共查询到20条相似文献,搜索用时 31 毫秒
1.
M. E. Medhat L. F. Pires R. C. J. Arthur 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(3):1105-1112
In the present work the total mass attenuation coefficients (μ/ρ) for some soils collected from the Southeast and South of Brazil were measured at 59.5 (241Am) and 661.6 keV (137Cs) photon energies. The experimental values of the soils μ/ρ were compared with XCOM program calculations and GEANT4 Monte Carlo simulations. Total atomic and electronic cross-sections, effective atomic and electron numbers of all soil samples were calculated in a wide energy range (1 keV–100 GeV). The values of these parameters have been found to vary with photon energy and chemical composition of the soil. The variations of these parameters with energy are shown graphically for total photon interactions. The results showed that loamy soils have low photon attenuation parameters than clayey ones for the region of 59.5 keV. 相似文献
2.
The radiation attenuation coefficients ??/?? (cm2?g?1) for concrete and cement samples that used for experimental studies by other researchers were determined by Monte Carlo calculations at 59.5, 80, 356, 661.6, 1173.2 and 1332.5?keV photon energies. The simulated results of attenuation coefficients were compared with the reported experimental data for the same samples and a good agreement has been observed. The intent of this research was to develop a Monte Carlo program useful for various absorbers and energies. The variation of the attenuation coefficient with photon energy has also been investigated for these samples. 相似文献
3.
V. Bulovič J. Krtil F. Sus Z. Maksimovič E. Klosová 《Journal of Radioanalytical and Nuclear Chemistry》1979,51(1):153-160
Determination of106Ru,134Cs,137Cs and144Ce in samples of irradiated fuel from the Czechoslovak atomic power station Al is described. The determination is based on
gamma-spectrum analysis. The analysis was performed using a Ge(Li) semiconductor detector; for the determination of the isotope
mentioned the lines in the energy interval from 400 to 1300 keV were used. The analyses of both dissolved and non-dissolved
samples of the fuel were performed. The results of the determinations and their comparison are given in detail. 相似文献
4.
The probabilities for vacancy transfer from the K to the L shell (ηKL), have been calculated for eleven high atomic number elements using the measured K and L shells X-ray production cross-sections. The targets were excited by 123.6 keV photon from a 57Co annular radioactive source. K and L X-rays emitted by samples were counted with a Si(Li) detector. The measured values of ηKL were compared with the theoretical values and our early papers. 相似文献
5.
A. Aksoy 《Journal of Radioanalytical and Nuclear Chemistry》1993,169(2):463-469
The absolute total and full-energy peak (FEP) efficiencies of a high purity germanium (HPGe) photon detector are measured in the energy range from 40 keV to 1500 keV. The functional parameters are fitted to the calibration points from 14 long-lived standard sources (129I,241Am,109Cd,57Co,139Ce,137Cs,54Mn,65Zn,60Co,22Na,133Ba,152Eu,154Eu and166mHo) within an accuracy better than the quoted uncertainty of the calibration sources. The efficiencies in far and close geometries are compared. 相似文献
6.
M. Šiljegovi? Z.M. Ka?arevi?-Popovi? N. Bibi? Z.M. Jovanovi? S. Maleti? M. Stchakovsky A.N. Krklješ 《Radiation Physics and Chemistry》2011,80(12):1378-1385
Fluorinated ethylene propylene (FEP) and tetrafluoroethylene–perfluoro(alkoxy vinyl ether) (PFA) copolymer films were irradiated in vacuum with 60 keV C4+ and N4+ ions to fluences ranging from 1.0×1012 to 5.0×1015 cm−2. Changes in optical and dielectric properties were analyzed by spectroscopic ellipsometry and ultraviolet–visible (UV–vis), Raman and dielectric relaxation spectroscopies. Direct and indirect energy band gap values were determined from the absorption edge in the 200–800 nm region using Tauc's relation. The values of the direct energy gap have been found to be greater than the corresponding values of the indirect energy gap. Significant changes in the index of refraction, and β and γ dielectric relaxations were observed in the case of N4+ irradiated FEP and PFA samples. 相似文献
7.
