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1.
Tran Duc Thiep Truong Thi An Phan Viet Cuong Nguyen The Vinh 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(1):89-96
We have determined the isomeric ratios in 130Ba(γ, n)129m,gBa, 132Ba(γ, n)131m,gBa and 134Ba(γ, n)133m,gBa photonuclear reactions of natural barium 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 8192 channel analyzer and high-energy resolution (180 keV at gamma ray 1332 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
2.
Tran Duc Thiep Truong Thi An Phan Viet Cuong Nguyen The Vinh A. G. Belov 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(2):515-524
We have determined the isomeric ratios in 165Ho(γ, n)164m,gHo and 175Lu(γ, n)174m,gLu photonuclear reactions of natural holmium and lutetium induced by bremsstrahlungs with end-point energies in the giant
dipole resonance (GDR) 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 8192 channel analyzer and high-energy resolution (180 keV at gamma ray
1332 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
3.
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
4.
Tran Duc Thiep Truong Thi An Nguyen Tuan Khai Phan Viet Cuong Nguyen The Vinh 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(1):161-167
We have determined the isomeric ratio of 85m,gSr in photonuclear reactions of natural strontium induced by bremsstrahlungs with end-point energies in the giant dipole resonance
(GDR) region as well as the isomeric ratios of 85m,gSr and 84m,gRb produced at 65 MeV bremsstrahlung. In GDR region the target was irradiated at electron accelerator Microtron MT-25 of the
Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The target irradiation with 65 MeV
bremsstrahlung was performed at the linear electron accelerator of the Pohang Neutron Facility, Pohang, South Korea. The gamma
spectra of the samples irradiated in both cases were measured with spectroscopic systems consisting of 8192 channel analyzer
and high-energy resolution (180 keV at gamma ray 1332 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
5.
A. El Abd 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(2):321-326
The thermal neutron cross-sections and resonance integrals of the 186W (n,γ) 187W and 98Mo (n,γ) 99Mo reactions in the thermal and 1/E regions, respectively, of a thermal reactor neutron spectrum have been experimentally determined by the activation method
using 197Au (n,γ) 198Au reaction as a single comparator. The high purity natural W, Mo, and Zr foils; and Au wire diluted in aluminum, were irradiated
without Cd shield in two neutron irradiation sites, characterized with different values for the thermal-to-epithermal flux
ratios, f at the Second Egyptian Research Reactor (ETRR-2). The induced activities in the samples were measured by high-resolution
γ-ray spectrometry with a calibrated germanium detector. Thermal neutron cross-sections for 2200 m/s neutrons and resonance
integrals for the 186W (n,γ) 187W and 98Mo (n,γ) 99Mo reactions have been obtained relative to the reference values, σ0 = 98.65 ± 0.09 b and I
0 = 1500 ± 28 b for the 197Au (n,γ) 198Au reaction. The necessary correction factors for thermal neutron and resonance neutron self-shielding effects, and the epithermal
flux index (α) were taken into account in the determinations. The results obtained were: σ0 = 38.43 ± 0.4 b and I
0 = 502 ± 65 b for 186W (n,γ) 187W, and σ0 = 0.137 ± 0.014 band I
0 = 6.47 ± 0.8 for 98Mo (n,γ) 99Mo. These results are discussed and compared with previous measurements and evaluated data in literature. The traditional
method of determining thermal cross-sections and resonance integrals via neutron irradiation with and without Cd shield in
one irradiation position was avoided in this work by neutron irradiation without Cd shield in at least two different neutron
irradiation positions. This method provides alternative way for determining thermal cross-sections and resonance integrals
simultaneously. 相似文献
6.
The cross sections for the 118Sn (n, α)115Cd, 120Sn (n, α)117gCd and 120Sn (n, α)117mCd reactions have been measured in the neutron energy range of 13.5–14.6 MeV using the activation technique and a coaxial
HPGe γ-ray detector. The fast neutrons were produced by the T (d, n) 4He reaction. The neutron energies in the measurements were determined by cross section ratios for 93Nb(n,2n)92mNb and 90Zr(n, 2n)89m+gZr reactions. The results of present work were discussed and compared with theoretical calculation data, measurement results
found in the literature and with the comprehensive evaluation data in ENDF/B-VII.0, CENDL-3.1, JENDL-4.0 libraries. 相似文献
7.
