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Further studies of a ferrous iron doped synthetic kaolin: dosimetry of X-ray induced defects

Published online by Cambridge University Press:  09 July 2018

Abstract

The structure of kaolin has been examined together with aspects of dosimetry and energy loss mechanisms of radiation to explain the formation of g = 2 EPR centres. The analysis points to the formation of a trapped hole on the ‘inner layer’ oxygen atoms of kaolin located at the boundaries between divalent ion and trivalent ion ‘cells’, in particular at the boundaries with excess negative charge. Direct interaction of X-rays with atoms and the possibility of proton recoil are eliminated. The means of production appears to be by transfer of charge following ionization of atoms by secondary electrons, with transfer of vacancies ultimately to the oxygen ions. Mechanisms which result in a decrease in signal strength with increase in concentration are examined. It is concluded that the cell mechanisms discussed are consistent with the rates of production and that at 20 Mrad (air) the number of centres should be reaching saturation.

Résumé

Résumé

La structure du kaolin a été examinée en même temps que divers aspects de la dosimétrie et de mécanismes de perte d'énergie des radiations en vue d'expliquer la formation de centres RPE avec g = 2. Cette analyse indique la formation de trous piégés dans le ‘plan interne’ des atomes d'oxygène du kaolin situés à la limite entre des ‘mailles’ contenant des ions bivalents et trivalents. Ces trous existent en particulier à toutes les limites portant une charge excédentaire négative. On a éleminé l'interaction directe entre rayons X et atomes, et la possibilité du recul du proton. Les modes de formation semblent être un transfert de charge, suivi de l'ionisation des atomes par des électrons secondaires, avec finalement un transfert des vides sur les ions oxygène. On examine les mécanismes qui entraînent la diminution de l'intensité du signal lors de l'accroissement des concentrations. On conclut que les mécanismes de maille qui ont été proposés sont en accord avec les vitesses de production et que sous 20 Mrad (air) le nombre de centres doit atteindre la saturation.

Kurzreferat

Kurzreferat

Die Struktur von Kaolin wurde zusammen mit Aspekten von Dosierung und Mechanismen des Verlustes von Strahlungsenergie untersucht, um die Bildung von g = 2 EPR Zentren zu erklären. Die Analyse weist aufeine Bildung von eingeschlossenen Hohlräumen bei den ‘Innenlagen’ der Kaolin-Sauerstoffatome hin, die an den Grenzzonen zwischen di- und trivalenten ‘Ionenzellen’, insbesonders an den Grenzen mit negativem Ladungsüberschuß lokalisiert sing. Eine direkte Wechselwirkung der Röntgenstrahlen mit Atomen und die Möglichkeit des Protonenrückstosses ist ausgeschlossen. Der Vorgang der Entstehung scheint eine Ladungsübertragung zu sein, die der Atomionisierung durch sekundäre Elektronen folgt und wobei letztlich die Leerstellen auf die Sauerstoffionen übertragen werden. Es werden die Mechanismen untersucht, welche aufeinen Abfall der Signalstärke bei gleichzeitigem Häufigkeitsanstieg hinauslaufen. Es wird der Schluß gezogen, daß die diskutierten Zell-Mechanismen mit den Produktionstraten übereinstimmen und ferner die Anzahl der Zentren bei 20 Mrad (Luft) einen Sättigungsbereich erreicht haben dürften.

Resumen

Resumen

Se ha examinado la estructura del caolín junto con aspectos de dosimetría y mecanismos de pérdida de energía de radiación, para explicar la formación de centros paramagnéticos con g = 2. El análisis parece indicar la formación de un hueco atrapado sobre la ‘capa interna’ de átomos de oxigenos del caolín, localizado en los bordes entre ‘octaedros’ con ión trivalente y divalente, en particular, en los bordes con exceso de carga negativa. La interacción directa de rayos X con los átomos y la posibilidad de retroceso protónico han sido eliminadas. El proceso de formación parece ser la transferencia de carga que sigue a la ionización de átomos por electrones secundarios, con transferencia final de vacantes a los átomos de oxigeno. Se discuten mecanismos que se traducen en una disminución de la fuerza de la señal con el aumento de concentración. Se concluye que los mechanismos discutidos son consistentes con las velocidades de formación y que a 20 Mrd (aire) el número de centros debería llegar a la saturación.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1981