V. K. Ivanov J. B. West G. F. Gribakin A. A. Gribakina 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1994,29(2):109-114
We present calculations of total and partial photoionisation cross sections for the 2s, 2p and 3s subshells of Mg+ from their ionisation thresholds up to a photon energy of 220 eV. Photoelectron angular distribution parameters are also calculated for the 2p subshell. Oscillator strengths are given for discrete structure, and calculated energy levels compared with experimental values. The significance of electron correlations and two electron excitation for this atomic ion is discussed. 相似文献
8.
Effective atomic numbers, effective electron densities for photon mass energy absorption and kerma values of soft tissue and some thermoluminescence dosimeter containing boron are calculated in the energy range from 1 keV to 20 MeV. It is investigated that the variation of effective atomic numbers, effective electron densities and kerma with energy. The TL dosimeters studied are compared with the soft tissue for calculated values. In addition, dopant effect on the effective atomic numbers and electron densities for photon mass energy absorption and kerma values of the TL dosimeter containing boron is presented. Effect of the concentrations of the element H on effective electron density of the soft tissue is discussed. 相似文献
9.
A. G. C. Nair A. V. R. Reddy R. N. Acharya P. P. Burte S. B. Manohar 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(3):877-881
A chemical neutron activation analysis method to determine trace amounts of palladium present in the uranium ores has been
developed. Palladium was concentrated on an anionic exchanger to purify from large amounts of uranium, iron and copper that
were present in the ore. The resin in which Pd was adsorbed was neutron irradiated and the activation product109Pd was assayed through its daughter109mAg by low energy photon spectrometry to estimate palladium. Both the 88 keV gamma-line and the 22 keV X-ray line (arising
out of the internal transition of109mAg) were used to arrive at the concentration values by a standard comparison technique. A thin window Si(Li) detector and
an HPGe detector were used for the radioactive assay. Detection limits and the advantage of using the X-ray line of Ag over
that of the gamma-line were discussed. An absolute detection limit of 0.12·10−9 g could be arrived at by the use of the 22.10 keV X-ray line in an interference-free condition. 相似文献
10.
《Spectrochimica Acta Part B: Atomic Spectroscopy》1997,52(8):1167-1171
Chemical effect on the photon induced L X-ray fluorescence cross-sections (σLα, σLβ and σLγ) for Hg, Pb and Bi compounds were investigated. The samples were excited by gamma rays with energy 59.5 keV from 241Am radioisotope source. L X-rays emitted by samples were counted by a Si(Li) detector with resolution 160 eV at 5.9 keV. We observed chemical effect on the photon induced L X-ray fluorescence cross-sections (σLα, σLβ and σLγ) for Hg, Pb and Bi compounds. Our values were compared with calculated theoretical values. 相似文献
11.
S. Chhillar R. Acharya R. V. Pai S. Sodaye S. K. Mukerjee P. K. Pujari 《Journal of Radioanalytical and Nuclear Chemistry》2012,293(1):437-441
A particle induced gamma-ray emission method using proton beam in conjunction with in situ current normalization approach was standardized for non-destructive determination of low Z element lithium and was applied for quantification of Li in lithium doped neodymium dititanate (Nd2Ti2O7) ceramic sample. Thick pellets of heat treated samples, their precursors and Li standards were prepared separately by homogeneously mixing with cellulose and fixed amount of F used for in situ current normalization. For validation of the method, four synthetic samples were also analyzed. Samples and standards were irradiated with 4?MeV proton beam (~5?nA current) from folded tandem ion accelerator (FOTIA) BARC, Mumbai. Characteristic ??-rays of 478?keV from 7Li to 197?keV from 19F were measured by high resolution ??-ray spectrometry. The Li concentrations determined in the six samples were in the range of 0.29?C0.85?wt%. The Li contents in heat treated samples gave the idea about loss of Li compared to their precursors. 相似文献
12.
