Collection of Ions Produced by Alpha Particles in Air

Abstract

In the measurement of the ionization caused by alpha particles in air, recombination effects between slowly moving positive and negative ions (the latter formed by electron attachment to oxygen) have to be considered. The usual procedure in such measurements is to determine the saturation current (by extrapolation of reciprocal current versus reciprocal voltage curves to infinite field strength) according to the Jaffe theory. A paper by Wingate, Gross, and Failla has cast doubt on the validity of this extrapolation technique, in that the authors propose a field-independent part of the recombination amounting to 3.3% at atmospheric pressure in air. This proposal implied that all previous measurements of W a for air were in error by this amount and that this error is a possible cause for the reported difference (3-4%) between W values for alpha and beta particles in air. In view of our own W measurements we felt compelled to reexamine this supposedly field-independent part of the recombination. Approximating the experimental conditions of Wingate, Gross, and Failla we have not been able to reproduce their effect and our experiments demonstrate the validity of the usual extrapolation techniques.

Water at interfaces and its influence on the electrical properties of adsorbed films

“…Therefore, the higher the humidity level the higher ionization is. The X-ray beam energy used here (∼7.10 5 Kcal/mol) can break water molecules (492 Kcal/mol), NH−−N hydrogen bonds (∼10 Kcal/mol) [90], and ionize chemical species in the atmosphere studied (749 Kcal/mol for oxygen, 853.6 Kcal/mol for nytrogen, 621 Kcal/mol for argon, 800 Kcal/mol for CO 2 , and 818.8 Kcal/mol for dry air [91][92][93]). There is also the possibility of indirect formation of ionic species due to interactions between X-ray photons and gases or polyaniline molecules.…”

Filmes de Langmuir e Langmuir-Blodgett de Polianilinas

“…Quando partículas de alta energia atravessam a matéria, elas causam o fenômeno de ionização ao longo do caminho que percorrem. A energia gerada pelo feixe de raios-X (~7.10 5 Kcal/mol) em nossos experimentos é suficiente para quebrar as moléculas de água (492 Kcal/mol), as ligações de ponte de hidrogênio do tipo N-H---N (~10 Kcal/mol) [ [104] consideraram efeitos de recombinação no processo de ionização do ar por raios-X, encontrando um valor de 738,9 Kcal/mol. Para a criação de um par iônico são necessárias 476,8 Kcal/mol.…”