Noble metals have been analyzed in high purity copper and a platinum ore to be certified as reference materials. Analyses
were performed by photon activation analyses using both conventional gamma and low energy photon spectroscopy. Our values
agree very well with those of other laboratories using various analysis methods. Low energy photon spectroscopy is more advantageous
than gamma spectroscopy from various points of view.
Sensitivity data for low energy photon spectroscopy used in photon activation analysis are compiled and compared with those
for classical gamma-spectroscopy. All elements of the periodic table with a few exceptions were irradiated with 30 MeV-bremsstrahlung
of a linear electron accelerator. Low energy photon spectra were taken with a LEP-detector as well as with a coaxial Ge(Li)-detector.
Resulting data were processed by computer. The results show that in some cases low energy photon spectroscopy used in photon
activation analysis provides higher sensitivity than can be achieved by classical gamma-spectroscopy.
A survey is given on the use of X-ray spectroscopy for the qualitative and quantitative analysis of samples activated by 30
MeV bremsstrahlung from an electron linear accelerator. Detection limits are calculated from the measured X-ray spectra and
compared with those for γ-ray spectroscopy. The advantages and limitations of the method are discussed. Some practical applications
of X-ray spectroscopy in nondestructive multielement analysis are quoted.
The contamination of potable water aquifers by heavy metals is one of the most severe environmental threats. For the transport of heavy metals from various types of contaminated sites into the ground water and also into surface water aquifers, humic substances (HS) are recognized to be of main importance. Dissolved in natural waters humic substances are readily complexed with a variety of metal ions. Therefore, humic substances are of cardinal importance for the migration and, consequently, the pollution of ground waters with heavy metals. Our paper presents the results of a comprehensive comparison of several isolated humic acids of soils of different origin (different geochemical milieu) and their metal complexes. Two polluted sites in Germany, which differ in their geochemical milieu (pH-value) were selected. The aim of our experiments was to describe the properties of terrestrial humic substances depending on their origin and genesis as well as the effects of the transport of humic substance-bound metals into the water-unsaturated soil zone. After determination of heavy metals in the soils by photon activation analysis the activated soil was used as an inherent tracer in batch experiments with the isolated humic acid. After adsorption of the loaded humic acid on an XAD-8 resin column, the partition of metals mobilized by humic acids could be quantified. There are correlations of the formation of metal-humic complexes with the soil pedogenes, with the pH-value as well as with the humic acid concentration.
Large-volume instrumental photon activation analysis (IPAA) was used for the investigation of shredded electronic waste material.
Sample masses from 1 to 150 grams were analyzed to obtain an estimate of the minimum sample size to be taken to achieve a
representativeness of the results which is satisfactory for a defined investigation task. Furthermore, the influence of irradiation
and measurement parameters upon the quality of the analytical results were studied. Finally, the analytical data obtained
from IPAA and instrumental neutron activation analysis (INAA), both carried out in a large-volume mode, were compared. Only
parts of the values were found in satisfactory agreement.
Authors:C. Segebade, G. Lutz, H. Weise, and H. Fusban
Interferences of different types (competing reactions, overlapping photons emission energies etc.) occur more frequently during
activation analysis with high energy exciting radiation that in conventional thermal neutron activation. Three main types
of interference in high energy photon activation analysis (PAA) have been determined quantitatively, using experimentally
obtained data exclusively. Based on the results presented, it is possible in many critical cases to improve significantly
the accuracy of analysis results obtained by PAA.
Authors:Z. Sun, C. Segebade, D. Wells, and J. Green
Photon activation analysis (PAA) includes extensive data evaluation that is sensitive to error. In order to save time and
minimize human error, a new computer program—photon activation analysis system (PAAS)—was designed, built and implemented
using the SQL language and Asp.net technology to analyze PAA data. Given peak information from PAA spectra and aided by a
photonuclear data library, the program identifies the product isotopes, recognizes the possible nuclear reactions, and evaluates
the concentration of target elements. Uncertainties of concentrations are estimated using standard error propagation techniques.
The program can be accessed conveniently anywhere the internet is available and gives a fast and reliable determination of
the trace elemental content of samples. Furthermore, this program also allow one to search its database for the information
of general photonuclear reactions (e.g. energy lines, line intensities, target and product nuclides, photonuclear reactions,
cross sections, natural abundance, etc.) and estimating the activity even before the activation begins. By switching the nuclide
libraries, the program could also be expanded to neutron activation analysis and charged particle activation analysis (CPAA)
without any difficulty. This program can be a versatile tool for the daily use of the nuclear and radiochemistry laboratories
that conduct activation analysis.
Authors:C. Segebade, M. Hedrich, O. Haase, and B. Baede
Photovoltaic modules are the most promising sources of renewable energy. According to respective EU Directives both the glass
carrier material and the photo-active layer (CdTe in this study) shall be re-used. Analyses for process surveillance and control
have to be carried out, primarily for monitoring of the separation efficiency and the enrichment level of CdTe. For on-site
measurement and process control energy-dispersive X-ray fluorescence spectrometry was used. Instrumental photon activation
analysis using an electron linear accelerator as activating bremsstrahlung source is intended to be used later for iterative
intermediate analysis of random samples for quality control. In this work, the feasibility of both methods for this task was
Authors:D. Schulze, W. Heller, H. Ullrich, H. Kupsch, and C. Segebade
Because of incresing problems due to the general non-acceptance of the application of open radioactivity in modern industrial research an investigation was made concerning the possibility of replacing radiotracers by inactive substances activated by photons after sampling. As an example, investigations in the glass-processing industry was selected. The results were confirmed by the radiotracer experiment performed in parallel. The data obtained were in good agreement.