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References

Angel, B.R. & Hall, P.L. (1972) Electron spin resonance studies of kaolins. Proc. Int. Clay Conf. Madrid, 4760.Google Scholar
Angel, B.R., Jones, J.P.E. & Hall, P.L. (1974) Studies of doped synthetic kaolinite I. Clay Miner. 10, 247256.CrossRefGoogle Scholar
Angel, B.R., Cuttler, A.H., Richards, K.S. & Vincent, W.E.J. (1977) Synthetic kaolinites doped with Fe2+ and Fe3+ ions. Clays Clay Miner. 25, 381383.CrossRefGoogle Scholar
Bergström, I. & Nordling, E. (1965) The Auger effect. Pp. 15231543 in: Handbook of alpha-, beta- and gamma-ray spectroscopy, Vol. 2 (Siegbahn, K., editor). North Holland Publishing Company, Amsterdam, Holland.Google Scholar
Cuttler, A.H. (1980) The behaviour of a synthetic 57Fe-doped kaolin: Mössbauer and electron paramagnetic resonance studies. Clay Miner. 15, 429444.CrossRefGoogle Scholar
Davisson, C.M. (1965) Interaction of gamma-radiation with matter. Pp3778 in: Handbook of alpha-, beta- and gamma-ray spectroscopy, Vol 1. (Siegbahn, K., editor). North Holland Publishing Company, Amsterdam, Holland.Google Scholar
Fripiat, J.J., Bosmans, H. & Rouxhet, P.G. (1967) Proton mobility in solids I; hydrogen vibration modes and proton delocalisation in boehmite. J. Phys. Chem. 71, 10971111.CrossRefGoogle Scholar
Hägstrom, S., Nordling, C. & Siegbahn, K. (1965) Electron binding energies and kinetic energy against magnetic rigidity. Pp.845862 in:Handbook of alpha-, beta- and gamma-ray spectroscopy, Vol. 1. (Siegbahn, K., editor). North Holland Publishing Company, Amsterdam, Holland.Google Scholar
Grodstein, G.W. (1957) Attenuation coefficients from 10 keV to 100 MeV. U.S. National Bureau of Standards Circular 583. Washington, USA.Google Scholar
Herbillon, J.A., Mestdagh, M.M., Vielvoye, L. & Derouane, E.G. (1976) Iron in kaolinite from tropical soils. Clay Miner. 11,201220.CrossRefGoogle Scholar
Jones, J.P.E., Angel, B.R. & Hall, P.L. (1974) Studies of doped synthetic kaolinites II. Clay Miner. 10,257270.CrossRefGoogle Scholar
Knop, G. & Paul, W. (1965) Interaction of electrons and alpha particles with matter. Pp136 in:Handbook of alpha-, beta- and gamma-ray spectroscopy, Vol. 1 (Siegbahn, K., editor). North Holland Publishing Company, Amsterdam, Holland.Google Scholar
McGinnies, R.T. (1959) X-ray attenuation coefficients from l0 keV to 100 MeV U.S. National Bureau of Standards Supplement to Circular 583. Washington, USA.Google Scholar
Marshall, J.S. & Ward, A.C. (1957) Absorption curves and ranges for homogeneous beta-rays. Can. J. Research 15A, 3941.CrossRefGoogle Scholar
Meads, R.E. & Malden, P.J. (1975) Electron spin resonance in natural kaolinites containing Fe3+ and other transition metal ions. Clay Miner. 10, 313346.CrossRefGoogle Scholar
Snell, A.H. (1965) Atomic and molecular consequences of radioactive decay. Pp15451555 in: Handbook of alpha-, beta and gamma-ray spectroscopy, Vol. 2 (Siegbahn, K., editor). North Holland Publishing Company, Amsterdam, Holland.Google Scholar
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Further studies of a ferrous iron doped synthetic kaolin: dosimetry of X-ray induced defects
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