Journal of Nuclear Physics, Material Sciences, Radiation and Applications
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Energy Transfer Dye Laser Study of Influence of Various Coumarin Dyes on the Laser Performance of Rh590(Cl) Dye
Get PDFDifferent coumarin dyes(C440, C460, C480, C485, C500 and C540A) are mixed with Rh590(Cl) in ethanol. The effect of coumarin dyes and their concentration on the laser gain properties and photostabilities of Rh590(Cl) is studied and discussed by investigating the gain characteristics at various concentrations and pump powers of N2–laser. It is found that for C480 and C540A dyes at optimized concentration, most of the absorbed pump power is transferred to Rh590(Cl) as a useful pump power. The gain characteristics of Rh590(Cl)are found to be changed due to change in the fluorescence lifetime. The mechanism responsible for the improvement in the laser performance and gain characteristics of Rh590(Cl) resulted from the energy transfer from these coumarin dyes. This improvement in the laser efficiency of Rh590(Cl) varied sharply depending upon the kind of coumarin dye. The theoretical calculations are also done to find the total transfer efficiency at various donor concentrations to identify the appropriate energy transfer mechanism responsible for gain enhancement in Rh590(Cl) dye. These calculations take into account the contribution due to both radiative and non radiative energy transfer. In these dye mixtures the energy transfer excitation was found to overcome the inner filter effect and other losses such as photoquenching. The concentration dependence of peak gain and the lasing wavelengths of ETDL have been studied. The experimental results indicate that the dominant mechanism responsible for the efficient excitation transfer in these mixtures is of non radiative nature due to long range dipole-dipole interaction. A broader tunable range is also provided by energy transfer
EDXRF Analysis of Some Fungal Species for the Uptake Capacity of 28Ni, 48Cd, and 82Pb Metal Ions From Aqueous Solution
Get PDFIn this paper, Energy Dispersive X-ray Fluorescence (EDXRF) analysis of eight fungi species, namely, Aspergillus niger, Aspergillus terreus, Trichoderma longibrachiatum, Trichoderma fasciculatum, Penicillin Janthinellum, Aspergillus awamori, Phanerochaete chrysosporium, and Rhizopus arrhizus for the uptake capacity of 28Ni, 48Cd, and 82Pb metals ions from aqueous solution have been reported. Fungal samples having superior ion removal capacity through bioaccumulation and biosorption were obtained from sites contaminated with heavy metals. The detection limit in EDXRF set up was improved considerably using selective absorbers in the path of incident photons from the X-ray tube to reduce the background in the desired energy region. It has been observed that all fungi species under present study have greater affinity for 82Pb ions as compared to 28Ni and 48Cd metal ions. The Trichoderma longibrachiatum and Trichoderma fasciculatum fungi species were identified to be more efficient for removal of heavy metal ions from waste water. The measured uptake capacity of Trichoderma longibrachiatumfor 28Ni, 48Cd, and 82Pb ions from aqueous solution is 0.52 mg/g, 0.97 mg/g, and 6.4 mg/g, respectively, and for Trichoderma fasciculatum it is 0.43 mg/g, 0.79 mg/g, and 3.5 mg/g, respectively. This indicated the potential of these identified fungi species as biosorbent for removal of high metal ions from waste water and industrial effluents
Characterization of LR-115 Type 2 Detectors for Monitoring Indoor Radon 222: Determination of the Calibration Factor
Get PDFThe city of Lima, capital of Peru, has about 11 million inhabitants. Lima has no records about the indoor Radon 222 concentration levels in dwellings. Hereby, we are planning to register the indoor radon concentrations in Lima and in other cities of Peru in the next three years. First, we will determine the calibration factor for the detectors which will be used in our measurements. For this purpose, Solid State Nuclear Tracks Detectors of nitrocellulose nitrate (LR-115 type 2) were used.The calibration process using a Radium 226 source was described to obtain the calibration factor. Linear response in tracks number was found in relation with irradiation time and its stability after time at the calibration chamber
Proposal of a Novel Setup for Linac Monitoring Using a Specifically Designed Plastic Scintillator and a Spectrophotometer
Get PDFIn this work we report the design, implementation and results of an alternative monitoring system for a linear accelerator (LINAC) used in medical therapy. The system proposed consist in aslab of scintillator plastic with awavelength shifter fiberoptically coupled to collect the light generated,and a Spectrophotometer Ocean Optics USB4000 as analyzer. The control was made with two computers, one into the therapy room and another, using a VNC (Virtual Network Computer) and Ethernet wire, outside of the room in order to avoid radiation exposure. The LINAC dose range covered was 1, 2, 3, 4, 5, 10, 20, 30 and 40 Monitor Units (MU) with 6 and 18 MeV energy photons. The spectrum obtained was compared with the measures of the LINAC ionization camera used to calibrate it. The results obtained allowus to propose this device as an alternative method to monitor the LINAC performance
