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Journal of Nuclear Physics, Material Sciences, Radiation and Applications
Number of Followers: 6  

  This is an Open Access Journal Open Access journal
ISSN (Print) 2321-8649 - ISSN (Online) 2321-9289
Published by Chitkara University Homepage  [9 journals]
  • Simultaneous Grafting of Poly(Acrylic Acid) and Poly(Ethylene Glycol) onto
           Chitosan using Gamma Radiation: Polymer Networks for Removal of Textile
           Dyes

    • Authors: M. D. P. Carreón-Castro; M. Caldera-Villalobos, B. Leal-Acevedo, A. M. Herrera-González
      Abstract: Chitosan is a bio-based polyelectrolyte with high potential for wastewater treatment. Chitosan can remove anionic dyes by adsorption but it has low performance in the removal of cationic dyes. In this work, we report the synthesis of chitosan-based graft-copolymers using gamma radiation. Acrylic acid and poly(ethylene glycol) were grafted successfully onto chitosan applying a radiation dose of 12 kGy at a dose rate of 8 kGyh-1. The grafted-copolymers have improved adsorptive properties for the removal of basic dyes reaching a maximum adsorption capacity higher than 300 mgg-1. The Lanmguir’s isotherm model described satisfactorily the interaction between the grafted copolymers and basic dyes. Freundlich’s isotherm model described the adsorption of anionic dye acid orange 52. The grafted copolymers removed successfully textile dyes from wastewater of the dyeing process. The best results were obtained in the removal of direct and basic dyes. Further, poly(ethylene glycol) grafted on the copolymer conferred better swelling behavior making easy the separation of the adsorbent after dye removal. The results showed that the adsorbent materials synthesized by radiochemical graftcopolymerization are more efficient than the beads, composite materials, and blends of chitosan.
      PubDate: Wed, 10 Feb 2021 15:30:36 +053
       
  • Hydrochemistry and Uranium Concentration in Brackish Groundwater from an
           Arid Zone, Chihuahua, Mexico

    • Authors: Renteria-Villalobos Marusia; Mendieta-Mendoza Aurora, Montero-Cabrera María Elena, Manjón-Collado Guillermo, Galván-Moreno José Antonio
      Abstract: In arid zones, the principal water supply is from groundwater, which can present high concentration of salts, heavy metals, and radioactive elements. The aim of the study was to determine isotopic uranium concentration in groundwater samples with high concentration of salts and its association with other chemical species. Samples were taken from wells with high salt content. The 238,234U radioisotope concentrations were determined by liquid scintillation and alpha-particle spectrometry. In addition, the physical-chemical parameters were recorded in situ; whereas the dissolved ions and elemental composition were measured by UV-Vis and X-ray fluorescence spectrophotometry, respectively. To obtain isotopic uranium concentrations, three radiochemistry procedures were carried out. An ANOVA test was performed to compare the results from procedures, as well as an analysis of Pearson correlation was used between parameters to obtain their associations. Statistically, the U isotopic concentrations did not show differences (p-value 0.82) between procedures. 238U and 234U showed mean concentrations of 6.7 mBq mL-1 and 16.6 mBq mL-1, respectively, with an Activity Ratioby up 7.2. The groundwater under study showed high concentration of TDS, calcium, sulphate, chloride, nitrate, and nitrite. Isotopic U concentrations tend to increase with NO3>Zn>Cl>Br>SO4>Cu>T>SDT>P; meanwhile their contents decrease with T>Cl->NO2>Fe. These findings help us to understand the uranium behavior in groundwater with high salt contents as well as the influence of agricultural supplies on chemical species presents in groundwater.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • GEANT4 Study of Proton–Body Interactions

    • Authors: J. A. López; S. S. Romero González, O. Hernández Rodríguez, J. Holmes, R. Alarcon
      Abstract: Proton therapy uses a beam of protons to destroy cancer cells. A problem of the method is the determination of what part of the body the protons are hitting during the irradiation. In a previous study we determine that by capturing the gamma rays produced during the irradiation one can determine the location of the proton-body interaction, in this work we investigate if by examining the gamma rays produced it is possible to determine the body part that produced the gamma rays by the proton collision. This study uses GEANT4 computer simulations of interactions of proton-tissue, protonbrain, proton-bone, etc., which produce gamma rays, to determine the characteristics of the gamma rays produced. We then analyze the characteristics of the gamma rays to find signatures that could be used to determine the source of the rays. In particular, we study the distribution of gamma ray energies, their full-width half-maximum, energy resolution, maximum height, and total number of counts. This study concludes that it is possible to use the gamma ray spectra to determine what body part produced it.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Optimization of the Position of the CR-39 Polycarbonate Sheet Inside the
           Solid State Track Detector “Measuring Device” Through Computational
           Fluid Dynamics Technique

    • Authors: A. Lima Flores; R. Palomino-Merino, V. M. Castaño, J. I. Golzarri, G. Espinosa
      Abstract: The “measuring device” is one of the most reliable, efficient and economic indoor radon dosimeters that exist. This device was developed by the Proyecto de Aplicaciones de la Dosimetría (PAD) at the Physics Institute of UNAM (IF-UNAM) and consists of a transparent rigid plastic cup, a CR-39 polycarbonate sheet and a standard size metal clip that is used to hold the polycarbonate in the center of the cup. The cup is wrapped and covered with a low-density polyurethane protector in order to prevent the detector from being irradiated by ionizing particles found in the environment. In this work, an analysis was carried out that allowed to understand how the radon concentration on the polycarbonate sheet varies when its height is changed with respect to the base of the plastic cup, in order to understand what position increase the probability of interaction between radon and the surface of the detector. For the development of this work, four computational simulations were performed with the technique called Computational Fluid Dynamics (CFD). The results shows that as the CR-39 is positioned more closed to the base of the cup, the probability of interaction of the radon and the detector increase. Based on these results it is concluded that, when there is a limit in the time in which a measuring device can be placed in the zone where it is desired to quantify indoor radon, it is recommended to collocated the CR-39 at 1 cm with respect to the base of the cup.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Charged Lepton Masses as a Possible CPV Source

    • Authors: O. Félix-Beltrán; J. E. Barradas-Guevara J. E. Barradas-Guevara, F. González-Canales
      Abstract: We realize a model-independent study of the so-called Tri-Bi-Maximal pattern of leptonic flavor mixing. Different charged lepton mass matrix textures are studied. In particular, we are interested in those textures with a minimum number of parameters and that are able to reproduce the current experimental data on neutrino oscillation. The textures studied here form an equivalent class with two texture zeros. We obtain a Tri-Bi-Maximal pattern deviation in terms of the charged leptons masses, leading to a reactor angle and three CP violation phases non-zero. These lastest are one CP violation phase Dirac-like and two phases Majorana-like. Also, we can test the phenomenological implications of the numerical values obtained for the mixing angles and CP violation phases, on the neutrinoless double beta decay, and in the present and upcoming experiments on long-base neutrino oscillation, such as T2K, NOvA, and DUNE.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Formic Acid Ionization and Fragmentation by Multiphoton Absorption

