Further studies on positron lifetimes in γ-irradiated teflon in low dose range
Creators
- 1. Tata Inst. of Fundamental Research, Bombay (India)
Description
Positron lifetime spectra in teflon are measured as a function of γ-dose from 3000 Ci cobalt-60 assembly. The irradiations and positron lifetime measurements are carried out, both in air and vacuum. The values of lifetimes teta1, teta2, teta3 and their respective intensities I1, I2, and I3 are determined with the help of three component fit. Electron spin resonance, density, dielectric constant, and nuclear magnetic resonance measurements are also carried out on teflon samples irradiated in a similar way. Initial γ-dose results in increased free volume of voids, where orthopositronium rests. Hence the lifetime teta3 increases. As the dose is increased further quenching effect of free radicals becomes dominant and lifetime of positronium decreases. Similar trend is observed in dielectric constant and NMR data. (author)
Abstract (German)
Positron lifetime spectra in teflon are measured as a function of γ-dose from 3000 Ci cobalt-60 assembly. The irradiations and positron lifetime measurements are carried out, both in air and vacuum. The values of lifetimes τ1, τ2, τ3 and their respective intensities I1, I2, and I3 are determined with the help of three component fit. Electron spin resonance, density, dielectric constant, and nuclear magnetic resonance measurements are also carried out on teflon samples irradiated in a similar way. Initial γ-dose results in increased free volume of voids, where orthopositronium rests. Hence the lifetime τ3 increases. As the dose is increased further quenching effect of free radicals becomes dominant and lifetime of positronium decreases. Similar trend is observed in dielectric constant and NMR data. Positronenlebensdauern in Teflon werden als Funktion der γ-Dosis von einer 3000 Ci-Cobalt-60-Anordnung gemessen. Die Bestrahlungen und Messungen der Positronenlebensdauer werden sowohl in Luft als auch im Vakuum durchgeführt. Die Werte der Lebensdauer τ1, τ2, τ3 und die entsprechenden Intensitäten I1, I2 und I3 werden mit Hilfe der Dreikomponentenanpassung bestimmt. Elektronenspinresonanz-, Dichte-, Dielektrizitätskonstante- und Kernresonanzmessungen werden an in ähnlicher Weise bestrahlten Teflonproben ebenfalls durchgeführt. Die anfängliche γ-Dosis führt zu einem Anstieg des freien Volumens der Hohlräume, wo Orthopositronium anhaftet. Somit steigt die Lebensdauer τ3 an. Mit steigender Dosis wird ein weiterer Tilgungseffekt der freien Radikale dominierend und die Lebensdauer von Positronium nimmt ab. Ähnliche Trends werden bei der Dielektrizitätskonstante und den NMR-Werten beobachtet.Additional details
Identifiers
Publishing Information
- Journal Title
- Physica Status Solidi (a)
- Journal Volume
- 47
- Journal Issue
- 2
- Series
- Phys. Status Solidi A.
- Journal Page Range
- 691-698
- ISSN
- 0031-8965
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- German Democratic Republic
- INIS RN
- 9415389
- Subject category
- S75: CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY;
- Descriptors DEI
- ANNIHILATION; ELECTRON SPIN RESONANCE; GAMMA RADIATION; IRRADIATION; LIFETIME; NUCLEAR MAGNETIC RESONANCE; PHYSICAL RADIATION EFFECTS; POSITRONS; RADIATION DOSES; TEFLON; VOIDS
- Descriptors DEC
- ANTILEPTONS; ANTIMATTER; ANTIPARTICLES; ELECTROMAGNETIC RADIATION; ELEMENTARY PARTICLES; FERMIONS; INTERACTIONS; IONIZING RADIATIONS; LEPTONS; MAGNETIC RESONANCE; MATTER; ORGANIC COMPOUNDS; ORGANIC FLUORINE COMPOUNDS; ORGANIC HALOGEN COMPOUNDS; ORGANIC POLYMERS; PARTICLE INTERACTIONS; POLYETHYLENES; POLYMERS; POLYOLEFINS; RADIATION EFFECTS; RADIATIONS; RESONANCE
Optional Information
- Notes
- Updated automatically by Metadata and Full-Text Enrichment Agent