Positron Irradiation Effects on Positronium Formation in Polycarbonate Sduring a Positron-Annihilation Experiment

• Authors: T. Suzuki , K. Kondo , E. Hamada , Y. Ito
• Languages of publication: EN

Abstracts

EN

The positron-irradiation effect on polycarbonate during a positron-annihilation lifetime spectroscopy experiment was investigated using different intensities of ^{22}Na positron sources andγ-irradiated samples. The decrease in I_3 was larger for a larger intensity of positron sources. In the case of a weak source (≈ 140 kBq), I_3 did not change with the elapsed time for non-irradiated samples. However, for 1 MGy irradiated samples, I_3 measured with the weak source increased with the elapsed time. This can be attributed to a decrease in the radicals induced in the irradiated samples by γ-irradiation. In order to explain the change in I_3 measured at room and liquid-nitrogen temperatures, several effects, such as radicals, cross-linking, structure change, and charging, need to be considered. Also, it is difficult to explain the change in I_3 using only one of these effects.

Keywords

EN

78.70.Bj

Discipline

• 78.70.Bj: Positron annihilation(for positron states, see 71.60.+z in electronic structure of bulk materials; for positronium chemistry, see 82.30.Gg in physical chemistry and chemical physics)

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2001
• Volume: 99
• Issue: 3-4
• Pages: 515-521

Dates

published

2001-03/04

received

2000-09-18

Contributors

author

T. Suzuki

• High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan

author

K. Kondo

• High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan

author

E. Hamada

• Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ami, Ibaraki 300-0394, Japan

author

Y. Ito

• Research Center for Nuclear Science and Technology, The University of Tokyo, Tokai, Ibaraki 319-1106, Japan

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Identifiers

DOI

10.12693/APhysPolA.99.515