Revisiting Natural Radiation in Itacaré and Guarapari Beaches
Get PDFHuman beings are constantly exposed to several types of natural radiation. This paper aims to study the total external dose from northwestern Brazilian beach sands. The samples were collected at Prainha in Itacaré, Bahia, and Praia de AreiaPreta in Guarapari, Espírito Santo. Gamma spectrometry is a very useful technique to estimate the effective dose due to naturally occurring radionuclides, such as 40K and daughters of 238U and 232Th. In order to confirm the high activity present in these two regions, the effective dose due to each natural radionuclide was determined. Moreover, the Energy-Dispersive X-Ray Spectroscopy (EDS) microanalysis was used to characterize the soil composition and the minerals responsible for the high activity. In addition, the sand samples were separated in to magnetic and non-magnetic fractions in order to identify the contribution from each portion of the activity. Finally, the radionuclides and their dispersion in those places are consistent with previous studies, indicating effective doses above the world average that is between 0.3 mSv/year and 1.0 mSv/year
X-Ray Fluorescence Analysis of Fine Atmospheric Aerosols from a Site in Mexico City
Get PDFA study was performed in the Winter of the year 2015 in a Southwestern site in the MAMC (Ciudad Universitaria), collecting PM2.5 samples with a Mini Vol. As a part of wider study focused to fully characterize aerosols at this site, an X-ray Fluorescence (XRF) spectrometer (based on an Rh X-ray tube) built to analyze environmental samples, was used to characterize the sample set. A total of 16 elements (Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, and Pb) were detected in most samples and mean concentrations were calculated. Cluster analysis was also applied to the elemental concentrations to find possible correlations among the elements
Study of Neutron From a Dense Plasma Focus Paco Instrument by Means of Nuclear Tracks Detectors
Get PDFA most interesting feature of dense plasma foci is the acceleration of charge particle at energy in the range of MeV per nucleon. Using deuterium gas, this devices produce fusion D-D reactions, generation fast neutron pulses (~ 2.5 MeV). The device used in the present work is a Mather-type dense plasma focus, called PACO. It is a 2kJ device at 31 kV, with an oxygen-free copper anode, 50 mm long with 40 mm diameter. The coaxial cathode is formed by ten copper rods arranged in a squirrel cage configuration at a radius of 50 mm. The insulator in an annular Pyrex® tube located at the base of the anode. The energy store is provided by four 1 μF (40 kV, 40 nH) capacitors in parallel. The plasma focus was operated at 1.5 mb deuterium gas pressure. Neutron and accelerated particles are analyzed with material detectors (CR-39 Lantrack®) for different conditions. A detailed study is made of track diameters when the plastic is chemically etched with, 6N KOH at 60°C (±1) for 12
ZnS (Mn) Nanoparticles as Luminescent Centers for Siloxane Based Scintillators
Get PDFSynthesis of oleic acid stabilized ZnS nanocrystals activated with Mn is pursued. A hydrothermal method where high pressure and temperature are applied to control the nanocrystals growth is adopted. Capping the nanoparticle surface with oleic acid (OA) improved light output. Samples loaded with both the phosphor and the neutron sensitizer have been produced and tested in a preliminary test as alpha particle detectors and secondly as thermal neutron detectors. The results support further development for siloxane-based scintillator detectors employing ZnS (Mn) nanoparticles
Correlation Between Underground Radon Gas and Dormant Geological Faults
Get PDFThis work studies the concentration of radon in soil around a fault in the East Franklin Mountains in the El Paso area in West Texas. It is found that the in-soil production of radon is correlated to the existence of a fault even if it has not had any recorded activity in recent geological times. This adds to previous observations that link the production of radon to seismic activity, and seems to indicate that in non-active faults the radon production is due mainly to the radioactivity of the top soil and to the transport properties of the medium and not to deeper seismic activity. These results open the possibility of using in-soil radon gas concentrations as an examination tool of dormant faults
Cosmologically Strengthening Hydrogen Atom in Black Hole Universe
Get PDFWith reference to the earlier proposed black hole model of cosmology, the authors proposed a unified model mechanism for understanding the light emission mechanism in cosmologically ‘strengthening hydrogen atom’. In this proposed model, characteristic cosmic mass, characteristic nuclear charge radius, Avogadro number and possible quantum states of electron seem to play a major role. Throughout the cosmic evolution, Planck’s constant seems to be a constant whereas the currently believed ‘reduced Planck’s constant’ seems to be a cosmological decreasing variable.With this new proposal - Hubble’s redshift interpretation, Super novae dimming and currently believed cosmic acceleration can be reviewed at fundamental level and a correct model of cosmology can be confirmed