Search results for "neutron activation"
showing 10 items of 41 documents
The Moss Biomonitoring Method and Neutron Activation Analysis in Assessing Pollution by Trace Elements in Selected Polish National Parks
2020
The concentrations of trace elements in feather moss Pleurozium schreberi (Brid.) Mitt. were used to indicate the relative levels of air pollution by trace elements in Polish national parks. Pleurozium schreberi was collected from nine national parks. The highest concentrations were recorded in the moss samples from the southern and most industrialised part of the country; the lowest from northern and north-eastern Poland. A comparison of data obtained from Polish national parks in the 1970s and 1990s showed a significant decrease in the concentrations of heavy metals. In the linear covariability estimation, the t quantile approach was used for multi-element comparison. A number of positive…
Standardisation of elemental analytical techniques applied to provenance studies of archaeological ceramics: an inter laboratory calibration studyEle…
2002
Chemical analysis is a well-established procedure for the provenancing of archaeological ceramics. Various analytical techniques are routinely used and large amounts of data have been accumulated so far in data banks. However, in order to exchange results obtained by different laboratories, the respective analytical procedures need to be tested in terms of their inter-comparability. In this study, the schemes of analysis used in four laboratories that are involved in archaeological pottery studies on a routine basis were compared. The techniques investigated were neutron activation analysis (NAA), X-ray fluorescence analysis (XRF), inductively coupled plasma optical emission spectrometry (I…
Reverse paintings on glass--a new approach for dating and localization.
2009
Samples from 20 reverse paintings on glass from different regions have been analyzed by NAA with the aim to deduce the place and date of their origin. A separation of earlier and later paintings was due to different concentrations of K and Na, because a sodium-containing flux came into use after 1870. Since in southern Germany quartz sand, and in the eastern area quartz rock had been used for glass manufacture, specific impurities could be used to distinguish southern from eastern glasses.
Determination of gold in two Egyptian gold ores using instrumental neutron activation analysis
2003
Abstract The applicability of thermal neutron activation analysis for the determination of gold and other elements in two Egyptian gold ores has been studied. Ten samples collected from El Sukari and Atud in the Eastern Desert-Egypt have been analyzed. The samples were properly prepared together with their standards and simultaneously irradiated in a neutron flux of the order 7×10 11 n/cm 2 s using the TRIGA research reactor at Mainz. Short-term (1 and 5 m) irradiation in the pneumatic system was also used for detection of the elements with shorter half-lives. After activation, the samples were subjected to γ -ray spectrometry using a high-purity germanium detection system and computerize…
Determination of macro, micro nutrient and trace element concentrations in Indian medicinal and vegetable leaves using instrumental neutron activatio…
1999
Abstract Leafy samples often used as medicine in the Indian Ayurvedic system and vegetables were analyzed for 20 elements (As, Ba, Br, Ca, Ce, Cr, Cs, Co, Eu, Fe, K, La, Na, Rb, Sb, Sc, Sm, Sr, Th, Zn) by employing Instrumental Neutron Activation Analysis (INAA). The samples were irradiated at the 100 kW TRIGA-MAINZ nuclear reactor and the induced activities were counted by gamma ray spectrometry using an efficiency calibrated high resolution High Purity Germanium (HPGe) detector. The concentration of the elements in the medicinal and vegetable leaves and their biological effects on human beings are discussed.
Fast determination of impurities in metallurgical grade silicon for photovoltaics by instrumental neutron activation analysis
2010
Standard wafer solar cells are made of near-semiconductor quality silicon. This high quality material makes up a significant part of the total costs of a solar module. Therefore, new concepts with less expensive so called solar grade silicon directly based on physiochemically upgraded metallurgical grade silicon are investigated. Metallurgical grade silicon contains large amounts of impurities, mainly transition metals like Fe, Cr, Mn, and Co, which degrade the minority carrier lifetime and thus the solar cell efficiency. A major reduction of the transition metal content occurs during the unidirectional crystallization due to the low segregation coefficient between the solid and liquid phas…
Trace element determination in sediments: a comparative study between neutron activation analysis (NAA) and inductively coupled plasma-mass spectrome…
2000
An inductively coupled plasma-mass spectrometry (ICP-MS) method has been employed for trace element determination in five real sediment samples and a standard reference material. These samples were mineralized by dry ashing at 550°C and fused at 1100°C for 30 min with lithium metaborate. Dissolved samples were measured by a semiquantitative methodology with external calibration and with Rh as an internal standard. More than 50 elements have been measured. As a reference technique, a direct analysis of the solid samples was carried out by neutron activation analysis. Results obtained by ICP-MS have been compared with those obtained by neutron activation analysis (NAA) by applying the paired …
Electrothermal Atomic Absorption Determination of Chromium in Sediments
1999
Abstract An electrothermal atomic absorption spectrometric method has been developed to determine total chromium concentration in natural sediment samples. Samples were mineralized by dry ashing at 550°C and fused at 1100°C for 30 min with lithium metaborate. Dissolved samples were injected in graphite tubes, mineralized at 1100°C, and atomized at 2600°C. Standard addition calibration made unnecessary the use of chemical modifiers. The method provided a limit of detection from 23 to 45 ng liter −1 . The relative standard deviation for chromium determination was between 3 and 14%. Results obtained for a standard reference material agree well with the certified value. A series of natural samp…
Validation of a method for neutron dosimetry and spectrometry using neutron activation of metal discs
2009
A technique for neutron dosimetry and spectrometry based on neutron activation of different metal discs has been studied. After exposure to a neutron field, the radionuclides produced in the discs are detected using low-level gamma-ray spectrometry and the neutron spectrum is obtained using a spectrum unfolding technique. In order to validate the method, irradiation was performed in a well-characterised (252)Cf neutron reference field. Furthermore, the detector was used to determine the neutron fluence rate and spectrum at a storage place for MOX nuclear fuel. The results of the two measurements are reported and discussed.
Neutron flux and gamma dose measurement in the BNCT irradiation facility at the TRIGA reactor of the University of Pavia
2018
Abstract University of Pavia is equipped with a TRIGA Mark II research nuclear reactor, operating at a maximum steady state power of 250 kW. It has been used for many years to support Boron Neutron Capture Therapy (BNCT) research. An irradiation facility was constructed inside the thermal column of the reactor to produce a sufficient thermal neutron flux with low epithermal and fast neutron components, and low gamma dose. In this irradiation position, the liver of two patients affected by hepatic metastases from colon carcinoma were irradiated after borated drug administration. The facility is currently used for cell cultures and small animal irradiation. Measurements campaigns have been ca…