    • Authors: C. Cisneros; T. Bautista, C. F. Betancourt, E. Prieto, A. Guerrero, I. Álvarez
      Abstract: Multiphoton absorption is an intensity dependent nonlinear effect related to the excitation of virtual intermediate states. In the present work, multiphoton ionization and dissociation of the formic acid molecule (HCOOH) by the interaction with photons from 532 Nd: YAG laser at different intensities are discussed, using different carrier gases. The induced fragmentation-ionization patterns show up to 17 fragments and dissociation channels are proposed. Some evidence of small clusters formation and conformational memory from the ratio of the detected products, CO+ and CO2+, on the light of the available results, it is possible to conclude that they arise from trans and cis formic acid. Our results are compared with those obtained in other laboratories under different experimental conditions, some of them show only partial agreement and differences are discussed. Following the Keldysh description it is possible, from our experimental parameters, characterize our results, in the multiphoton absorption regime.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Determination of 234U and 238U Activities in Soil by Liquid Scintillation
           and High-Resolution Alpha Spectrometry

    • Authors: Montero-Cabrera María Elena; Caraveo-Castro Carmen del Rocío, Méndez-García Carmen Grisel, Mendieta-Mendoza Aurora, Rentería-Villalobos Marusia, Cabral-Lares Rocío Magaly
      Abstract: Uranium is a radioactive element with a special presence in the rocks, waters, sediments, soils, and plants at the state of Chihuahua. The activity ratio of 238U/234U is used to explain the uranium transport by surface water and its deposition in arid environments. In this work, the activity concentration of natural U isotopes is determined by PERALS liquid scintillation and high-resolution alpha spectrometry (AS, Canberra camera 7401VR) in the Environmental Radiological Surveillance Laboratory (LVRA) at CIMAV, Chihuahua. Uranium is extracted from soils through the scintillating liquid extractor URAEX for PERALS, with chemical recovery (CR) of 80 - 85 %, and through the ion exchange resin UTEVA + electrode position by the Hallstadius method, with CR of 85 - 90 %, for AS. The procedures of 234U and 238U activity concentration (AC) determination in soils were validated by their application to the certified reference material IAEA-375. The resulting values were in the reference range of the certified or informative values. Both procedures were applied to 6 representative soil samples, with AC of the same order of magnitude or greater, and similar CR and compatible results. Both procedures are satisfactory for the purposes of LVRA research and in general.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Surface Modification of Polypropylene by Atmospheric Pressure Plasma

    • Authors: O. Xosocotla; H. Martinez, B. Campillo
      Abstract: In this investigation, we studied the influence of atmospheric pressure plasma treatment on the surface properties of polypropylene (PP). The PP samples were treated for various durations using a gliding arc plasma source with air as a working gas. The formation of polar groups (–OH and C = O) on the PP surface after plasma treatment was evaluated and analyzed using Raman spectroscopy and attenuated total reflection–Fourier transform infrared spectroscopy. The contact angle was measured using polar and non-polar liquids to obtain the polar and dispersive components as well as the surface free energy of the PP before and after treatment. A sevenfold increase after treatment was observed for the polar component, while hydrophobicity decreased 73% after treatment. Finally, changes in topography were observed using atomic force microscopy (AFM) analysis before and after plasma treatment. AFM images showed that under atmospheric treatment, the PP surface underwent etching, reducing the surface roughness. Microhardness measurements of the films also revealed significant changes in mechanical properties after plasma treatment.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Structural Shielding Design of CT Facility using Monte Carlo Simulation

    • Authors: Ashwani Kumar Yadav; Basilia Quispe Huillcara, Pablo Víctor Cerón Ramírez, Modesto Antonio Sosa Aquino, Miguel Ángel Vallejo Hernández
      Abstract: Radiation application in medicine offers extraordinary benefits. But radiation is like a double-edged sword, it has both benefits and associated risks on the community in contact. To justify the safety of workers and members of the public, regulated use of radiation is assessed by the radiation protection protocols. The aim of this study is to design a Computed Tomography (CT) facility with a simplified model of CT scanner, whose shielding follows the guidelines of National Council on Radiation Protection and Measurements (NCRP) Report No. 147. To design the study model, Monte Carlo (MC) radiation transport code in MCNPX 2.6.0 was used for the simulation. Furthermore, MCNPX was used to measure the photon flux in a vicinity or the detector cell. To validate the functioning of the X-ray tube, the experimental results were compared with the X-ray Transition Energies Database of National Institute of Standards and Technology, U.S. Department of Commerce. The results obtained were within 0.60% of relative error. To confirm the functioning of shielding design, radiation protection quantity, air kerma was measured at several points outside, and inside of the CT room and they were under the radiation dose recommended by NCRP, which demonstrates that the shielding design was
      successful in blocking the radiation. The study can be used for an easy evaluation of any CT room within the framework of the model of the study.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Superficial Surface Treatment using Atmospheric Plasma on Recycled Nylon
           6,6

    • Authors: M. Rodríguez; E. Vázquez-Vélez, H. Martinez, A. Torres
      Abstract: Polymers currently represent materials that are cost-effective, while its recycled nature is significant in terms of environmental protection. However, the surface properties of polymers often do not meet the demands of wettability, adhesion, and friction, among others. Atmospheric plasma treatment on the surface of polymers improves its physical-chemistry properties. In this work, a recycled nylon coating was prepared by the spin coating technique and characterized by Fourier transform infrared spectroscopy and X-ray diffraction. This coating was treated by atmospheric plasma, and Raman spectroscopy was performed to analyze the signals related to different functional groups present in the coating surface after plasma treatment. The action of plasma on the surface morphology was observed by scanning electron microscopy. The contact angle results showed an improvement in surface wettability.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Simulation of Dose Estimations from Solar Protons: A PMMA-Bi2O3 Shielding
           Model for Space Exploration

    • Authors: L. Sajo-Bohus; J. A. López, M. Castro-Colin
      Abstract: Adverse effects of long-term exposure to galactic cosmic radiation (GCR) pose a non negligible obstacle for future space exploration programs; the high-LET-particle-rich environment has an adverse effect on human health. Concomitant to GCR we have as well solar particle radiation. Long term space exploration will rely on adequate and highly efficient shielding materials that will reduce exposure of both biosystems and electronic equipment to GCR and solar particles. The shield must attenuate efficiently heavy GCR ions, by breaking them up into less-damaging fragments and secondary radiation: biologically damaging energetic neutrons and highly charged and energetic HZE- particles. An approach to this problem is the development of shielding compounds. Shielding materials should address the conditions of different aspects of a given mission, e.g. time duration and travel path. The Monte Carlo method (GEANT4) is here employed to estimate the effects of a shielding material based on the recently developed Bi2O3-based compound (Cao et al., 2020). In the present study GEANT4 code is used to make estimations of attenuation of solar protons. The objective is to provide some insight about the effect of the new composite shield that has an intrinsic capability for dose reduction.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Changes of the Neutron Flux of the Nuclear Reactor Triga Mark III Since
           the Conversion from High to Low 235U Enrichment

