共查询到20条相似文献,搜索用时 46 毫秒
1.
M. Segawa H. Matsue Y. Sekiya S. Yamada T. Shinohara T. Oku H. Sasao J. Suzuki H. M. Shimizu 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(3):647-651
We have constructed a new system which could analyze a position distribution of several elements in a sample with 2 dimensional
prompt γ-ray analysis (2D PGA) system using focused neutron beam at JAEA. We aimed that the system could analyze local information
in a sample with a good signal γ-ray from interested elements to noise of background γ-ray ratio. As a result, this system
could determine the position resolution and spatial resolution within 1 mm. 相似文献
2.
A comprehensive compilation of X- and γ-ray emitting isotopes produced by the (n, γ) reaction is reported in this paper for
application to instrumental neutron activation analysis (INAA). The X- and γ-ray sensitivities are computed theoretically
by a computer code. Interfering photons from isotopes of neighbouring elements are identified by the code and the percentage
interference is computed. Additionally an advantage factor (X-ray: γ-ray sensitivity) is computed, which is a figure of merit
for X-ray spectroscopy in INAA. Further, mathematical representation of background continua for typical matrices encountered
in INAA allow the calculation of elemental detection limits for the X-ray and γ-ray photons. 相似文献
3.
J. Kuncíř J. Benada Z. Řanda M. Vobecký 《Journal of Radioanalytical and Nuclear Chemistry》1970,5(2):369-378
The use of high-resolution Ge(Li) detectors in non-destructive instrumental neutron activation analysis (INAA) of mineral
materials makes possible the simultaneous determination of a number of trace elements. In routine applications of INAA the
use of a multi-element standard (MES) has proved to have advantages over a set of standards for each determined element. An
MES has been prepared containing 8 trace elements mixed in a suitable proportion and giving, after neutron activation, long-lived
γ-emitters, the γ-ray lines of which regularly occur in the γ-ray spectra of silicate mineral materials. This method has been
used in the determination of Sc, Cr, Co, Rb. Cs, Eu, Hf and Th in samples of standard rocks and moldavites. 相似文献
4.
Monte Carlo calculations were carried out to study the dependence of γ-ray yield on the bulk density and moisture content
of a sample in a thermal-neutron capture-based prompt gamma neutron activation analysis (PGNAA) setup. The results of the
study showed a strong dependence of the γ-ray yield upon the sample bulk density. An order of magnitude increase in yield
of 1.94 and 6.42 MeV prompt γ-rays from calcium in a Portland cement sample was observed for a corresponding order of magnitude
increase in the sample bulk density. On the contrary the γ-ray yield has a weak dependence on sample moisture content and
an increase of only 20% in yield of 1.94 and 6.42 MeV prompt γ-rays from calcium in the Portland cement sample was observed
for an order of magnitude increase in the moisture content of the Portland cement sample. A similar effect of moisture content
has been observed on the yield of 1.167 MeV prompt γ-rays from chlorine contaminants in Portland cement samples. For an order
of magnitude increase in the moisture content of the sample, a 7 to 12% increase in the yield of the 1.167 MeV chlorine γ-ray
was observed for the Portland cement samples containing 1 to 5 wt.% chlorine contaminants. This study has shown that effects
of sample moisture content on prompt γ-ray yield from constituents of a Portland cement sample are insignificant in a thermal-neutrons
capture-based PGNAA setup. 相似文献
5.
Y. J. Park B. C. Song M. I. Chowdhury K. Y. Jee 《Journal of Radioanalytical and Nuclear Chemistry》2004,260(3):585-594
A neutron induced prompt γ -ray spectrometry (NIPS) facility has been developed at the Nuclear Chemistry Research Division,
of the Korea Atomic Energy Research Institute (KAERI) with the aim of analyzing the major components of various elements in
aqueous samples. The facility is equipped with a 252Cf neutron source and a γ-γ coincidence setup with two n-type coaxial HPGe detectors based on NIM spectrometric modules in
association with data acquisition and spectral analysis systems. The development of the system, its set-up and the calibration
of detection efficiency up to 8 MeV using a set of radionuclides and the (n,γ) reactions of chlorine are described in the
paper.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
R. Acharya 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(2):291-294
Prompt gamma ray neutron activation analysis methodologies were standardized using a reflected neutron beam and Compton suppressed
γ-ray spectrometer to quantify boron from trace to major concentrations. Neutron self-shielding correction factors for higher
boron contents (0.2–10 mg) in samples were obtained from the sensitivity of chlorine by irradiating KCl with and without boron.
