THE ROLE OF THERMAL HISTORY ON POSITRONIUM FORMATION AT LOW TEMPERATURE STUDIED BY POSITRON ANNIHILATION LIFETIME SPECTROSCOPY
DOI:
https://doi.org/10.53808/KUS.2010.10.1and2.1008-EKeywords:
Positronium, Positron annihilation lifetime spectroscopy, Positronium formation, Orthopositronium, High density polyethyleneAbstract
Thermal history dependence of positronium formation at low temperature has been studied on high density polyethylene (HDPE) by positron annihilation lifetime spectroscopy (PALS). The study shows that the ortho-positronium formation at low temperature depends on both the temperature and thermal history. Two temperature studies of positron formation have been performed. The first study orthopositronium (o-Ps) formation were measured at 20, 40, 60, 80, 120, 150 and 200 K. In the second one the same measurement was performed during heating through the same temperature after passing through a low temperature of 20 K. It has been found that the time saturated values of intensity (I3) of o-Ps at each temperature after passing through 20 K were generally higher than that of obtained by direct cooling at the same temperature. This result has been explained on the basis of o-Ps formation mechanism and structural change of polymer with temperature.
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He, C., Suzuki, T., Shantarovich, V.P., Ma, L., Matsuo M., Kondo, K. and Ito, Y. 2003. Positronium formation in low-density polyethylene. Physics Letters, A 313: 223-230
Hirade, T. 2003. Positronium formation in low temperature polymers. Radiation Physics and Chemistry 68: 375-379
Hirade, T., Maurer, F.H.J. and Eldrup, M. 2000. Positronium formation at low temperatures: the role of trapped electrons. Radiation Physics and Chemistry 58: 465-471
Kansy, J. and Suzuki, T. 2007. Delayed formation and localisation of positronium in polymers at low temperatures. Radiation Physics and Chemistry 76: 759-765
Kindl, P. and Reiter, G. 1987. Investigation on the low temperature transitions and time effect of branched poyethylene by the positron lifetime technique. Physica status solidi, A 104: 707-713
Levay, B., Lalovic, M. and Ache, H.J. 1989. Solid-solid phase transition and molecular motion in ling chain paraffin studied by positron annihilation techniques. Journal of Chemical Physics 90: 3282-3291
Stepanov S.V. and Byakov, V.M. 2002. Electric field effect on positronium formation in liquid. Journal of Chemical Physics 116 (14): 6178-6195
Suzuki,T., He, C., Shantarovich, V., Kondo, K., Ito,Y., Ma, L. and Matsuo, M. 2003. Relaxation behaviour of polymers probed by positron annihilation lifetime spectroscopy. Materials Research Innovations 7 (1): 31-36
Suzuki, T., Ito, Y., Kondo, E., Hamada, and Ito, Y. 2000. Radiation effect on positronium formation in low-temperature polyethylene. Radiation Physics and Chemistry 58: 485-489
Uedono, A., Kawano, T., Tanigawa, S., Ban, M., Kyoto, M. and Uozumi, T. 1997. Transition and Relaxation Process of polyethelene, polypropylene and polystyrene studied by positron annihilation. Journal of Polymer Science, B 35: 1601-1609
Wang, C.L., Hirade T., Maurer, F.H.J., Eldrup, M. And Pedersen, N.J. 1998. Free-volume distribution and positronium formation in amorphous polymers: Temperature and positron-irradiation-time dependence. Journal of Chemical Physics 108 (11): 4654-4661
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