Geraldo Capannesi Alberto Rosada Maurizio Manigrasso Pasquale Avino 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(1):163-168
In geochemistry, the distribution of the Rare Earth Elements (REEs) in earth crust and mantle allows to understand geochemical
cycles and origin and age of igneous rocks. In this article REEs (Ce, Dy, Eu, La, Nd, Sm, Tb, and Yb), Th and U in ores of
the North-Latium (Bracciano area, Ceriti Mt., Fate Mt., Sabatini Mt., Vulsini Mt., Acqua Rossa basin), have been investigated
for evaluating the extraction feasibility for industrial applications. 107 samples were irradiated in the rotating rack of
the TRIGA Mark II reactor of the R.C. Casaccia (ENEA) at neutron flux of 2.6 × 1012
n × cm−2 × s−1 for 12 h together with primary and secondary standards. The gamma spectrometry measurements were performed after 8 h, 3 and
30 days of decay by means of HPGe detector (FWHM 1.75 keV at 1332.5 keV, peak/Compton ratio 55.1, relative efficiency of 22%)
connected to a multi-channel analyzer. The total REE mean content is 105 μg g−1, ranging widely between 2.23 and 410.5 μg g−1 (average coefficient of variation 112%). A similar behavior is found for Th and U: their average levels are 13.5 and 6.0 μg g−1, respectively. A quite good correlation between REEs and Th (and U) is found for Ceriti Mt. (r
2 > 0.8) whereas for the other areas the correlation is <0.7. The results obtained evidence the low U content in the investigated
locations. 相似文献
8.
The determination of gold is based on the photoexcitation reaction 197Au(γ,γ’)197mAu with the half-life of 7.73 seconds and energy of emitted gamma-rays of 279 keV. Three 100 ml aliquots of coarsely ground
Au-ore (grains <2 mm) corresponding to ca. 150–180 g were irradiated for 20 seconds with bremsstrahlung of maximum energy
10 MeV produced by a microtron at the electron beam current of 30–40 μA, 1–10 times reactivation was applied. After 3 seconds
of decay, samples were measured for 20 seconds using scintillation or semiconductor gamma-spectrometry with the detection
limits for an ideal sample down to 0.5 μg·g−1 and 0.1–0.2 μg·g−1 of Au, respectively. Content of U and Th undergoing photo-fission increases the detection limits several times. 相似文献
9.
B. S. Shivashankar H. Naik S. V. Suryanarayana P. M. Prajapati V. K. Mulik K. C. Jagadeesan S. V. Thakare A. Goswami S. Ganesan 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(2):745-750
The reaction cross-sections for 64Ni(n, γ) 65Ni at E
n
= 0.025 eV and 58Ni (n, p) 58Co at E
n
= 3.7 MeV have been experimentally determined using activation and off-line γ-ray spectrometric technique. The thermal neutron
flux used is from the thermal Column of the reactor APSARA at BARC, Mumbai, whereas the neutron energy of 3.7 MeV is from
the 7Li(p, n) reaction at Pelletron facility, TIFR, Mumbai. The 64Ni(n, γ) 65Ni and 58Ni(n, p) 58Co reactions cross-sections from present work are compared with the available literature data and found to be in good agreement.
The 58Ni(n, p) 58Co reaction as a function of neutron energy is also calculated theoretically using TALYS computer code version 1.2 and found
to be higher than the experimental data. 相似文献
10.