    • Authors: C. Vázquez-López; O. Del Ángel-Gómez, R. Raya-Arredondo, S. S. Cruz-Galindo, J. I. Golzarri-Moreno, G. Espinosa
      Abstract: The neutron flux of the Triga Mark III research reactor was studied using nuclear track detectors. The facility of the National Institute for Nuclear Research (ININ), operates with a new core load of 85 LEU 30/20 (Low Enriched Uranium) fuel elements. The reactor provides a neutron flux around 2 × 1012 n cm-2s-1 at the irradiation channel. In this channel, CR-39 (allyl diglycol policarbonate) Landauer® detectors were exposed to neutrons; the detectors were covered with a 3 mm acrylic sheet for (n, p) reaction. Results show a linear response between the reactor power in the range 0.1 - 7 kW, and the average nuclear track density with data reproducibility and relatively low uncertainty (±5%). The method is a simple technique, fast and reliable procedure to monitor the research reactor operating power levels.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Radon Dose Determination and Radiological Risk in Some Mexican Caves with
           CR-39 Detectors

    • Authors: A. Chavarria; J. I. Golzarri, G. Espinosa
      Abstract: Radon (222Rn) is a radioactive gas, from the 238U decay chain, that contributes in large part of the natural radiation dose to which humans are exposed. Radon is the second cause of lung cancer after tobacco. The US-EPA considers a concentration of 148 Bq/m3 for homes and 400 Bq/m3 for workplaces as the reference level. Caves are closed spaces where 222Rn, which emanates from the surrounding minerals and rocks, can accumulate and reaches large concentrations that can represent a health risk for the guides, speleologists and visitors who spend time in these spaces. This work uses the previously recorded radon concentrations in 8 caves in Mexico and calculates the average dose range and the average annual dose for each of them with the “Wise” public domain program (http://www.wise-uranium.org/rdcrn.html) to determine the level of radiological risk with 2,000 1,000 and 500 working hours per year. Karmidas cave had the highest average 222Rn concentration with 27,633.3 Bq/m3 and for 2,000 working hours per year an average annual dose rate of 347.1 mSv/y. Los Riscos cave had the lowest average concentration with 384.7 Bq/m3 and for 2,000 working hours per year an average annual dose rate of 4.832 mSv/y. These results show that all the caves studied present values,
      with 2,000 working hours per year, that exceed 3 mSv/y for workplaces and must be considered by the people who work in these places. A casual tourist visiting the caves does not present any radiological risk, while guides and speleologists should consider it.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Wear Behavior of a Ni/Co Bilayer Coating by Physical Vapor Deposition on
           AISI 1045 Steel

    • Authors: E. Pardo L; S. E. Rodil, B. Campillo, I. Dominguez, J. G. González-Rodriguez, H. Martinez
      Abstract: Coatings by physical vapor deposition (PVD) have become highly relevant due to their wide range of applications and the rapid rate of coating formation. In this work, AISI steel 1045 was coated with two layers, Ni and Co using the PVD technique. Each coating was deposited with a thickness of 1 μm. After applying the coatings, a post-treatment was applied in an AC plasma reactor using a boron nitride blank in an Ar atmosphere at a pressure of 3 Torr, 0.3 A, and 460 V at 4, 8, and 12h. The post-treatment was characterized by optical emission spectroscopy (OES) in a range of 200-1100 nm. The main species observed by OES were Ar+, N2, N2+, and B+. The coatings on 1045 steel and posttreatment were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Also, were subjected to tribological tests to analyze wear resistance, using the Pin-on-Disk technique. The coatings on steel 1045 present remarkably better wear properties than the uncoated 1045 steel, being the sample post-treated at 4h that showed a lower wear rate.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Study through Geant4, for Time Resolution characterization of different
           detectors arrays coupled with two SiPMs, as a function of: the
           scintillator plastic material, its volumetric dimensions and the location
           of the radiation emission source

    • Authors: C. H. Zepeda Fernández; Hernández Aguilar Javier Efrén, E. Moreno-Barbosa
      Abstract: The high time resolution detectors are relevant in those experiments or simulations were the particles to detect, have a very short time of flight (TOF), and due this it´s required that the detections times are ranged between ns. & ps.
      Using Geant4 software, it was made thirty simulations of coupled detectors to plastic scintillators with two silicon photomultipliers (SiPMs) located on the scintillator’s central sides. To characterize the time resolution, it was required to quantify the optical photons that reach the Score in a certain time, which are generated by muons on the surface of the plastic scintillator. Different configurations of muon beams were simulated at energy of 1 GeV, to interact with the configuration of the scintillator material of its corresponding arrangement. The simulations were made varying three parameters: the scintillator material “BC404 & BC422”, its size, and the location of the radiation source. Fifteen simulations correspond to BC404 material & fifteen simulations to BC422 material respectively. The first five simulations consisted in varying the scintillator’s volumetric size and collocate the muons beam guided randomly distributed over it, the next five simulations differentiate from setting up a directly centered beam, and the last five simulations for guide the beam on the left lower corner of each scintillator.
      The best time resolution achieved was σ= 8.67 +/− 0.26 ps., reported by the detector with BC422 scintillator material which has a volume of 20x20x3 mm3.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Receptor Binding Domain (RBD) Structural Susceptibility in the SARS-CoV-2
           Virus Spike Protein Exposed to a Pulsed Electric Field

    • Authors: D. Osorio-González; V. J. Muñiz-Orozco, C. P. González, M. Fuentes-Acosta, J. Mulia-Rodríguez, L. A. Mandujano-Rosas
      Abstract: SARS-CoV-2 is responsible for causing the Coronavirus disease 2019 (COVID-19) pandemic, which has so far infected more than thirty million people and caused almost a million deaths. For this reason, it has been a priority to stop the transmission of the outbreak through preventive measures, such as surface disinfection, and to establish bases for the design of an effective disinfection technique without chemical components. In this study, we performed in silico analysis to identify the conformational alterations of the SARS-CoV-2 Spike Receptor Binding Domain (RBD) caused by the effect of a pulsed electric field at two different intensities. We found that both stimuli, especially the one with the highest angular frequency and amplitude, modified the electrical charge distribution in the RBD surface and the number of hydrogen bonds. Moreover, the secondary structure was significantly affected, with a decrease of the structured regions, particularly the regions with residues involved in recognizing and interacting with the receptor ACE2. Since many regions suffered conformational changes, we calculated RMSF and ΔRMSF to identify the regions and residues with larger fluctuations and higher flexibility. We found that regions conformed by 353-372, 453-464, and 470-490 amino acid residues fluctuate the most, where the first is considered a therapeutic target, and the last has already
      been characterized for its flexibility. Our results indicate that a pulsed electric field can cause loss of stability in the Spike-RBD, and we were able to identify the vulnerable sites to be used as a starting point for the development of viral inhibition or inactivation mechanisms.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Gamma Irradiation of Aqueos Solution of L-Aspartic Acid, L-Aspartic Acid
           in Solid State, and L-Aspartic Acid Adsorbed into Na-Montmorillonite: Its
           Relevance in Chemistry Prebiotic

