Authors:J. Mcginley, L. Žikovský, and E. Schweikert
The use of heavy ion activation as a method for the analysis of hydrogen and deuterium has been evaluated. Thick target yields
from reactions of7Li,10B,11B and19F on1H and2H have been determined; activation curves for many of these reactions are presented and interferences are evaluated. Hydrogen
has been determined in titanium via1H(10B, α)7Be at the 100 and 33 ppm levels with relative precisions of 8 to 10%.
Authors:R. Wainerdi, R. Zeisler, and E. Schweikert
Capabilities of 14 MeV neutron activation analysis with a high output generator are evaluated and found to be comparable with
conventional activation analysis regarding sensitivity and precision; additional elements are instrumentally accessible at
trace levels. Nuclear reactions featuring higher selectivity are listed and their sensitivity is compared to the present state
of 14 MeV activation. Quasi-promt activation (T<1 sec) expands the scope of the technique to rapid nondestructive assays of
trace species in bulk samples.
A procedure for measuring trace amounts of Li and Be in different types of samples has been studied using a 12.5 MeV14N beam. At this energy the principal nuclear reactions are6Li(14N, d)18F,7Li(14N, t)18F, and9Be(14N, αn)18F. Detection limit for destructive analysis for either beryllium or lithium has been calculated at 300 ppb with a determination
limit of 5 ppm for an irradiation with a beam of 1 μA·h/cm2. Destructive analysis was performed on CANMET SY-2 and USGS BCR-1 (rock samples 1–10 ppm Be). Non-destructive analysis for
beryllium and lithium was performed on NBS SRM 610 (500 ppm trace element glass), NBS 612 (50 ppm trace element glass), and
NBS SRM 181 (Spodumene ore, 6.4% Li2O). Detection limit of 2 ppm has been calculated for nondestructive analysis of either lithium or beryllium.
Authors:A. Sanni, N. Roché, H. Dowell, E. Schweikert, and T. Ramsey
Carbon and oxygen impurities in silicon have been determined by 7.00 MeV3He activation analysis. The detection limits obtained for interference-free conditions are 0.1 ppb (wt) for carbon and 1.0 ppb (wt) for oxygen in silicon.
Authors:S. Dabney, D. Swindle, J. Beck, G. Francis, and E. Schweikert
An analytical method is described for the determination of trace amounts of sulfur by charged particle activation analysis.
The method consists of proton irradiation followed by a rapid radiochemical separation of the product nuclide,34m Cl. This procedure has been applied to a number of pure metal samples which range in sulfur content from 0.3 to 30 ppm. All
analyses were repeated several times to ensure consistent results and to better evaluate experimental detection limits and
systematic errors. The results indicate that sulfur determinations can be performed at a concentration of less than 1.0 ppm.
Activation curves are presented for the reactions S(d,x)34mCl, S(p,x)34mCl, and the interfering reaction35Cl(p, pn)34mCl.
Authors:J. Welsh, W. James, E. Schweikert, and H. McWhinney
This paper describes first the application of neutron depth profiling (NDP) for measuring the distribution of6Li in LiAlO2 ceramics. Using a surface barrier detector for detecting3H produced in6Li(n, )3H,6Li was profiled to a depth of 14 m in the ceramics. Secondly, a new methodology is presented for NDP with enhanced capabilities based on measuring the energy of recoiling nuclei from (n, p) and (n, ) reactions by time-of-flight mass spectrometry. The scope of recoil nucleus time-of-flight mass spectrometry (RN-TOF-MS) includes profiling of10B,14N,17O,33S,35Cl,40K. Probe depths may be of a few tens nanometers. RN-TOF-MS complements and refines NDP based on charged particle (p or ) spectrometry.
Authors:E. Schweikert, J. McGinley, G. Francis, and D. Swindle
On décrit l'application de l'analyse par activation aux particules chargées (AAPC) avec mesure après irradiation à la détection
de traces d'oxygène, de bore et de lithium. On utilise l'activation aux protens, aux alpha et aux3He pour le dosage non-destructif de l'oxygene dans le silicium. Les limites de détection expérimentale sont respectivement
de 0,06 ppm, 0,05 ppm et 5 ppb. L'activation aux3He, couplée à une séparation radiochimique après irradiation, a été employée pour les analyses de l'oxygène dans le germanium
avec une limite de détection de 10 ppb. De nouvelles techniques ont été développées pour le dosage du bore et du lithium,
basées sur la mesure du8Li (T: 850 msec) et de12B (T: 20 msec), respectivement et utilisant une technique de mesure β en coïncidence avec deux scintillateurs minces de plastique.
Les possibilités de cette méthode presque “prompte” sont illustrées avec des résultats concernant le silicium, le germanium
et des échantillons de verre.
Authors:J. Poland, S. Kormali, W. James, and E. Schweikert
The feasibility of charged particle activation analysis for phosphorus measurements was evaluated. Several nuclear reactions were studied with respect to pertinent activation data, thick target yields for calibration, relative excitation functions, and quantitative importances of interferences. Determination of phosphorus by the reaction31P(,n)34mCl was determined to be most advantagous with sensitivity competitive with other techniques.