M N Matos Reyes M L Cervera M de la Guardia 《Analytical and bioanalytical chemistry》2009,394(6):1557-1562
A sensitive and simple analytical method has been developed for determination of Sb(III), Sb(V), Se(IV), Se(VI), Te(IV), Te(VI),
and Bi(III) in garlic samples by using hydride-generation–atomic-fluorescence spectrometry (HG–AFS). The method is based on
a single extraction of the inorganic species by sonication at room temperature with 1 mol L−1 H2SO4 and washing of the solid phase with 0.1% (w/v) EDTA, followed by measurement of the corresponding hydrides generated under two different experimental conditions directly
and after a pre-reduction step. The limit of detection of the method was 0.7 ng g−1 for Sb(III), 1.0 ng g−1 for Sb(V), 1.3 ng g−1 for Se(IV), 1.0 ng g−1 for Se(VI), 1.1 ng g−1 for Te(IV), 0.5 ng g−1 for Te(VI), and 0.9 ng g−1 for Bi(III), in all cases expressed in terms of sample dry weight. 相似文献
11.
Biological materials containing trace amounts of mercury and selenium were examined using neutron activation analysis. They
were analyzed using Compton suppression and γ–γ coincidence counting. The 279 keV photopeak of activated mercury (203Hg) was analyzed in order to observe the mercury content in these samples. Selenium, an element found in many biological samples,
interferes with the analysis of 203Hg when activated (75Se). Because the selenium interference comes from a cascading emission, Compton suppression was utilized to reduce this interference.
In order to fully characterize the selenium content in the samples, γ–γ coincidence was used which reduced the background
and eliminated bremsstrahlung interference produced from neutron activated phosphorous through the 31P(n, γ)32P reaction which is a pure beta emitter. As a result, we determined the mercury and selenium concentrations in three standard
reference materials, which contain varying ratios of mercury to selenium concentrations. This study also showed that these
types of concentrations can be determined from small (<500 mg) sample masses. Further work needs to be done on wet samples
that require dehydration, as mercury can be lost through this process. 相似文献
12.
S. Ohde K. Tanaka A. Snidvongs H. Matsue 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(2):401-406
A systematic and non-destructive technique is proposed for the determination of boron in coral samples by neutron-induced
prompt γ-ray analysis (PGA) using a thermal neutron guide beam of the JRR-3M reactor. About 50–150 mg samples in sealed FEP
film were irradiated and measured for 5000 s in the PGA system at a neutron flux of 2.4 × 107 n cm−2 s−1. In order to determine B content in coral skeletons, the Doppler-broadened γ-ray peak of 478 keV (10B) was used together with the correction of interference from the Na-peak of 472 keV. The analytical precision was ~3% for
the JCp-1 coral standard. The data (n = 56) obtained by the present method showed a range of B content from 40.7 to 76.9 ppm which is similar to reported values.
Boron in corals showed the highest levels in Rukan-sho (Okinawa) with an average B content of 62.5 ppm, whereas corals collected
from Mizugama (Okinawa), Cebu (the Philippines) and Khang Khao (Thailand) exhibited B contents of 56.5, 53.0 and 45.7 ppm,
respectively. The uptake of boron by living corals may be influenced by seawater pH related to higher seawater B(OH)4−. In this paper we discuss factors controlling the B levels in corals. 相似文献
13.
In recent years, there has been a rapid expansion in the use of radio nuclides for therapeutic purposes. Thulium–167 is an
important radionuclide (T
1/2 = 9.25 d) due to it could be used for tumor and bone studies in nuclear medicine. 167Tm complexed with hydroxy ethylene diamine tetra-acetic acid (HEDTA) could be used with the aim of bone imaging. 167Tm emits a prominent γ ray of 208 keV energy and low energy electrons. This study describes calculations on the excitation
functions of 165Ho(α,2n)167Tm, 167Er(p,n)167Tm, natEr(d,xn)167Tm and natEr(p,xn)167Tm reactions by ALICE/ASH (hybrid and GDH models) and TALYS-1.0 codes. In addition, calculated data by codes were compared
to experimental data that earlier were published and TENDL-2010 database. Moreover, optimal thickness of the targets and physical
yield were obtained by SRIM (stopping and range of ions in matter) code for each reaction. According to the results, the 167Er(p,n)167Tm and 165Ho(α,2n)167Tm reactions are suggested as the best method to produce 167Tm owing to minimum impurities. The TALYS-1.0 code, predict the maximum cross-section of about 382 mb at 11 MeV and 849 mb
at 26 MeV for 167Er(p,n)167Tm and 165Ho(α,2n)167Tm reactions, respectively. Finally, deposition of natEr2O3 on Cu substrate was carried out via the sedimentation method. The 516 mg of erbium(III)oxide with 103.2 mg of ethyl cellulose
and 8 mL of acetone were used to prepare a natEr2O3 layer of 11.69 cm2. 167Tm was produced via the natEr(p,n)167Tm nuclear process at 20 μA current and 15 → 7 MeV protons beam (1 h). Yield of about 3.2 MBq 167Tm per μA h were experimentally obtained. 相似文献
14.
