Search results for "neutron activation"
showing 10 items of 41 documents
Determination of impurity distributions in ingots of solar grade silicon by neutron activation analysis
2017
AbstractIn a series of crystallization experiments, the directional solidification of silicon was investigated as a low cost path for the production of silicon wafers for solar cells. Instrumental neutron activation analysis was employed to measure the influence of different crystallization parameters on the distribution of 3d-metal impurities of the produced ingots. A theoretical model describing the involved diffusion and segregation processes during the solidification and cooling of the ingots could be verified by the experimental results. By successive etching of the samples after the irradiation, it could be shown that a layer of at least 60 μm of the samples has to be removed to get r…
Determination of phosphorus by instrumental neutron activation and bremsstrahlung measurement in bone samples
1997
A non destructive method based on the31P(n,γ)32P reaction for the assay of phosphorus in bone samples is described. This method involves a thermal neutron irradiation of 2 minutes in a reactor followed by the measurement of the bremsstrahlung produced by the β− of32P in a Ge-detector surrounded by an anti-Compton shield. Accuracy and precision were tested by analysing the certified NIST 1486 Bone Meal reference material and tri-calcium phosphate (Ca3(PO4)2) samples. The value obtained for the reference material was in good agreement with the certified value and with relative standard deviation of 4.1% the precision was acceptable. The value obtained for Ca3(PO4)2 shows a deviation of −6% fr…
Trace elemental composition of curry by inductively coupled plasma optical emission spectrometry (ICP-OES)
2008
A methodology based on inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave-assisted acid digestion was developed to determine the content of traces elements in curry samples from the Spanish market. The methodology was validated in terms of accuracy by the analysis of citrus and tomato leaf reference materials achieving comparable results with the certified values. The trace metal content of curry samples was compared with data available from previously published reports concerning Indian samples, especially in terms of heavy metal composition, in order to guarantee the quality of the commercially available spices in the European countries. Values found for th…
Determination of organic fluorine in aqueous samples with neutron activation analysis in comparison with the DIN method
1996
Neutron activation analysis (NAA) has been used as detection technique for adsorbable organic fluorine in aqueous samples. The results have been compared with the standardized DIN method which uses a fluoride-ion-selective electrode (ISE).
Beta Decay Studies of Neutron Rich Nuclei Using Total Absorption Gamma-ray Spectroscopy and Delayed Neutron Measurements
2010
International audience; A complete characterisation of the β-decay of neutron-rich nuclei can be obtained from the measurement of β-delayed gamma rays and, whenever the process is energetically possible, β-delayed neutrons. The accurate determination of the β-intensity distribution and the β-delayed neutron emission probability is of great relevance in the fields of reactor technology and nuclear astrophysics. A programme for combined measurements using the total absorption gamma-ray spectroscopy technique and both neutron counters and neutron time-of-flight spectrometers is presented.
Determination of elemental levels in medicinally important Indian leaves by instrumental neutron activation analysis
1998
Levels of As, Ba, Br, Ca, Ce, Cl, Cr, Cs, Eu, Fe, Hg, I, K, La, Mg, Mn, Na, Ni, Rb, Sb, Sc, Sm, Sr, Th, Zn, and U have been determined in ten leaves widely used in ayurvedic medicine by instrumental neutron activation analysis (INAA). The neutron irradiations were performed with a 100 kW Triga nuclear reactor and the induced activity was counted with a gamma-ray spectrometer. Based on elemental levels obtained the utility of these leaves in medicine are discussed.
Neutron fluence spectrometry using disk activation
2009
Abstract A simple and robust detector for spectrometry of environmental neutrons has been developed. The technique is based on neutron activation of a series of different metal disks followed by low-level gamma-ray spectrometry of the activated disks and subsequent neutron spectrum unfolding. The technique is similar to foil activation but here the applied neutron fluence rates are much lower than usually in the case of foil activation. The detector has been tested in quasi mono-energetic neutron fields with fluence rates in the order of 1000–10000 cm −2 s −1 , where the obtained spectra showed good agreement with spectra measured using a Bonner sphere spectrometer. The detector has also b…
Forensic investigation of brick stones using instrumental neutron activation analysis (INAA), laser ablation-inductively coupled plasma-mass spectrom…
2009
Abstract Brick stones collected from different production facilities were studied for their elemental compositions under forensic aspects using laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS), instrumental neutron activation analysis (INAA) and X-ray fluorescence analysis (XRF). The aim of these examinations was to assess the potential of these methods in forensic comparison analyses of brick stones. The accuracy of the analysis methods was evaluated using NIST standard reference materials (679, 98b and 97b). In order to compare the stones to each other, multivariate data analysis was used. The evaluation of the INAA results (based on the concentrations of V, Na, K, …
Determination of Platinum-Group Elements (PGE) from catalytic converters in soil by means of docimasy and INAA.
1996
The nickelsulfide fire assay (docimasy) for the enrichment of platinum-group elements (PGEs) has been modified for the use with small samples and combined with instrumental neutron-activation analysis (INAA). This procedure has been applied to the determination of PGEs exhausted from catalytic converters and deposited in soil near the Wiesbadener Kreuz (highway A3, Frankfurt-Koln). Our results show a considerable enhancement of the Pt (up to 330 ng/g), Pd (6.6 ng/g) and Rh (7.5 ng/g) contents close to the highway.
Test of multielement analysis of bone samples using instrumental neutron activation analysis (INAA) and anti-Compton spectrometry
1997
INAA and anti-Compton spectrometry has been employed in the analysis of test bone samples. Validity and accuracy of the method were checked by the use of two biological reference materials procured from the National Institute of Standards and Technology, USA (NIST) and the International Atomic Energy Agency, Austria (IAEA). NIST 1486 Bone Meal (ca. 200–800 mg) and A-11 Milk Powder (ca. 200–600 mg) samples were irradiated in the 100 kW TRIGA Mainz reactor. Concentrations of 13 elements in both biological reference materials have been determined and were found in good agreement with the certified and provisional values.