    • Authors: A. Meléndez-López; M. F. García-Hurtado, J. Cruz-Castañeda, A. Negrón-Mendoza, S. Ramos-Bernal, A. Heredia
      Abstract: Aspartic acid is an amino acid present in the modern proteins, however, is considered a primitive amino acid hence its importance in prebiotic chemistry experiments studies. In some works of prebiotic chemistry have been studied the synthesis and the stability of organic matter under high energy sources, and the role of clays has been highlighted due to clays that can affect the reaction mechanisms in the radiolytic processes. The present work is focused on the study of the role of Namontmorillonite in the gamma radiolysis processes of L-aspartic acid. Gamma radiolysis processes were carried out in three different systems a) L-aspartic acid in aqueous solution; b) L-aspartic acid in solid-state; and c) L-aspartic acid adsorbed into Na-montmorillonite. L-aspartic acid was analyzed by high-performance liquid chromatography−electrospray ionization−mass spectrometry (HPLCESI-MS). The results showed that the decomposition of L-aspartic acid considerably decreased in the presence of clay thus highlighting the protector role of clays and favors the stability of organic matter even under the possible high energy conditions of primitive environments. The principal product of
      gamma radiolysis of L-aspartic acid was succinic acid produced by deamination reaction. On the other hand, when aspartic acid was irradiated in solid-state the main product was the L-aspartic acid dimer. Both radiolysis products are important for chemical evolution processes for L-aspartic acid in primitive environments.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Surface modification of polyethylene terephthalate (PET) by corona
           discharge plasma

    • Authors: O. Flores; B. Campillo, F. Castillo, H. Martínez, J. Colín
      Abstract: Surface modification of polyethylene terephthalate (PET) was studied by corona discharge plasma at different exposure times using air as working gas. The modification of the surface properties are characterized, those are morphology and wettability. Corona plasma treatment was found to modify the PET surface in both morphology and wettability. The corona discharge at atmospheric pressure is a heterogeneous with multiple current pulses, which generates an asymmetric pattern of erosion on the PET surface. The corona discharge treatment erodes the surface and therefore modifies the surface morphology. The roughness of the PET surface increases in the impact point of the corona discharge on the PET surface. An increase in the wettability of PET was also observed after corona discharge treatment at atmospheric pressure.
      PubDate: Wed, 10 Feb 2021 00:00:00 +053
       
  • Effect of Magnetic Fields on Charged B Meson Decays

    • Authors: Sukadev Sahoo; M. Kumar
      Abstract: The effect of magnetic fields on the leptonic decay of charged B meson B− → l-v- is investigated. The decay rate of the process is calculated both in the absence and presence of magnetic field. The non-perturbative parameters fB± (B), f'B± and MB±(B) are also estimated.
      PubDate: Wed, 30 Dec 2020 16:40:47 +053
       
  • Cluster Radioactivity

    • Authors: D. N. Poenaru; R. A. Gherghescu
      Abstract: Cluster radioactivity (spontaneous emission of heavy particles from nuclei) is presented from theoretical point of view in good agreement with experimental results. After a brief hystorical account we give details about the analytical super asymmetric fission (ASAF) model extensively used for predicting the half-lives of heavy and superheavy (Z ≥ 104) elements. For the already measured 26 cluster decays (from 14C to 32,34Si of parent nuclides with Z = 87-96) it is clear that cluster radioactivity is a rare phenomenon in the best case about 9 orders of magnitude weaker than the competing alpha decay. Then we show the theoretical possibility of a strong cluster decay compared to alpha decay for some superheavy nuclei with Z ≥ 122, e.g. 306122; 310-314122; 306-324124, and 311-323124.
      PubDate: Thu, 03 Dec 2020 00:00:00 +053
       
  • Determination of Gamma-Ray Shielding Parameters for Concretes and
           Dosimeters Using MCNPX

    • Authors: V. P. Singh; Huseyin Ozan Tekin
      Abstract: Gamma-ray shielding parameter for some concretes and dosimeters having large scale applications in radiological protection are presented using MCNPX (version 2.4.0) at different energies. The MCNPX results are compared with experimental, MCNP and XCOM data, and good agreement is being noted. Present study indicates that MCNPX simulation method is suitable and reliable simulation tool to be used as an alternative method for the investigation of gamma-ray interaction. The present geometry can be used as standard geometry for MCNPX simulation for low- as well as high-Z materials.
      PubDate: Thu, 03 Dec 2020 00:00:00 +053
       
  • Theoretical Study on the Formation of 1-neutron and 2-neutron Halo Nuclei
           via Decay of Elements in Super-Heavy Region

    • Authors: R.K. Biju; K. Prathapan, K.P. Anjali
      Abstract: The possibility for the existence of 1-neutron and 2-neutron halo nuclei through the decay of even-even nuclei 270-316116, 272-318118 and 278-320120 in the super-heavy region is studied within the frame work of the Coulomb and Proximity Potential Model (CPPM). Halo structure in neutron rich nuclei with Z<=20  is identified by calculating the neutron separation energies and on the basis of potential energy considerations. The 1n + core configuration of proposed 1-neutron halo nuclei between z=10  and Z=20 is found shifted to 2n + core configuration in higher angular momentum states. The calculation of half-life of decay is performed by considering the proposed halo nuclei as spherical cluster and as deformed nuclei with a rms radius. Except for 15C, the half-life of decay is found decreased when the rms radius is considered. Only the 1-neutron halo nuclei 26F and 55Ca showed half-lives of decay which are less than the experimental limit. None of the proposed 2-neutron halo nuclei have shown a half-life of decay lower than the experimental limit. Also, the probability for the emission of neutron halo nuclei is found to be less in super-heavy region when compared with the clusters of same isotope family. Further, neutron shell closure at neutron numbers 150, 164 and 184 is identified form the plot of  log10 T1/2 verses the neutron number of parents. The plots of Q-1/2 verses log10 T1/2 and -ln P verses log10 T1/2 for various halo nuclei emitted from the super-heavy elements are found to be linear showing that Geiger-Nuttall law is applicable to the emission of neutron halo also.
      PubDate: Mon, 09 Nov 2020 00:00:00 +053
       
  • Design and Development of a Mini-Orange Magnetic Spectrometer with
           Multichannel Facility for Conversion Electron Spectroscopy

    • Authors: K. Venkataramaniah; M. Sainath, K.Vijay Sai, Dwarakarani Rao, Deepa Seetharaman
      Abstract: Background: Conventional magnetic spectrometers used for conversion electron detection are very cumbersome, require strong magnetic fields and the spectra have to be scanned point by point and have very low transmission. A magnetic filter using permanent magnets and an Si(Li) detector would facilitate multichannel analysis with high transmission. The mini-orange is a new type of spectrometer for conversion electrons combining a solid state Si(Li) detector with a filter of permanent magnets around a central absorber of lead.
      Purpose: An indigenously developed magnetic spectrometer if optimized properly would be of great use in conversion electron spectroscopy for both online and offline experiments.
      Methods: A Mini-Orange magnetic spectrometer made of small permanent magnets has been designed and developed indigenously and optimized for its best performance condition. The transmission curves for different energy regions are plotted using the conversion electron spectra from the standard gamma transitions from 153Gd, 169Yb and 131Ba decays. The optimized spectrometer facilitates multichannel acquisition of conversion electron spectra for precision electron spectroscopy. The system also can be used in in-beam experiments with minor modifications of the vacuum chamber.
      Results: The optimized spectrometer was used for precision electron spectroscopy. Experimental transmission curves are then obtained by plotting Transmission (T) against the corresponding electron energy for low energy, medium energy and a broad energy range. Out of the several experiments done the optimum settings for f and g, that resulted in this curve, is identified at f = 7.5 cm and g = 4.5 cm.
      Conclusions: The optimized spectrometer facilitates multichannel acquisition of conversion electron spectra for precision electron spectroscopy. The system also can be used in in-beam experiments with minor modifications of the vacuum chamber.
      PubDate: Mon, 09 Nov 2020 00:00:00 +053
       