M. A. Shafaei E. Saion K. Wood M. K. Halimah Kh. Rezaee L. A. Mehdipure 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(3):659-662
Potassium is an extremely important major to element to the human body. Potassium in made up of three isotopes with abundances
of 39K at 93.1%, 40K at 0.0118% and 41K at 6.88%. It is also very well known that 40K is to measure the single 1460.8 keV photon from beta-decay. However, this procedure requires a significant amount of sample
and typical counting periods of at least a day in well-shielded germanium counting system. Another approach is to determination
total potassium via neutron activation analysis using the well know 41K (n,γ) 42K(T
1/2 = 12.8 h) reaction and then evaluate 40K using the usual activity equation A = λN. In our laboratory we have effectively used thermal and epithermal neutron flux for neutron activation analysis to determine
potassium in fruits. Upward to 7–9 batches of samples, which each of batch is including 14 samples so can be analysed in 1 day
using only gram quantities of material. In such way on can increase the output of determining 40K by at least on order of magnitude. Result of a detailed investigation optimization of the methodology, quality control and
detection limits will be presented for reference material and various fruits samples. 相似文献
15.
Anna K. Wójcik Paweł Zagrodzki Jerzy W. Mietelski Bogdan Wąs 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(2):415-419
The aim of our studies is to check the possibilities of using proton activation analysis as a competitive method over other
analytical techniques applied for iodine determination. It is well known that long-term irradiation of biological samples
leads to their decomposition and formation of gaseous radiolysis products, which increase the pressure inside the sample container.
In case of using proton beam another problem with liquid samples appears. It is the production of 7Be via spallation reactions 16O(p, spall)7Be. The Compton effect from 7Be γ-line increases the detection limits for isotopes with low-energy γ-lines. AIC-144 cyclotron at The Niewodniczański Institute
of Nuclear Physics Polish Academy of Science can accelerate protons up to energy of 60 MeV which is sufficient for (p,5n)
reaction needed to obtain 123I (T
1/2 = 13.27 h, Eγ = 159 keV, I = 83%) from stable 127I, thus the Compton effect from 7Be was the main factor perturbing the analysis. Separation and removal of 7Be is required to improve the detection limit. The paper presents a method and an example of its application to the determination
of iodine concentration in digested fragments of human thyroids obtained during surgical treatment of patients with different
types of thyroid tumor. 相似文献
16.
B. Wierczinski J. Alstad K. Eberhardt J. V. Kratz R. Malmbeck M. Mendel A. Nähler J. P. Omtvedt G. Skarnemark N. Trautmann N. Wiehl 《Journal of Radioanalytical and Nuclear Chemistry》1998,238(1-2):193-197
The nucleus23Na has been investigated by studying the primary γ-rays emitted from 53 keV neutron capture in it using a high resolution
and high efficiency (100%) HPGe detector and NaI(T1) detector for anti-Compton. 24 primary γ-rays were placed in the24Na, in which 3 primary γ-rays were new ones from a (n, γ) reaction, and reported for the first time. In order to obtain an
exact energy calibration within 7 MeV,56Fe(n,γ)57Fe reaction was used at thermal neutron energy. Intensity calibration was obtained from the27Al(p,γ)28Si reaction atE
p=2046 keV. The neutron binding energy of24Na was determined to be 6959.75 keV. 相似文献
17.
