Beiträge zur Mikrobestimmung von Kohlenstoff-14 und Tritium

Die Verwendung Con¹⁴C und Tritium zur Lösung kinetischer und analylischer Probleme erfordert zuverlässige Analysenmethoden. Es wird iiber die Herstellimg von Meβgasen durch Naβcerbrennung mil Chromsäure-Jodsäure-Gemischen, Trockenverbrennung in Gegenwart Con Katalysatoren wie Kupferoxid, Kobaltoxid und Zersetzungsprodukte des Silberpermanganats und durch Umsetziingentm geschlossenen Rohr berichtet. Die Aktivitätsniessungen erfolgten auf cerschiedene IVeise. Hier werden besonders die Ergebnisse diskutiert, die durch Ionisationskammermessungen erzielt wurden. Schlieβlich werden einfache Apparaturen zur routinemäβigen Durchfiihrung von Mikroanalysen beschrieben.     

Modified Preparation of 99mTe-Iron Hydroxide Macroaggregate (99mTe-Fe-(OH)2MA)

A modified method for preparing ^99mTc-FHMA for pulmonary studies is elabrated. It includes a new antioxidant sodium metabisulphite. The optimum conditions for the reparation are given. A simple and rapid procedure with a yield more than 98% is described which eliminates a further purification step.     

10 Jahre Ständige Kommission des RGW für die friedliche Anwendung der Atomenergie

0. Einleitwng

1. Reaktorwissenschaft und -technik und Kernenergetik

2. Kerntechnischer Gerätebau

3. Produktion von Isotopenerzeugnissen

4. Strahlenschulz und Schutztechnik

5. Isotopenanwendung

6. Strahlentechnik

7. Zur weiteren Tätigkeit der Ständigen Kommission Atomenergie des RGW     

Reaktion von Pyridin-2-Carbonsäure Mit Tetrabutylammonium-Tetrachloro-Nitridotechnetat(VI) Sowie Tetrabutylammonium-Tetrachlorooxotechnetat (V)

Abstract

The reaction of 2-pyridine carboxylic acid (Hpic) with (n-Bu₄N)[TcNCl₄] and (n-Bu₄N)[TcOCl₄] in ethanol and methanol, respectively, yields the dinuclear μ-oxo complex [(pic)₂NTc-O-TcN(pic)(Hpic)Cl] and the monomeric complex [TcO(pic)₂Cl].

Visible and infrared spectroscopy, ESR, ¹H-NMR and ⁹⁹Tc-NMR have been used to characterize the new compounds. The most important field of application for the new compounds synthesized is radiodiagnostics.     

Precise Radiometry: Some Recent Aspects of Fruitful Interaction with Atomic Physics

Modern radiometric analytics demands a complex consideration of nuclear and electron shell processes, if more pretentious aims are envisaged. As an example the small variation of decay rates of radionuclides presents possibilities for information on chemical situations of decaying atoms. In principle this phenomenon is well known since many years, but now the situation is such that, e.g. in ^99mTc internal conversion, a full agreement of the difficult experiments and the respective theory was established. The secondary emission of X-rays as a consequence of high excitation of electron shells in combination with nuclear transitions supplies another example for a methodical progress of radiometry. Investigations on ⁵¹Cr as an electron capture nuclide have shown that chemically induced variations of the K_α to K_β X-ray intensity ratio is at least qualitatively understood.     

Binary collision simulations of ion transmission through silicon single crystal films

Abstract

Computer simulation studies of the energy distribution of transmitted ions such as alpha-particles, He-, and B-ions through crystalline silicon, using the enhanced binary-collision cascade simulator MARLOWE, will be reviewed. The enhancement includes an additional electronic-energy loss (EEL) model which takes into account explicitly both the target electron density variation via the structure factors and the electron density of the projectile. Investigations of the stopping power for He ions and protons in silicon, at intermediate- and high-energies, based on the adapted EEL model and a velocity-dependent effective charge will be presented. The overall agreement between the calculated and experimentally determined stopping power data and the simulated and measured transmission spectra will be demonstrated. Effects of energy-loss straggling, core-electron contribution to the energy loss at high-energies and charge-state effects at low energies on the transmission spectra will also be discussed.     

Measurement of lattice damage caused by ion-implantation doping of semiconductors†

Two new techniques have been used to measure the lattice damage produced in gallium arsenide by the implantation of 60 keV cadmium ions. In one of these methods, optical reflection spectra of the ion-implanted samples were measured in the wavelength range from 2000 to 4600Å. The decrease in reflectivity resulting from ion- implantation was used to determine the relative amount of lattice damage as a function of ion dose. The second technique employed the scanning electron microscope. Patterns very similar in appearance to Kikuchi electron diffraction patterns are obtained when the secondary and/or backscattered electron intensity is displayed in the scanning electron microscope as a function of the angle of incidence of the electron beam on a single crystal surface. The degradation of these ‘Coates-Kikuchi’ patterns resulting from ion implantation was used to obtain a quantitative measure of the lattice damage caused by the implantation process. The results of measurements made by both of the methods described have been compared with each other, and with data obtained by the more established method of measuring lattice damage by Rutherford scattering of 1 MeV helium ions.     

Estimation of isotropic nuclear magnetic shieldings in the CCSD(T) and MP2 complete basis set limit using affordable correlation calculations

A linear correlation between isotropic nuclear magnetic shielding constants for seven model molecules (CH₂O, H₂O, HF, F₂, HCN, SiH₄ and H₂S) calculated with 37 methods (34 density functionals, RHF, MP2 and CCSD(T)), with affordable pcS‐2 basis set and corresponding complete basis set results, estimated from calculations with the family of polarization‐consistent pcS‐n basis sets is reported. This dependence was also supported by inspection of profiles of deviation between CBS estimated nuclear shieldings and shieldings obtained with the significantly smaller basis sets pcS‐2 and aug‐cc‐pVTZ‐J for the selected set of 37 calculation methods. It was possible to formulate a practical approach of estimating the values of isotropic nuclear magnetic shielding constants at the CCSD(T)/CBS and MP2/CBS levels from affordable CCSD(T)/pcS‐2, MP2/pcS‐2 and DFT/CBS calculations with pcS‐n basis sets. The proposed method leads to a fairly accurate estimation of nuclear magnetic shieldings and considerable saving of computational efforts. Copyright © 2013 John Wiley & Sons, Ltd.