  • Various Experimental factors behind the Missing Elements in PIXE Spectrum
           of Charnockite Matrix

    • Authors: A. V. S. Satyanarayana; M. Jagannadha Rao
      Abstract: In the chemical characterization of charnokite is well investigated by using PIXE and other analytical techniques, but PIXE not given information about some of elements completely, because every technique including PIXE has proper limitations. To obtain the complete geochemical explanation of matrix charnockite composition, the experimental factors behind missing elements in PIXE at 3 MeV techniques with comparison must known and hence are used for the analysis of matrix compositions related to the earth materials like charnockite. In this study, the results obtained from PIXE compared with other analytical techniques and experimental factors of PIXE are discussed. By investigating the geochemical nature of complex charnockite material, the experimental factors which are related to the missing elements in this study of wide range of elements obtained from PIXE spectrum through the previous analytical techniques have been discussed.
      PubDate: Mon, 09 Nov 2020 00:00:00 +053
       
  • Beta Decay Studies of Nuclides in the Heavy Region

    • Authors: M. K. P. Rajan; R. K. Biju, K. P. Santhosh
      Abstract: In the present work we studied the β-decay of various isotopes in the heavy region using the empirical formula of Fiset and Nix. It is found from the half-life that as the neutron number increases the possibility of β-decay increases. From the dependence of beta decay half-life on neutron number of parent and Q-value, we modified empirical formula of Fiset and Nix for beta decay half-life. We also developed an empirical formula for the Z-value of most stable isobar against β-decay. From the study of mass parabola for different isobars with mass number ranging from 200-223 it was found that the lowest point in the parabola, which is the Z-value of most stable isobar against β-decay, matches well with our formula predictions.
      PubDate: Mon, 09 Nov 2020 00:00:00 +053
       
  • Cluster radioactivity in superheavy nuclei 299-306122

    • Authors: H. C. Manjunatha; S. Alfred Cecil Raj, A. M. Nagaraja, N. Sowmya
      Abstract: Cluster radioactivity is an intermediate between alpha decay and spontaneous fission. It is also an exotic decay obtained in superheavy nuclei. When a cluster decay is detected in superheavy nuclei, the daughter nuclei is having near or equal to doubly magic nuclei. We have investigated cluster decay of isotopes of He, Li, Be, Ne, N, Mg, Si, P, S, Cl, Ar and Ca in the superhaevy nuclei region 299-306122. We have also compared the logarithmic half-lives of cluster decay with that of other models such as Univ [1], NRDX [2], UDL [3] and Horoi [4]. From this study it is concluded that  cluster decay of 4He, 22Ne, 26Mg, 28Si 30Si, 34S, 40Ca and 46Ca are having shorter logarithmic half-lives compared to exotic cluster decay modes.
      PubDate: Mon, 09 Nov 2020 00:00:00 +053
       
  • Homogenization Effects of VVER-1000 Fuel Assembly on Criticality
           Calculations

    • Authors: SM Shauddin
      Abstract: Due to cost effective and simplicity homogeneous reactors have been widely used for experimental and research purposes. Parameters which are difficult to get from a heterogeneous reactor system can be easily obtained from a homogeneous reactor system and can be applied in the heterogeneous reactor system if the major parametric differences are known. In this study, homogenization effects of VVER (Water Water Energetic Reactor)-1000 fuel assembly on neutronic parameters have been analyzed with the universal probabilistic code MCNP (Monte Carlo N-Particle). The infinite multiplication factor (k∞) has been calculated for the reconfigured heterogeneous and homogenous fuel assembly models with 2 w/o U-235 enriched fuel at room temperature. Effect of mixing soluble boron into the moderator/coolant (H2O) has been investigated for both models. Direct and fission detected thermal to higher energy neutron ratio also has been investigated. Relative power distributions of both models have been calculated at critical and supercritical states. Burnup calculations for both the reconfigured cores have been carried out up to 5 years of operation. Effective delayed neutron fraction (βeff) and prompt removal lifetime (ℓ) also have been evaluated. All the results show significant differences between the two systems except the average relative power.
      PubDate: Mon, 10 Aug 2020 15:02:44 +053
       
  • Dose rate profile inside the spent fuel storage pool in case of full
           capacity storage

    • Authors: Amr Abdelhady
      Abstract: This study aims to evaluate the radiation dose rate distribution inside temporary spent fuel open-pool storage. The storage pool is connected to the main pool via transfer channel to facilitate transporting the spent fuel under water that avoiding radiation dose rising in the working area in the reactor. The storage pool was prepared to store 800 spent fuel elements that considering the maximum capacity of storage. The spent fuel elements in the storage pool have different decay times depending on the times of extraction from the core. Assuming conservatively, that the spent fuels of the 5-years decay time would be stored in the lower rack and the spent fuels, of decay time ranged between 10 days and 5 years, would be stored in the upper rack. The dose rate was profiled in the region above the upper rack using SCALE/MAVRIC code applying adjoint flux calculation as a variance reduction technique. The results show that the dose rate values in the region above the pool surface would be lower than the permissible limits.
      PubDate: Mon, 10 Aug 2020 00:00:00 +053
       
  • On the role of nuclear quantum gravity in understanding nuclear stability
           range of Z = 2 to 118

    • Authors: UVS Seshavatharam; S Lakshminarayana
      Abstract: To understand the mystery of final unification, in our earlier publications, we proposed two bold concepts: 1) There exist three atomic gravitational constants associated with electroweak, strong and electromagnetic interactions. 2) There exists a strong elementary charge in such a way that its squared ratio with normal elementary charge is close to reciprocal of the strong coupling constant. In this paper we propose that, ℏc can be considered as a compound physical constant associated with proton mass, electron mass and the three atomic gravitational constants. With these ideas, an attempt is made to understand nuclear stability and binding energy. In this new approach, with reference to our earlier introduced coefficients k = 0.00642 and f = 0.00189, nuclear binding energy can be fitted with four simple terms having one unique energy coefficient. The two coefficients can be addressed with powers of the strong coupling constant. Classifying nucleons as ‘free nucleons’ and ‘active nucleons’, nuclear binding energy and stability can be understood. Starting from , number of isotopes seems to increase from 2 to 16 at and then decreases to 1 at For Z >= 84, lower stability seems to be, Alower=(2.5 to 2.531)Z.
      PubDate: Mon, 02 Mar 2020 14:32:52 +053
       
  • Effects of Gamma Irradiation on Curcumin

    • Authors: E. Islas-Ortiz; E. O. Reyes-Salas, A. Negrón-Mendoza, A. L. Meléndez-López, G. Reyes-García, J. A. Cruz- Castañeda, E. Madrigal-Lagunas
      Abstract: In this study, remnants concentrations of curcumin in Curcuma longa (organic turmeric powder) were determined after it was exposed to irradiation doses of 1, 2 and 3 kGy. Curcumin analysis was performed using the analyte-sensitive impulse differential polarography technique (LOD: 0.621 ppm and LOQ: 2.130 ppm). The results obtained showed a decreasing concentration of curcumin as a function of the irradiation dose. This reduction is low in terms of affecting the product’s quality with respect to its concentration.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Feasibility of Formation of Ge1-x-y Six Sny Layers With High Sn
           Concentration via Ion Implantation