Cyclotron production of <Superscript>211</Superscript>At/<Superscript>211g</Superscript>Po by <Superscript>209</Superscript>Bi(α,2n) reaction 总被引:1,自引:1,他引:0
S. Morzenti M. L. Bonardi F. Groppi C. Zona E. Persico E. Menapace Z. B. Alfassi 《Journal of Radioanalytical and Nuclear Chemistry》2008,276(3):843-847
Astatine-211 (T
1/2 = 7.214 h) is an α-emitter at secular equilibrium by EC with its ultra-short-lived α-emitting daughter, polonium-211g (T
1/2 = 0.516 s), with a high Linear Energy Transfer (LET — 130 eV·nm−1) and a half-life suitable for metabolic radiotherapy; the overall α branching of the 211At/211gPo system is 100%. The direct production of 209Bi(α,2n)211At/211gPo seems the most satisfactory method; Bi targets were irradiated at JRC-Ispra Cyclotron of European Commission, EC, using
α-energy higher than 28.61 MeV in order to produce, via 209Bi(α,3n) reaction, small amounts of the γ-emitter 210At (used as internal spike). 相似文献
18.
N. N. Mirashi P. M. Shah S. K. Aggarwal 《Journal of Radioanalytical and Nuclear Chemistry》2008,275(3):479-482
Determination of americium is one of the requirements of chemical quality assurance of plutonium bearing fuel materials. Alpha-spectrometry
is generally used for the determination of 241Am in Pu bearing fuels since the efficiency of semiconductor detector used for alpha-spectrometry is independent of the alpha-particle
energy in the 4 to 8 MeV range. However, this method has limitations for Pu samples containing extremely small or very large
amounts of 241Am. Thus an alternative methodology based on alpha/gamma (α/γ) activity ratio was developed and tested using different samples.
The method is based on the determination of total γ-activity (of 60 keV peak) of an aliquot of the solution and the total
α-activity present in the aliquot. The method is fast as it does not involve chemical separation of Pu and Am as required
in the alpha-spectrometric method. Data obtained on synthetic and real life samples demonstrates the usefulness of the developed
alpha/gamma ratio method for the determination of 241Am in Pu bearing fuel samples. 相似文献
19.
B. N. Plakhutin 《Journal of Structural Chemistry》1998,39(2):147-157
A method for calculating the energies of electronic states arising from a degenerate open shellγ
N in terms of integral invariants Hk(γ,γ) is presented. The calculation proceeds from expansions for the electron repulsion integrals 〈mm/nn〉 on degenerate orbitals ofγ symmetry in terms of Hk(γ,γ). The energies of states for theγ
N electronic configurations with dimγ≤3 (eN and tN configurations) are tabulated.
Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 2, pp. 183–195, March–April, 1998.
This work was supported by RFFR grants No. 96-03-01167 and 96-03-34035. 相似文献
20.
A. Simonits L. Moens F. De Corte A. De Wispelaere J. Hoste 《Journal of Radioanalytical and Nuclear Chemistry》1981,67(1):61-74
The induced activity of the99Mo isotope is mostly determined via the 140.5 keV γ-line, which is the strongest gamma-ray of its daughter,99mTc. Some recent literature, however, indicates a direct feeding of this energy level from the mother isotope as well. Considering
the importance of this line in practice as well as the large controversy and scattering in relevant nuclear data available
at present, a combined effort was made to remeasure this questionable absolute intensity. A relative method of irradiating
a Mo-target with reactor neutrons and repeatedly measuring its (n,γ) induced activity relative to the 181.1 keV and 739.5
keV gamma lines of99Mo as internal references was used. The weighted average of different runs yielded γ(99Mo, 140.5 keV)=(5.07±0.37)%. As a consequence, when the 140.5 keV gamma line is used, the contribution from the99Mo mother isotope should always be taken into account, e.g. in neutron cross-section measurements and neutron activation analysis. 相似文献