Charged particle activation analysis coupled with X-ray counting

A survey is given on the analytical use of X-ray emitting radioisotopes produced by charged particle activation. Thirty-nine proton and deuteron reactions were considered on twentysix elements (34≤Z≤82). Thick target yields and sensitivity estimates are presented. The features and limitations of this method and the scope of non-destructive and destructive determinations are discussed. The main interest of this approach is to open an avenue for trace analysis with simplified data acquisition and reduction.     

On the application of charged particle activation analysis to the trace characterization of semiconductor materials

Résumé 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 co?ncidence 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.      

Analysis of Fluorescent Proteins with a Nanoparticle Probe

This letter presents the first application of high energy, single nanoparticle probes (e.g., 520 keV Au(400) 2nm NP) in the characterization of surfaces containing fluorescent proteins (e.g., GFP variants) by their co-emitted photon, electron and secondary ion signals. NP induced protein luminescence increases with the NP incident energy, is originated by the NP impact and is transferred to the protein fluorophor via electronic energy transfer. Multi-electron emission is observed per single NP impacts and their distributions are specific to the target morphology and composition. Fragment ions of protein sub-units consisting of 2-7 amino acid peptides are observed under individual NP impacts that can be correlated to the random protein orientation relative to the impact site (e.g., outer layer or "skin" of the protein).     

Heavy ion induced K,L and M X-rays and their use in trace element analysis

Characteristic K, L and M X-ray and background production trends from high energy heavy ion bombardment were investigated on a series of target elements (14≤Z≤92) using 0.5 MeV/amu and 1 MeV/amu Nⁿ⁺, Oⁿ⁺, Cuⁿ⁺, Krⁿ⁺ and Xeⁿ⁺ beams. X-ray production for K and L shell X-rays roughly followed the same trends, i.e. increased yield with projectile size and energy and decreased yield with increasing X-ray energy. Broad simultaneous multielement coverage can be achieved using K, L and M Lines. Experimental detection limits of 0.8 to 10 ppm were obtained for elements between Mn and Se with K X-ray detection, between Sm and Pb using L X-ray detection, and for Th and U via M X-ray detection in biological samples with a 1MeV/amu Kr⁷⁺ beam of 70 nA for 1000 s. These detection limits are better for many elements than those obtained with a 1.65 MeV proton beam.     

Studies in heavy ion activation analysis

¹⁸O induced radioactivation may be used for the trace detection of¹H via¹H (¹⁸O, n)¹⁸F. Matrices in which this reaction is interference-free include: Al, Si, S, K, Ti, V, Ni, Cu and Zn. However, due to numerous radioisotopes created at the bombarding energies used (E≥51 MeV), a post-irradiation chemical separation of¹⁸F is required.¹⁸O activation also appears as a promising means for the trace determination of S[S(¹⁸O, x)⁴⁷V], Si[Si(¹⁸O, x)^43–44Sc] and B[B(¹⁸O, x)³⁷Mg]. Part I: in Journal of Radioanalytical Chemistry, 53 (1979) 181.     

Microanalysis of “biometallic” compounds using nuclear and atomic activation

A novel method for the characterization of metal containing biological compounds has been developed which utilizes both nuclear activation [e.g.,¹²C(³He, α)¹¹C] and atomic activations (X-ray emission) induced by 8 MeV³He bombardment. Detection limits for carbon (≈1 μg), oxygen (≈1μg), and metals (1 to 10 ng for elements between P and Zn) were obtained under routine experimental conditions. The metal stoichiometry of six different compounds (alkaline phosphatase, amylase, carbonic anhydrase, diamine oxidase, my oglobin, vitamin B₁₂) were determined with typical relative precisions of ±25% for a 40 μg sample. A comparison of these ratios with carbon and metal measurements obtained by other methods showed a relative accuracy of 1 to 20%.