Modern technology produces a large variety of organic, metallo-organic and inorganic compounds which might be analysed successfully for their stoichiometry by INAA or IPAA if the error sources are kept under control. The problems of comparator materials, irradiation by linear accelerator, measurement and data evaluation including minor corrections are dealt with. Application to TiCN, Si3N4, SiC and nitrogen determination in different carbonaceous materials is reported.
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:G. Wermann, W. Goerner, D. Gawlik, and D. Alber
A new application of neutron transmutation doping is described. The method is useful to prepare graded zinc contents in highly pure copper materials. The research reactor BER II at the Hahn-Meitner-Institute, Berlin served as a neutron source. The zinc content produced in the samples was analyzed by determining the 65Zn-activity via gamma-spectrometry. Simultaneously irradiated flux monitors were used to determine the neutron flux density. Since cylindrical sample geometries are favorable for a reference material application in optical emission (OE) spectroscopy, the spatial distribution of the induced activity in a cylinder with a diameter of 8 mm and a length of 35 mm was investigated.
Authors:W. Goerner, O. Haase, M. Ostermann, and Chr. Segebade
C, N, O, F and P can be analyzed by instrumental photon activation analysis (IPAA) including decay curve analysis. The interference
of 30P (T1/2 = 149.9 s) by 15O (T1/2 = 122.2 s) can be ruled out by direct positron measurement making use of the largely different maximum β+-energies of both nuclides (3.24 MeV and 1.73 MeV, respectively). Interference by carbon (11C) can be avoided by sub-threshold activation with 17 MeV bremsstrahlung. The short half-life of 30P allows a high productivity of the method. Reliability was demonstrated in the range of 0.2%–2% P (detection limit = 40 μg/g).
Analysis of a certified reference material (BCR-CRM 063) yielded excellent agreement with the certified data.
Authors:W. Goerner, B. Noll, H. Spies, and K. Thieme
The Tc budget in several ROTOP-generators was determined by neutron activation analysis (NAA) and UV-spectroscopy. The complete procedure included the preparation of the generator, elution cycle in 24 to 72 h intervals and evaporation of the eluates to dryness. The samples were aliquoted, irradiated in the reactor and analyzed via99Tc(n, n')99mTc
99Tc reaction as well as by UV-absorption due to pertechnetate. The most reliable method proved to be NAA including chemical separation from24Na by ion exchange after the complete decay of38Cl. The detection limit was 50 ppb (3 ng Tc), compared with the total amount of several 10–5 g down to 10–7 g Tc in the system and its fractions. The mass balance and the elution profiles obtained correspond very well to the theoretical values. The results permit further quantitative considerations on both elution kinetics and the generator system.