    • Authors: Randall L. Holliday; Joshua M. Young, Satyabrata Singh, Floyd D. McDaniel, Bibhudutta Rout
      Abstract: By increasing the Sn concentration in Ge1-ySny and Ge1-x-ySixSny systems, these materials can be tuned from indirect to direct bandgap along with increasing electronic and photonic properties. Efforts have been made to synthesize Sn-Ge and Ge-Si-Sn structures and layers to produce lower energy direct bandgap materials. Due to low solid solubility of Sn in Ge and Si-Ge layers, high concentrations of Sn are not achieved by traditional synthesis processes such as chemical vapor deposition or molecular beam epitaxy. Implantation of Sn into Si-Ge systems, followed by rapid thermal annealing or pulse laser annealing, is shown to be an attractive technique for increasing Sn concentration, which can increase efficiencies in photovoltaic applications. In this paper, dynamic ion-solid simulation results are presented. Simulations were performed to determine optimal beam energy, implantation order, and fluence for a multi-step, ion-implantation based synthesis process.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Spectrophotometric Study of Polymeric DyesGels After a Gamma Irradiation
           Process for its Possible Use as a Radiation Dosimeter

    • Authors: A L Meléndez-López; M F García-Hurtado, J Cruz-Castañeda, A Negrón-Mendoza, S Ramos-Bernal, A Heredia
      Abstract: This work aims to evaluate a dosimetric system composed of green malachite supported in agarose. Previous work showed that solutions of green malachite irradiated at 1 to 40 kGy present a linear behavior. This system is a gel composed of green malachite (2.5×10–3 M), sodium benzoate (1%),
      and agarose (1%) that was exposed tovarious doses of gamma irradiation. The irradiated systems were measured with a UV-V is spectrophotometer at 619 nm. Experimental parameters (such as dose rate, doses, and temperature) were controlled and optimized for reproducible and reliable results. More studies are needed to propose a dosimeter in the system in the range of 1.8 to 4.0 kGy.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • How do Uncertainties in Atomic Parameters Influence Theoretical
           Predictions of X-Ray Production Cross Sections By Proton Impact'

    • Authors: J Miranda
      Abstract: The emission of characteristic X-rays induced by proton impact is a phenomenon known since the first half of the 20th century. Its more widely known application is the analytical technique Particle Induced X-ray Emission (PIXE). Several models have been developed to calculate, first, ionization cross sections and then the subsequent X-ray production cross sections. However, to carry out the comparisons of these predictions with experimental data it is necessary to use atomic parameters databases (fluorescence yields, Coster-Kronig transition probabilities, emission rates) that also have experimental uncertainties. In this work it is demonstrated how these values do not allow to decide which model describes more accurately the cross sections, due to a final “theoretical uncertainty” obtained through the propagation of the original uncertainties.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Stability of Glycine in Saline Solutions Exposed to Ionizing Radiation

    • Authors: Laura Patricia Cruz-Cruz; Alicia Negrón-Mendoza, Alejandro Heredia-Barbero
      Abstract: The stability of biologically important molecules, such as amino acids, being subjected to highradiation fields is relevant for chemical evolution studies. Bodies of water were very important in the primitive Earth. In these bodies, the presence of dissolved salts, together with organic molecules, could influence the behavior of the systems in prebiotic environments.
      The objective of this work is to examine the influence of sodium chloride on the stability of the amino acid glycine when subjected to high radiation doses. The analysis of the irradiated samples was followed by HPLC coupled with a UV-VIS detector. The results show that glycine in aqueous solutions (without oxygen) decomposed around 90% at a dose of 91 kGy. In the presence of salts, up to 80% of the amino acid was recovered at the same dose. Laboratory simulations demonstrate a protective role for sodium chloride (specifically the chloride ion) to glycine against an external source of ionizing radiation.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Analysis of Indoor Radon Distribution Within a Room By Means of
           Computational Fluid Dynamics (CFD) Simulation

    • Authors: A. Lima Flores; R. Palomino-Merino, V.M. Castano, G. Espinosa
      Abstract: Radon gas is recognized by international organizations such as the United States Environmental Protection Agency (US-EPA) as the main contributor of radiation environmental to which human beings are exposed. Therefore, the evaluation of indoor radon concentration is a matter of public interest. The emanation and the income of the gas inside a room will generate a negative impact on the quality of the air when the place is not properly ventilated. Understanding how this gas will be distributed inside the room will allow to predict the spatial and temporal variations of radon levels and identify these parameters will provide important information that researchers can be used for calculate radiation dose exposure. Consequently, this studies can prevent a health risk for the people that live or work within the room. Currently, several researchers use the technique called Computational Fluid Dynamics (CFD) to simulate the distribution of gas radon, making use of the various commercial programs that exist in the market. In this work, three simulations were developed in rooms that have a similar geometry but different dimensions, in order to observe how the gas is distributed inside a closed space and to analyze how this distribution varies when the volume of the place is increased. The results show that as the volume of the site increases the radon is mitigated more rapidly and therefore has lower levels of concentration of this gas, as long as the level of radon emanation is kept constant.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Stability of Pyruvic Acid Adsorbed Onto Clays and Exposed to Ionizing
           Radiation: Relevance in Chemical Evolution

    • Authors: R. C Acosta-Fernández; A. Heredia-Barbero, A. Negrón-Mendoza
      Abstract: Chemical evolution studies focus on the synthesis and stability of organic molecules during various transformative physicochemical processes. Gaining insight into the possible mechanisms behind these processes requires the use of various energy sources and catalysts that can produce such transformations. In this work, ionizing radiation (60Co) was used as a source of energy, and two clays with different exchangeable cations-sodium and iron (III)-were combined with pyruvic acid, a key alpha keto acid in metabolism. The samples of pyruvic acid were prepared at a concentration of 0.01 M; then, adsorption experiments were carried out by combining sodium or iron montmorillonite at different times. The amount that adsorbed onto iron montmorillonite was greater than the amount that adsorbed onto sodium montmorillonite. Samples of alpha keto acid at the same concentration were irradiated-in the absence of clay-at 0 to 146.1 kGy and at two pHs (6.7 and 2.0). The suspended samples with sodium and iron clay were then irradiated at the same doses. The results show that keto acid decomposes more quickly at more acidic pHs. The main reaction to irradiation without clay involves the dimerization of pyruvic acid, and 2,3-dimethyltartaric acid is the majority product. When irradiated in the presence of clay, the main reaction is decarboxylation, and acetic acid is the majority product. The exchangeable cation type modifies the interactions between the organic molecule and the solid phase. The percentage of recovered pyruvic acid is higher for iron montmorillonite than for sodium montmorillonite.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • PADC-NTM Applied in 7Li+Pb at 31 MeV Reaction Products Study