This method was validated by determining boron concentrations in six boron compounds and applied to three borosilicate glass
samples with boron contents in the range of 1–10 mg. Low concentrations of boron (10–58 mg kg−1) were also determined in two samples and five reference materials from NIST and IAEA. 相似文献
7.
A computer program is described to perform the identification of isotopes in neutron activated samples. The γ-ray energies
as obtained from a Ge(Li) γ-ray spectrum are compared with those of a library, containing data for about 250 isotopes. Isotopes
whose γ-ray energies match closely with the unknowns are selected as possible constituents. Unlikely attributions are then
eliminated by a careful inspection of the γ-rays found. Further exploitation of half-life, the way of production and the sensitivity
for the given irradiation and measurement conditions, allow the selection of the most likely constituents in the source. The
results of the automated identification agree closely to those obtained by an experienced investigator. The program is written
in FORTRAN IV for a PDP-9 computer with a 16 K word memory. 相似文献
8.
Pulsed neutron-based on-line coal analysis 总被引:2,自引:0,他引:2
L. Dep M. Belbot G. Vourvopoulos S. Sudar 《Journal of Radioanalytical and Nuclear Chemistry》1998,234(1-2):107-112
A neutron generator-based on-line coal analysis system is described, capable of measuring the content of the major and minor
elements in coal. The system utilizes reactions produced from fast and themal neutrons, as well as from neutron activation
with half lives of seconds or minutes. Characteristic γ-rays, detected with BGO detectors are used for the identification
of the various chemical elements. The method for the analysis of the γ-ray spectra is presented, and the measurements of coal
density, carbon and sulfur content are shown. 相似文献
9.
Y. Murata S. Hirai M. Okamoto H. Kakihana 《Journal of Radioanalytical and Nuclear Chemistry》1977,36(2):525-535
A new system of γ-ray spectrometry has been designed and constructed. This system performs a precise, quick and automatic
activation analysis using our nuclear reactor (TRIGA-II Research Reactor) as a neutron source. The main components are detector
system consisted of a high resolution Ge(Li) detector settled in a shielding cabinet and a well-type NaI(Tl) scintillation
counter for anti-Compton measurement, and data acquisition and spectra analysis system performed independently by two mini
computer. The system has operated for atmospheric aerosols as an example of activation analysis. 相似文献
10.
L. N. Chau N. T. Hiep V. T. Ha N. C. Hai 《Journal of Radioanalytical and Nuclear Chemistry》1992,165(6):351-362
A facility for neutron capture prompt -ray spectroscopy for activation analysis has been intstalled at the tangential beam tube of the 500 kW Dalat reactor. Using a single crystal of silicon for filtering the thermal neutron beam and the 73 cm3 HP-G detector shielded by common materials with flexible configurations suitable to various samples, LOD of nearly 30 elements were estimated. Applications of PGAA in the determination of elemental concentrations in biological, environmental, geological and industrial product samples are presented. 相似文献
11.
M. L. Verheijke 《Journal of Radioanalytical and Nuclear Chemistry》1972,10(2):299-314
A program is presented for the analysis of γ-ray spectra from Ge(Li) multichannel spectrometer systems. The program is written
in ALGOL-60 for off-line working with a large Philips Electrologica X8 computer. It has been extensively used in thermal neutron
activation analysis practice. 相似文献
12.
Exploration and modification of data for k
0-PGAA (prompt γ-ray activation analysis) values used as standards for k
0 standardization are needed. An integrated system has been installed and calibrated in Hot Laboratories Center for PGAA, using
252Cf isotopic neutron source with neutron flux of 6.16E8 n/cm2 s. The prompt k
0-factors of about 12 elements were determined versus the 1951.1 keV γ-ray of the 35Cl, as well as analyzing crude oil and oil product samples. The concentrations of the elements in crude oil H, B, Mg, Al,
Na, Si, P, S, Cl, V and Cd were 1.18E5, 0.084, 5.48E2, 8.45E2 4.88E2, 1.62E2, 3.72E2, 8.2, 144.3, 393 and 209.2 ppm while
in oil product samples were 1.32E5, 5.87, 4.56E2, 4.22E2, 7.16E3, 699, 157, 8.74, 492.3, 61 and 198.2 ppm. Validation of the
k
0-PGAA was applied in analyzing standard IAEA reference material (soil-7) which give good agreement with the literature data.
The 252Cf neutron beam in radiation position was characterized by the cadmium-ratio method, and found that the cadmium ratio (f), was 160. 相似文献
13.
