les mesures se font dans une geometrie d'excitations secondaires utilisant les rayons X K[α.sub.2], K[α.sub.1], K[β.sub.1] et K[β.sub.2] (dans la region de 31.817 a 55.293 keV) de differentes cibles sources secondaires excitees par les photons de 59.54 keV provenant d'une source annulaire de [sup.241]Am. C'est la premiere fois que les valeurs de rapport Davisson-Kirchner sont mesurees pour ces echantillons. Nos resultats sont compares avec des valeurs theoriques et a d'autres resultats de mesure. [Traduit par la Redaction] Mots-cles: section efficace totale d'attenuation, facteur de saut, saut en absorption, forces d'oscillateur, rapport Davisson-Kirchner. PACS Nos.: 32.30.-r, 33.50.Dq, 34.50.-s, 07.85.Nc., 1. Introduction Accurate values of K shell absorption and fluorescence parameters, such as total attenuation cross section, absorption jump ratio, and jump factor, are related the fields of interaction of [...]

The anisotropy parameter values β of the L shell fluorescent X-rays (Lι ([L.sub.3] - [M.sub.1]), L[β.sub.6] ([L.sub.3] - [N.sub.1]), L[α.sub.1,2] ([L.sub.3] - [M.sub.5.4]) and L[β.sub.2,15] ([L.sub.3] - [N.sub.5,4]) of Bi, Pb, Ta, Lu, and Yb excited by 22.6 keV photons were measured. These values were used to determine the kinematic coefficient ratios α(Lι/L[α.sub.1,2]), α(Lι/L[β.sub.6]), and α(L[α.sub.1,2]/L[β.sub.2,15]). The Lι and L[β.sub.6] X-rays were found to be anisotropically emitted whereas L[α.sub.1,2] and L[β.sub.2,15] X-rays showed less anisotropic spatial distributions. Also, the polarization degrees of Lι and Lα X-rays were measured for the present elements and observed that the Lι lines were found to be strongly polarized whereas the Lα lines showed less polarization. PACS Nos.: 78.70.En, 61.80.Cb, 07.85.Nc, 32.30.Rj. Resume: Nous mesurons les valeurs β du parametre d'anisotropie des rayons X fluorescents de Lα couche L, (Lι ([L.sub.3]-[M.sub.1]), L[β.sub.6]([L.sub.3] - [N.sub.1]), L[α.sub.1,2] ([L.sub.3] - [M.sub.5.4]) et L[β.sub.2,15] ([L.sub.3]-[N.sub.5.4]), des elements Bi, Pb, Ta, Lu et Yb excites par des photons de 22.6 keV. Nous utilisons les valeurs obtenues pour determiner les rapports des coefficients cinematique α(Lι/L[α.sub.1,2]), α(Lι/L[β.sub.6]) et α(L[α.sub.1,2]/L[β.sub.2,15]). Nous trouvons que les rayons X Lι et L[β.sub.6] sont emis de facon anisotrope, alors que L[α.sub.1,2] et L[β.sub.2.45] montrent moins d'anisotropie spatiale. Nous mesurons egalement le degre de polarisation des rayons X Lι et Lα et notons que les lignes de Lι sont fortement polarisees, alors que celles de Lα le sont beaucoup moins. [Traduit par Lα Redaction], 1. Introduction The K shell and [L.sub.1] and [L.sub.2] magnetic subshell vacancy states excited with charged particles (protons, electrons, and heavy ions) or photons whose total angular momenta are J [...]