    • Authors: M. Cinausero; A. M. Sajo-Castelli, L. Sajo-Bohus, J. Palfalvi, G. Espinosa
      Abstract: Passive nuclear track methodology (NTM) is applied to study charged particles products of the reaction 7Li+Pb at ~ 31 MeV. It is a contribution to the 8pLP Project (LNL-INFN-Italy) in where we show an alternative approach to register charged particle from reaction fragments by PADC detection. The main advantage is that the passive system integrates data over the whole experiment and has its importance for low rate reaction processes. Reaction products as well as scattered beam particles are determined from track shape analysis. Some limitations are inherent to NTM since a priori knowledge is required to correlate track size distribution given by each type of particle emerging from the target. Results show that the passive technique gives useful information when applied in reaction data interpretation for a relatively large range of particle types.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Radiation Induced Reactions of Succinic Acid in Aqueous Solution: An
           Agent-Based Model

    • Authors: Ana Leonor Rivera; Sergio Ramos-Beltran, Alicia Negrón-Mendoza
      Abstract: An approach to studying the formation of critical bio-organic compounds in the early Earth is to simulate in the laboratory possible processes that may occur in primitive scenarios. In this context, it can be studied the evolution of succinic acid in an aqueous media exposed to gamma radiation, as starting material produced more complex prebiotic molecules. To describe the products generated by the interaction of the different elements under radiation, there is a mathematical model that considers chemical reactions as nonlinear ordinary differential equations based on the mass balance of all the species, that has been implemented here by an agent-based model. In this simulation, each chemical species involved is considered as an agent that can interact with other species with known reaction rates, and the radiation is taken as a factor that promotes product formation. The results from the agentbased model are compared with the molar concentrations of succinic acid, and its products obtained in the lab. Simulation shows the exponential decomposition of succinic acid due to gamma radiation at room temperature in agreement with the laboratory model.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Effect of Laser Radiation on Biomolecules

    • Authors: E. Prieto; L. X. Hallado, A. Guerrero, I. Álvarez, C. Cisneros
      Abstract: Time of flight laser photoionization has been used to study the response of some molecules of biological interest under laser radiation. One of the questions of great interest today is the effect of radiation on DNA and RNA molecules. Damage to these molecules can be caused directly by radiation or indirectly by secondary electrons created by radiation. As response of the radiation field fragmentation process can occur producing different ions with kinetic energies of a few electron volts. In this paper we present the results of the interaction of 355nm laser with the nitrogen bases adenine(A) and uracil(U) using time-of-flight spectrometry and the comparison of experimental results on the effects of laser radiation in (A) and (U) belonging to two different ring groups, purines and pyrimidines respectively,
      which are linked to form the AU pair of the RNA.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • A Data Mining Perspective of XRF Elemental Analysis from Pueblo
           People’s Pottery

    • Authors: M. Castro-Colin; E. Ramirez-Homs, J. A. López
      Abstract: Hierarchical clustering was used to identify elemental signatures in artifacts attributed to the Pueblo peoples. The artifacts in this study are pottery samples found at different sites in the state of New Mexico, USA. Three methods were applied: complete, average, and Ward. Their corresponding cophenetic correlation coefficients were used to contrast the three methods. Elemental characterization was only based on X-ray fluorescence excitation from a portable spectrometer with the silver anode. The elemental correlations here disclosed by data mining techniques are expected to guide further archaeological studies and assist experts in the assessment of provenance and historical ethnographic studies. XRF elemental analysis
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Behavior of Poly-A onto Kaolin

    • Authors: María Guadalupe Torres-Duque; Claudia Camargo-Raya, Alicia Negrón-Mendoza, Sergio Ramos-Bernal
      Abstract: A combination of geochemical variables is necessary to explain the origin of life on Earth. Thus, in this work the sorption of Poly-A on a clay mineral (kaolinite) was studied to get an insight about the sorption capacity at different times and pH values, as well as to confirm the capabilities of the clay to protect the sorbate from an external source of ionizing radiation. Poly-A presented a high percentage of sorption in the clay, especially in acidic environments, and this percentage sharply decrease in alkaline media. On the other hand, Poly-A’s recovery was higher in the system with clay, confirming its protection role.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Preliminary Measurements of Be-10/Be-7 Ratio in Rainwater for Atmospheric
           Transport Analysis

    • Authors: K. de los Ríos; C. Méndez-García, L. Acosta, R. García-Martínez, M. A. Martínez-Carrillo, M. E. Ortiz
      Abstract: The meteoric cosmogenic beryllium has been used as an essential geophysical tracer in the analysis of atmospheric flows and erosion soils since 1960. The first measurements Be-7 and Be-10 concentrations in rainwater from Mexico, have been carried out by using gamma decay spectroscopy and AMS techniques, respectively for each isotope. With this it was possible to report a preliminar value for the Be-10/Be-7 isotopic ratio in such environmental samples. The present work described preliminary results related to rainwater collected at mountain and metropolitan areas. Results are compared with predictions and previous measurements for both radioisotopes, observing a very sensible behavior particularly for the case of Be-7 activities.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Analysis of DDM into Gamma Radiation

    • Authors: C. Arellano-Celiz; A. Avilez-López, J. E. Barradas-Guevara, O. Félix-Beltrán, F. González-Canales
      Abstract: We are interested in the purpose of a dipolar fermionic particle as a viable candidate of Dark Matter (DDM). Then, we study the annihilation of dark matter into photons, considering it as a neutral particle with non-vanishing magnetic (M) and electric (D) dipolar moments. The total annihilation cross section σ(χchi bar → γgamma bar) is computed by starting from a general form of coupling χchi barγ  in a framework beyond to Standard Model (BSM). We found that candidates with O(mχ )∽102GeV, D≈10−16 e cm are required in order to satisfy the current cosmic relic density.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Characterizing a Mini Gamma Detector

    • Authors: E. Márquez-Quintos; E. Moreno-Barbosa, J. E. Espinosa, Benito de Celis Alonso, Margarita Amaro Aranda, R. Palomino Merino
      Abstract: There are several types of gamma radiation detectors, which have different characteristics depending on its use. We designed and instrumented a gamma detector for low energies of a small and portable size to obtain spectrum from radioactive sources and from that analyze each spectrum. This instrument basically consists of a scintillator crystal coupled to a SiPM this in turn coupled to a PCB card designed with capacitors and resistors for a better signal, a voltage source of 29 volts. For signal acquisition the system must be connected to an oscilloscope this in turn is controlled by a script developed in Python. For the calibration radioactive isotopes with the same dimensions were used, caesium-137 (Cs-137), cobalto-60 (Co-60), sodium-22 (Na-22) and manganese-54 (Mn-54) as gamma ray emission.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Study of the Erosion of Copper by Hot Plasma

    • Authors: R. S. Monzamodeth; B. Campillo
      Abstract: An exhaustive study of the erosion process of a copper cathode exposed to a hot plasma column of 2kJ of energy (T≈0.5-2.0keV) and high electron density (n≈1019-1022cm3) was made, as well as, the radiation field of charged and neutral particles. The characterization of the cumulative damage generated by the plasma/cathode interaction was made by the use of metallographic techniques, scanning electron microscopy (SEM) and by the analysis of mechanical properties. Damage accumulation produced by the impacts of deuterium plasma discharge created in the copper electrode a deep cavity similar to a crater, modifying the morphology of the surface and below it. The microhardness Vickers test was carried out making indentations from the final part of the cavity to cover 1 cm with indentations every 200 μm. Different areas of hardening were observed, the profile suggests a hardening/recovery front and simultaneous recrystallization in the sample, phenomenon associated with the heating/cooling cycles to which the copper cathode is subjected. Images were captured by SEM at different distances from the center of the surface. The region that showed involvement at the macro level corresponds to 2/3 of the radius of the sample from the center to the outside. These phenomena studied are important to understand the nature of the plasma/wall interaction in any fusion device.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Study of CT Images Processing with the Implementation of MLEM Algorithm
           using CUDA on NVIDIA’S GPU Framework