D. G. Mishra R. Acharya K. K. Swain R. M. Joshi V. M. Joshi P. C. Verma A. G. Hegde A. V. R. Reddy 《Journal of Radioanalytical and Nuclear Chemistry》2012,294(3):333-336
Thorium along with its daughter products present in the soil is one of the major contributors to the external gamma dose in the environment. To establish the dose levels, quantification of thorium contents in soil samples is very important. As a part of pre-operational environmental radiological surveillance, a total of 23 soil and six sand samples were collected from different locations around the proposed nuclear power plant site of Jaitapur, Maharashtra. Thorium concentrations in these samples were determined by instrumental neutron activation analysis (INAA). Samples were irradiated with neutrons in Apsara reactor at a neutron flux of?~5?×?1011 cm?2 s?1 and radioactive assay was carried out using high resolution gamma ray spectrometry. Relative method of INAA was used for quantification of thorium utilizing 311.9?keV gamma ray of 233Pa, the daughter product of 233Th. The concentrations of thorium in the soil and sand samples were in the ranges of 4.0?C18.8 and 1.2?C6.2?mg?kg?1 respectively. 相似文献
13.
Theoretical K-shell photoionization and K X-ray fluorescence (K XRF) cross sections have been fitted empirically in polynomials of photon energy E and atomic number Z. This has been used to develop a computer code KCSPIF to generate K-shell photo-ionization and K XRF cross-sections for any element in the range 5≤Z≤95 and for photon energies, above K-edge–1500 keV, when only the atomic number and photon energy are supplied as the input. 相似文献
14.
E. Cengiz V. Aylıkcı N. Kaya G. Apaydın E. Tıraşoğlu 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(1):89-96
In this study, the chemical effects on σKi
(i = α, β), σLα cross sections, Kβ/Kα X-ray intensity ratios and vacancy transfer probabilities from K to L (η
KL) for pure Nb and Nb compounds were investigated. The samples were excited by 59.5 keV γ-rays from 241Am and 5.96 keV photon energy from a 55Fe annular radioactive sources. K and L X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution
of 150 eV at 5.9 keV. While it was observed that the chemical bonding had an effect on the σKβ, σLα cross sections and Kβ/Kα X-ray intensity ratios for compounds, it was almost negligible for σKα cross section because Kα transitions (2P3/2,1/2→1S1/2) occurred in inner shells. It is well known that interactions between central element atom and ligands come into existence
in valence state, so outer energy levels are sensitive to the chemical environment. The experimental values of σKα cross section and η
KL are in good agreement with theoretically calculated and other experimental values of pure niobium, but the experimental values
of the σKβ, σLα cross sections and Kβ/Kα X-ray intensity ratios have differences for some compounds because valence electrons have different bond distances and binding
energies in different compounds. 相似文献
15.
We present a review of our recent measurements of large angle elastic and inelastic scattering differential cross-sections in the photon energy range 14–88 keV (momentum transfer ranging 1.135 to 6.310 Å−1 covering large number of elements in the atomic region Z=1–92, with special emphasis on the elements having K/Li shell/subshell binding energy in the vicinity of the incident photon energy. These measurements were performed using energy dispersive X-ray fluorescence (EDXRF) setup involving radioisotope as a photon source and a solid-state photon detector arranged in an annular geometry. The measured scattering differential cross-sections were compared with the theoretical values based on the state-of-art relativistic second order S-matrix calculations and those based on the form factor approximations in order to check their reliability. The KL and KM resonant Raman scattering (RRS) at 59.54 keV incident photon energy was also investigated for some heavy elements. 相似文献
16.
T. Hashimoto H. Saitoh H. Suzuki S. tonouchi T. Sotobayashi 《Journal of Radioanalytical and Nuclear Chemistry》1985,94(6):373-380
A simple and reliable method has been developed for the evaluation of radioactive disequilibrium state in fossil bones. The fossil bone samples were irradiated with an extremely low neutron fluence, together with a standard pitchblende prevailing the secular equilibrium among the uranium series. The239Np activity induced from238U in both samples were adjusted to be gamma-ray spectrometrically nearly equivalent to the naturally occurring radioactivities by controlling the neutron flux and cooling time. Using single gamma-ray spectrometry of the irradiated samples, the determination of214Bi/238U in a fossil bone was carried out by comparing the photopeak ratios of214Bi /609 keV/ and239Np /278 keV/ instead of238U with the same ratios from the pitchblende standard sample. 相似文献
17.
