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"Landsberger, Sheldon"
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Neutron activation analysis using gamma-gamma coincidence to eliminate spectral interferences
The use of neutron activation analysis (NAA) sometimes has limitations with the identification of specific gamma ray peaks due to spectral interferences. The implementation of gamma-gamma coincidence techniques using the XIA Pixie-16 system has demonstrated the ability reduce many of these challenges. Experiments were performed on two different NIST reference materials using gamma-gamma coincidence techniques to identify long-lived radionuclides that are often difficult to evaluate due to various spectral interferences. The experiments have shown that utilizing gamma-gamma coincidence with the XIA Pixie-16 system for
177m
Lu,
124
Sb,
160
Tb,
175
Yb, and
153
Sm can eliminate spectral interferences and high backgrounds due to Compton scattering.
Journal Article
Disposable Paper Cups: A Study on Potentially Toxic Elements, Radiological Impact, and Feasibility of Valuable Elements Recovery
This study characterizes single-use paper cups with respect to potentially toxic elements, radiological impact, and the potential of economic metals recovery from incineration residue. Thirty-six elements were identified in the analysis of paper cups, including naturally occurring radionuclides 40K, Th, and U, as well as potentially toxic elements such as Al, Ba, Co, Cr, Cu, Mn, Mo, and V using neutron activation analysis. The determined mass fractions varied significantly, with Mg, Al, and Ca present in notably high concentrations. A comparison with plastic cups revealed higher mass fractions of most elements in paper cups. The study also evaluated the potential for valuable element recovery from the incineration ash of paper cups. It demonstrated a promising potential for recovery of Cu—especially from blue and green cups—and Mg, as their mass fractions are above the ore cut-off grade. The amount of CO2 emissions from the incineration of paper cups was estimated at 1.77 kg/kg. The activity concentrations of 40K, Th, and U were estimated in the incineration ash, with 40K accounting for around half of the total detected activity. The median radioactivity was 35 Bq/kg. Although the radioactivity levels are low, they should be considered due to the large volume of paper cup waste. The radiological risk was assessed using various hazard indices, indicating minimal risk to human health. The dose rate and the annual dose are well below the recommended limits, and the excess lifetime cancer risk (ELCR) of 2.17 × 10−5 is well below the typical safety limit.
Journal Article
Leaching of Potentially Toxic Elements from Paper and Plastic Cups in Hot Water and Their Health Risk Assessment
This study aims to investigate the release of potentially toxic elements from disposable paper and plastic cups when exposed to hot water, simulating the scenario of their use in hot beverage consumption, and to assess the associated health risks. By using ICP-MS, twelve potentially toxic elements, namely As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Pb, Sb, V, and Zn, were determined in leachates, revealing significant variability in mass fractions between paper and plastic cups, with plastic cups demonstrating greater leaching potential. Health risk assessments, including hazard quotient (HQ) and excess lifetime cancer risk (ELCR), indicated minimal non-carcinogenic and carcinogenic risks for most elements, except Pb, which posed elevated non-carcinogenic risk, especially in plastic cups. Children showed higher relative exposure levels compared to adults due to their lower body weights (the HQ in children is two times greater than in adults). Overall, the findings of the current study underscore the need for stricter monitoring and regulation of materials used in disposable cups, especially plastic ones, to mitigate potential health risks. Future investigations should assess the leaching behavior of potentially toxic elements under conditions that accurately mimic real-world usage. Such investigations ought to incorporate a systematic evaluation of diverse temperature regimes, varying exposure durations, and different beverage types.
Journal Article
An online neutron activation analysis database (NAADB)
An online computer program for an interactive database was specifically developed for neutron activation analysis (NAA). The software written in Java includes gamma-ray catalog, neutron activation calculator for activity calculations and decay schemes. For the novice, expert and educator this program can greatly reduce needed information in NAA.