    • Authors: T. A. Valencia-Pérez; J. M. Hernández-López, E. Moreno-Barbosa, B. de Celis-Alonso
      Abstract: In medicine, the acquisition process in Computed Tomography Images (CT) is obtained by a reconstruction algorithm. The classical method for image reconstruction is the Filtered Back Projection (FBP). This method is fast and simple but does not use any statistical information about the measurements. The appearance of artifacts and its low spatial resolution in reconstructed images must be considered. Furthermore, the FBP requires of optimal conditions of the projections and complete sets of data. In this paper a methodology to accelerate acquisition process for CT based on the Maximum Likelihood Estimation Method (MLEM) algorithm is presented. This statistical iterative reconstruction algorithm uses a GPU Programming Paradigms and was compared with sequential algorithms in which the reconstruction time was reduced by up to 3 orders of magnitude while preserving image quality. Furthermore, they showed a good performance when compared with reconstruction methods provided by commercial software. The system, which would consist exclusively of a commercial laptop and GPU could be used as a fast, portable, simple and cheap image reconstruction platform in the future.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Development and Validation of an X-ray Imaging Detector for Digital
           Radiography at Low Resolution

    • Authors: Abdiel Ramírez Reyes; Gerardo Herrera Corral, Elsa Ordoñez Casanova, Héctor Alejandro Trejo Mandujano, Uzziel Caldiño Herrera
      Abstract: Digital X-ray detectors are required in different sciences and applications, however many high quality devices are expensive although high-resolution images are not always required. We present an easy way to build a detector capable of forming X-ray digital images and video with a very large area (18×18 cm2). The detector is formed by three main components: scintillator, optics lenses and CCD sensor. Basically, the device converts the X-rays into visible light which is then collected by the CCD sensor. The scintillator is Gadox type, from Carestream®, 18×18 cm2, regular type, lambda 547 nm. The optics lenses are generic, with manual focus and widely visual field. The CCD sensor has a size of 1/3″, 752 × 582 pixels, monochrome, 20 FPS, 12 bits ADC and pixel size of 3.8 μm. With the built detector and an X-ray source, we formed an X-ray imaging detection system to generate digital radiographs of biological or inert objects-examples are given-, as well as real-time X-ray video. Additionally, the spatial resolution limit was measured in terms of Modulation Transfer Function by the method of opaque edge from a lead sheet with a result of 1.1 Lp/mm. Finally using a filter, the focal spot of the X-ray source is measured, resulting in a diameter of 0.9 mm (FWHM).
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Structural Variations Induced by Temperature Changes in Rotavirus VP6
           Protein Immersed in an Electric Field and Their Effects on Epitopes of The
           Region 300-396

    • Authors: C. Peña-Negrete; M.A. Fuentes-Acosta, J. Mulia, L.A. Mandujano-Rosas, D. Osorio-González
      Abstract: Rotavirus diarrhea is an infectious intestinal disease that causes about 215 thousand deaths annually in infants under five years old. This virus is formed by three layers of concentric proteins that envelop its genome, from which VP6 structural protein is the most conserved among rotavirus serotypes and an excellent vaccine candidate. Recent studies have shown that structural proteins are susceptible to losing their biological function when their conformation is modified by moderate temperature increments, and in the case of VP6, its antigen efficiency decreases. We performed an in silicoanalysis to identify the structural variations in the epitopes 301-315, 357-366, and 376-384 of the rotavirus VP6 protein -in a hydrated medium- when the temperature is increased from 310 K to 322 K. In the latter state, we applied an electric field equivalent to a low energy laser pulse and calculated the fluctuations per amino acid residue. We identified that the region 301-315 has greater flexibility and density of negative electrical charge; nevertheless, at 322 K it experiences a sudden change of secondary structure that could decrease its efficiency as an antigenic determinant. The applied electric field induces electrical neutrality in the region 357-366, whereas in 376-384 inverts the charge, implying that temperature changes in the range 310 K-322 K are a factor that promotes thermoelectric effects in the VP6 protein epitopes in the region 300-396.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Analysis of the Radon-222 Concentration and Physical-chemical Quality, in
           Drinking Water of Taxco, Guerrero

    • Authors: A. H. Ramírez; O. Talavera, S. Souto, J. I. Golzarri, G. Espinosa
      Abstract: In this work the determination of radon gas (222Rn) and the characterization of chemical elements in drinking water of the city Taxco was carried out. Ingesting or inhaling a small number of radionuclides, as well as water of poor chemical quality, can become a potential public health problem. We are collecting 8 samples of water from a spring, physicochemical parameters were measured in field on different days of the dry season. Measurements of 222Rn were performed in the laboratory with an AlphaGUARD equipment. The chemical quality was analyzed in laboratory too by means of mayor and minor ions, by volumetry and colorimetry. The sodium was determined by Flama Atomic Absorption Spectroscopy (FAAS). Trace elements were analyzed by were determined by Atomic Emission Spectroscopy with Plasma Coupled by Induction (ICP-AES). The concentrations of 222Rn present an average of 22.06 ± 2.52 BqL-1. The results obtained from the main ions and field parameters show a type of diluted sodium-calcium-bicarbonate water. The trace elements present are very small and not exceed the limit of quantification. Radon gas is produced by the igneous rock that is the top of the stratigraphic column, of the hydric recharge. Rainwater when descending through the fractures is impregnated with 222Rn gas and accumulated in the underlying rock that has sufficient porosity to accumulate water and gas in the Chacualco´s spring.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
  • Measurement of Content of 226Ra in Drinking Water From Some States of
           Mexican Republic by Liquid Scintillation Method

    • Authors: A. Ángeles; E. Quintero, I. Gaso, C. P. Zepeda, T. Palma, P. V. Rojas
      Abstract: To assess the quality of drinking water in respect to the content of radioactivity, usually is carried out an screening program in the locations of interest, that program consist in pick representative samples of drinking water from the wells in that locations, water samples are analyzed to measuring the gross alpha/beta radioactivity by a low background proportional counter or a liquid scintillation system. When some sample exceeds the normative limit then it must be known which radionuclides are in that sample. Expected radionuclides in water are the NORM (normal occurring radioactive material) from the natural radioactive chains. 226Ra is frequently present in drinking water and is one of most important radionuclide because its “radiotoxicity”, the WHO [World Health Organization, Guidelines for drinking-water Quality, (2016)] recommends a reference level for 226Ra of 1 Bq/L (the dose coefficient for 226Ra is 2.8 x 10-7 Sv/Bq). From a national program of drinking water screening in the Mexican Republic, the samples that exceeded the national normative limits were picked again in the same well and analyzed by LS (liquid Scintillation), using the method of two phases with a not water miscible scintillator cocktail. Results of concentrations of 226Ra from drinking water are presented. In general the content of 226Ra in drinking water samples was lower that the guide values recommended for the WHO.
      PubDate: Fri, 28 Feb 2020 00:00:00 +053
       
 
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