J. Kansy1 and M. Ziąbka2
1
Institute of Material Science, Silesian University, Bankowa 12, 40008 Katowice, Poland
2
Faculty of Materials Science and Ceramic, University of Science
and Technology, A. Mickiewicza 30, 30-059 Krakow, Poland
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Positrons emitted from 22Na induce irradiation
damage in polymer - intensity of the longestlived component I3 decreases gradually with the
measurement time.
Small dose of irradiation deposing (~ 1kGy e+ and
102 Gy )– large effect on I3 = I3 (t) (t ~ 10 h)
3 not effected by positron source irradiation
M. Welander and F.H.J. Maurer. Matter. Sci. Forum. 105/110, 1811
(1992)
T. Suzuki at al. Radiat. Phys. Chem. 45, 657 (1995)
Z.L. Peng at al. phys.stat.sol. (a) 155, 299 (1996)
T. Suzuki at al. Radiat. Phys. Chem. 45, 657 (1995)
Z.L. Peng at al. phys.stat.sol. (a) 155, 299 (1996)
Time dependence of the o-Ps intensity I3 in HDPE (crystallinity
57%). Data collected at 300 K. The measurement was discontinued
(sample separated from positron source) at point a) for 10 days, at
point b) – for 2 days, and at point c) – for 17 days – process
partially recoverable
J Kansy and T Suzuki, Radiation
Physics and Chemistry 76 (2007)
759–765
Delayed Formation of Ps (DFP)
J Kansy and T Suzuki, Radiation
Physics and Chemistry 76 (2007)
759–765
J Kansy and T Suzuki, ACTA
PHYSICA POLONICA A 110
(2006) , 593
e+
te+
ortho
p
400 ps
956 ps
2.43 ns
0.511
e+ trapping rate into free volume ()
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The DFP model well described the HDPE lifetime
spectra collected at room temperature
The positronium formation seems to be connected
with positron trapping in free volume at vicinity of
a negative charge
The decrease in efficiency of Ps formation with the
time of measurement (=time of sample irradiation)
is due to scavenging of quasi-free electrons by
free radicals induced by the source irradiation
Address of Website with programs LT9, LT10,
LT Polymer and others:
www.prac.us.edu.pl/~kansy