Journal Article
An E-learning tool as living book for knowledge preservation in neutron activation analysis
The International Atomic Energy Agency (IAEA) has implemented a detailed E-learning on-line course in neutron activation analysis (NAA). Existing books and guidance documents on the concepts and execution of NAA are out of date and not sufficient anymore to ensure the transfer of current knowledge on its practice. The overall objective of the E-learning tool in NAA is to realize a ‘living book’, summarizing the basic concepts and providing practical information on the implementation of the methodologies which can be more easily updated than a common book, allowing also for visualization using contemporary media.
Journal Article
Measurement of Photoneutron Yields Using the RPI LINAC and Assessment of Evaluated Photoneutron Data for Tantalum and Beryllium
A new experiment configuration was designed, developed, and implemented to measure photoneutron yields using the Rensselaer Polytechnic Institute (RPI) electron linear accelerator (LINAC) at the RPI Gaerttner LINAC Center. The experiment configuration includes a new target assembly that converts the LINAC electron beam into a high energy bremsstrahlung photon flux incident upon a sample material of interest. The photons excite nuclei in the sample of interest, which can subsequently emit neutrons (photoneutrons). The photoneutrons emitted in the direction of the detector system travel through a series of collimated vacuum pipes before reaching a pair of proton-recoil high-energy neutron detectors. The signals generated by the neutron detectors are processed using a digital data acquisition system and subsequently analyzed to determine the energy-dependent photoneutron yield from the sample of interest. The new experiment configuration was used to perform proof-of-concept experiments to measure the photoneutron yields from samples of tantalum and beryllium. The measured results were then compared against the results from Monte Carlo simulations of the detailed experiment configurations to perform preliminary assessments of evaluated photoneutron data libraries.
Journal Article
Interferences in the determination of lutetium using neutron activation analysis
We have investigated the severity of interferences in the determination of lutetium in neutron activation analysis. The preferred reaction makes use of the large radiative capture cross section of 2090 b for 176Lu(n,γ)177Lu, which emits a 208.4 keV gamma emission (t1/2 = 6.73 days). Activation of 176Lu simultaneously produces 177mLu, which also emits at 208.4 keV (t1/2 = 160.4 days). We found that these convolutions did not produce significant error in lutetium analysis for a sample of NIST 1633c, even for longer decay times used to reduce the 239Np interference at 209.8 keV.
Journal Article
Investigation of bauxite residue (red mud) in terms of its environmental risk
This research describes the method of neutron activation analysis (NAA) and Compton suppression for determination of some toxic elements in red mud (collected from Eti Seydisehir Aluminium Plant in Turkey). Furthermore, short-term leaching tests of elements were undertaken on red mud to evaluate in terms of the environmental impact. Morphological characterizations and qualitative element composition of red mud were also performed by SEM–EDX analysis. Fe, Al, Na, Ti and Ca contents in red mud were found significantly high. It can be concluded that some toxic elements may not easily mobile under the environmental conditions.
Journal Article
Environmental assessment of red mud by determining natural radionuclides using neutron activation analysis
Bauxite residues (red mud) produced by digestion of bauxite ore during the production of alumina contain naturally occurring radionuclides such as 238U, 232Th and 40K and toxic elements such as Al, Cr, Co, Mn and Ni. In this research, red mud collected from Eti Seydisehir Aluminium Plant in Turkey was studied to determine the concentration of natural radionuclides for evaluating their radiological effects. Short-term leaching tests of radionuclides were performed by Toxicity Characteristic Leaching Procedure (TCLP)-1311 method to assess in terms of their environmental impact. Furthermore, self-attenuation factors were experimentally determined using radioactive point sources with two different amounts to ascertain how gamma rays are attenuated in the residue depending on the energy and the volume of residue. The activity concentrations of 234,235,238U, 232Th and 40K in red mud and leachate samples were determined by neuron activation analysis and Compton suppression methods. The method was tested using NIST (National Institute of Standards and Technology) 1632d and 2709a reference materials. It can be concluded from the results of leaching tests that natural radionuclides may not easily be mobile under environmental conditions and the mobility of the radionuclides depends on the pH value of water and contact time with the water. The activity concentration index which is the most commonly used calculation method was applied to the samples and the results showed that the reuse of red mud as a secondary raw material may not be hazardous depending on the percentage of utilization of it.
Journal Article