Tran Duc Thiep Truong Thi An Nguyen Tuan Khai Phan Viet Cuong Nguyen The Vinh A. G. Belov O. D. Maslov 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(3):1035-1042
We have determined the isomeric ratios in 74Se(γ, n)73m,gSe and 82Se(γ, n)81m,gSe photonuclear reactions of natural Selenium induced by bremsstrahlungs with end-point energies in the giant dipole resonance
region. The investigated samples were irradiated at electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear
Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The gamma spectra of the samples irradiated were measured with
spectroscopic system consisting of 8,192 channel analyzer and high-energy resolution (180 keV at gamma ray 1,332 keV of 60Co) HP(Ge) semiconductor detector Canberra. The GENIE2000 (Canberra) computer program was used for data processing. The results
were discussed and compared with those of other authors. 相似文献
18.
M. Ertugrul 《Journal of Radioanalytical and Nuclear Chemistry》1997,219(1):111-114
Experimental total attenuation coefficients of carbon in the photon energy range 4.5–60 keV have been measured. The total attenuation cross section of C rapidly decreased with energy in the range of 4.5–10 keV. The measured values are in agreement with the theoretical values. 相似文献
19.
The photopeak efficiency, peak to valley ratio and energy resolution of a 3×3×1 mm3 CdTe detector were determined experimentally for 13–1333 keV photon energy by using polyester coated radioisotopes 241Am, 22Na, 54Mn, 57Co, 60Co, 109Cd, 137Cs and 133Ba. The data were analyzed by using PX4 from Amptek. The experimental values were fitted to an analytical function of photon energy, and an agreement was observed for the entire range of the studied energies. The results have shown that the CdTe detector has a high performance due to both the improved charge collection efficiency comparable with that of SI GaAs detectors (Vittone et al., 1999), and the low leakage current. Also, CdTe detector is very attractive for field application as it works at room temperature. 相似文献
20.
T. A. de Vol A. H. Ringberg R. A. de wberry 《Journal of Radioanalytical and Nuclear Chemistry》2002,254(1):71-79
A combination alpha and conversion electron spectrometer was developed to quantify 239Pu/240Pu and 238Pu/241Am isotopic ratios of plated sources. The spectrometer was constructed with a commercially available low noise passivated ion-implanted planar silicon (PIPS) detector that was cooled to 77 K with liquid nitrogen. The combination spectrometer was used to quantify alpha-particles, conversion electrons, gamma-rays and X-rays associated with the decay of various plutonium isotopes and 241Am. Two amplifiers operated in parallel with different gains allowed for simultaneous acquisition of the lower energy region (21-60 keV) for internal conversion electrons, gamma-rays and X-rays, and the higher energy region (5050 keV-5550 keV) for alpha-particles. Energy resolutions of 2.2 keV FWHM (full-width at half maximum) for the 38.7 keV M conversion electrons and 11.2 keV for the 5499.2 keV alpha-particles from 238Pu were measured. The energy resolution combined with a spectral deconvolution method was sufficient to be able to quantify the radioactivity using the alpha-spectra as well as the electron spectra; however, quantification of the radioactivity using the internal conversion electron spectra was more problematic because of the presence of X-rays, gamma-rays, Compton scatter electrons and the number of electron peaks present. Deconvolution of the alpha-spectra yielded 239Pu and 240Pu activities (as % of total Pu activity), which differed from expected values by -3.0% to 5.4%. Deconvolution of an internal conversion electron spectrum of a high 239Pu and low 241Am activity sample yielded 239Pu and 240Pu activities, which differed by -17.1 and -35.5% relative to the alpha-measurements, respectively. Determination of the Pu activity using the electron spectra was more problematic in samples where the 241Am activity dominated. Determination of 238Pu and 241Am activity by the electron spectroscopy data was also obtained and compared with the alpha-spectroscopy results. Theoretical investigation of the removal of 241Am or use of a 400 eV electron spectrometer indicated that the internal conversion electron spectra could be used to determine the 238Pu, 239Pu, 240Pu/241Am (when present) activity with and without spectral deconvolution, respectively. 相似文献