A method is presented for the determination of bromine in biological fluids that demonstrates the possibility of adapting
neutron activation analysis to large-scale, routine programs. By means of a simple and inexpensive semi-automated system radioactive
bromine is separated from one hundred samples per day. A new procedure for determining bromine through measurement of the
36-keV γ-ray of80m
Br has been developed and incorporated into this method. The advantages achieved with this multipurpose separation system
and low-energy γ-spectrometry are demonstrated through analyses of urine, serum, plasma and saliva. 相似文献
14.
S. S. Nargolwalla J. Niewodniczanski J. E. Suddueth 《Journal of Radioanalytical and Nuclear Chemistry》1970,5(2):403-423
The experimental sensitivity for 72 different elements using 3 MeV neutron activation has been investigated. Using a 200 kV
Cockcroft-Walton neutron generator with a 3 MeV neutron flux of about 1.5·106n·cm−2·sec−1, γ-ray spectra of 51 elements were obtained with a sufficient number of photopeak counts for sensitivity calculations using
a photopeak integration method. A useful table summarizing the sensitivity results is given. That 3 MeV neutron activation
analysis is practical, is demonstrated by the experimental sensitivities obtained.
Guest worker from the Institute of Nuclear Techniques, Academy of Mining and Metallurgy, Krakow, Poland, at the National Bureau
of Standards, 1968–1969. 相似文献
15.
J. R. W. Woittiez J. Zonderhuis A. Faanhof H. A. Das 《Journal of Radioanalytical and Nuclear Chemistry》1979,53(1-2):191-201
A simple procedure for the correction of residual dead-time losses in γ-ray spectrometry of mixtures of short-lived radionuclides
is given. It is based on the value of the total deadtime at the beginning of the measurement and three constants which are
characteristics for a given matrix. The application to the instrumental neutron activation analysis of fluorine and sodium
in bone is given as an exaple. 相似文献
16.
T. Bennett D. Cavers J. M. D'Auria 《Journal of Radioanalytical and Nuclear Chemistry》1973,13(1):201-212
The purpose of this study was to demonstrate the versatility of combining the use of high resolution, Ge(Li) γ-detectors with
the techniques of fast neutron activation analysis. A compilation of γ-ray spectra are presented for irradiation of 30 elements
with 14.8 MeV neutrons under standard conditions and the origin of all major photopeaks is determined. 相似文献
17.
R. A. M. Rizk A. H. El-kateb A. M. Abdul-kader 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(1):139-145
Developments and applications of on-line nuclear gauges in the coal industry are highly requested. In this work, a nuclear
ash gauge for coal, based on γ-ray transmission techniques is developed. Single and dual energy γ-ray beams are used to determine
the ash content of coal. The percentage ash content as a function of the γ-ray intensities transmitted through coal samples
is measured and sensitivity curves are obtained. An empirical formulation relating the ash content values to the γ-ray intensities
is derived. Preliminary results show that both single and dual energy γ-ray transmission techniques can be used to give a
rapid on-line estimation of the ash concentration values in coal with low cost and reasonable accuracy, but the dual one is
much preferable. 相似文献
18.
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
19.
T. Belgya 《Journal of Radioanalytical and Nuclear Chemistry》2008,276(3):609-614
The 14N(n,γ)15N reaction is a primary γ-ray source for high energy calibration of detectors. The relative γ-ray-intensities of 15N and the relative γ-ray detection efficiency function have been simultaneously determined up to 10 MeV from γ-peak areas
alone. Absolute γ-ray-intensities were obtained with proper renormalization to known absolute intensity. The influence of
these new intensity values are assessed for use in PGAA. Any consistently used set of calibration intensities applied in the
creation of library values and for analysis do not influence the concentrations. Contrary to this, quantities based on sums
of γ-ray cross sections may provide different answers with the new 15N intensities and they give means to validate them. 相似文献
20.
A sensitive procedure for the simultaneous determination of trace levels of osmium and ruthenium in platinum, by thermal neutron
activation analysis utilizing γ-ray spectrometry, was developed. The radiochemical separation method utilized perchloric acid
for a selective oxidation of osmium and ruthenium to the volatile tetroxides. The distillation of the tetroxides greatly reduced
the radiation hazard presented by the bulk of the activities in the matrix. Activities of 15-day191Os and 40-day104Ru were measured by accumulation of pulses from a 3″ diameter NaI(Tl) crystal detector. Analyses of γ-ray spectra were achieved
using digital computer techniques. The procedure provided analyses for a high purity platinum stock of 0.032±0.007 ppm Os
and 0.044±0.005 ppm Ru.
Work was performed at the Ames Laboratory of the U. S. Atomic Energy Commission, Contribution No. 3073. 相似文献