نویسندگان

چکیده

در این مقاله، ابتدا گزارشی از مشخصات یک سیستم اندازه‌گیری طول عمر نابودی پوزیترون در مواد، که برای اولین بار در ایران با همکاری گروه فیزیک دانشگاه سیستان و بلوچستان و شرکت نوین طیف ساخته شده، ارائه می‌شود. در حال حاضر این سیستم قادر است با قدرت تفکیک زمانی بهتر از 350 پیکوثانیه طول عمر نابودی پوزیترون در موادی همچون سرامیک، شیشه و سایر مواد عایق با ضریب دی الکتریک متفاوت را اندازه‌گیری کند. در ادامه گزارشی از طراحی و راه‌اندازی اولین و تنها سیستم بومی تولید باریکه‌های پوزیترون حرارتی و به‌کارگیری آن در مطالعة عیوب ناشی از تابش‌های پرانرژی در ساختار مواد، ارائه می‌شود. این دستگاه توسط دانشگاه سیستان و بلوچستان و با حمایت مالی طرح‌های نوین وزارت صنعت، معدن و تجارت طراحی و ساخته شده‌است.

کلیدواژه‌ها

عنوان مقاله [English]

Positron Annihilation Spectroscopy in Materials and Technical Details of Measurement Systems

نویسندگان [English]

  • A. A. Mehmandoost-Khajeh-Dad
  • M. Khaghani
  • M. Jafarzadeh-Khatibani

چکیده [English]

Being a very powerful method, Positron Annihilation Spectroscopy (PAS) has been widely used for investigation of defects type and concentration in materials in recent years. In this paper, we first report characteristics of a Positron Annihilation Lifetime Spectroscopy (PALS) system which has been made in an Iranian nuclear spectroscopy instrument company with corporation of Sistan and Baluchestan University for the first time. The system is working with a resolution better than 350ps and can be used for materials such as ceramics, glasses and insulator materials. Next, we report designing and development of the first slow positron beam in Iran and we explain its advantages for exploring defects in materials. Positron Source, moderator and vacuum chamber including positron beam tube and sample chamber, has been designed and prepared. Designing of extraction lenses and magnetic fields has been made using CST STUDIO software in order to optimum focusing and transition of beam.

کلیدواژه‌ها [English]

  • Slow positron beam system
  • Positron annihilation spectroscopy
  • Life time spectroscopy
  1. [1] Paul, D. L. and Saint-Pierre, L., “Rapid Annihilations of Positrons in Polyatomic Gases,” Physical Review Letters,Vol.11, No. 11, 1963, pp.493-496.
  2. [2] Singh J. J., “Microstructural Characterization of Polymers with Positrons”, NASA Langley Research Center, TM-110469, 1996.
  3. [3] Singh, J. J., Pater, R. H. and Eftekhari, A., “Microstructural Characterization of Semi-Interpenetrating Polymer Networks by Positron Life-time Spectroscopy,” NASA Langley Research Center, TP-3617, 1996.
  4. [4] Singh, J. J., Sprinkle, D. R. and Eftekhari, A., “Positron Lifetime Spectroscopy for Investigation of thin Polymer Coatings”, NASA Langley Research Center, TM-4421, 1993.
  5. [5] Semiconductor Device Laboratory Annual Report, “Theoretical and Experimental Studies of Radiation-Induced Damage to Semiconductor Surfaces and the Effects of this Damage on Semiconductor Device Performance”, NASA Grant NsG-588, 1965.
  6. [6] Tuomisto,, Defect Characterization in Semiconductors with Positron Annihilation Spectroscopy, Springer Handbook of Crystal Growth, 2010.
  7. [7] Weiss, A., Koymen, A. R., Mehl, D., Jensen, K. O., Lei, C. and Lee, K. H., “Positron Annihilation Induced Auger Electron Spectroscopy,” NASA Goddard Space Flight Center, CP-3058, 1990, pp. 289-291.
  8. [8] Singh, J. J. and Eftekhari, A., “Investigation of Oxygen-Induced Quenching of Phosphorescence in Photoexcited Aromatxc Molecules by Positron Annihilation Spectroscopy,” NASA Langley Research Center, TP-3619, 1996.
  9. [9] Singh, J. J., Holt, W. H. and Mock, W., “Positron Annihilation Spectroscopy with Magnetically Analyzed Beams,” NASA Langley Research Center, TM-84535, 1982.
  10. [10] Esmizade, E., RazaviNoori, M. and Kalati, V. A., “Positron Annihilation Life-time Spectroscopy (PALS), Introduction and Applications in Polymer Science,” Journal of Educationalpolymerization, Research of the Second Year, No.1, pp. 22-29, 1391.
  11. [11] Abedy, S. and Shirani, A., “Positron Life Time Measurement in Al Using a Coincidence System,” Iranian Physics Conference Proceedings, No. 981,
  12. [12] Nezhad Basaidu, A., GEANT4 Simulation of a Coincidence System for Positron Annihilation Gamma Spectroscopy in Material, (M. Sc. Thesis), University of Sistan & Baluchestan, Jan. 2010.
  13. [13] Khaghani, M., Study of Positron Spectroscopy Methods and Development of Instrumentation for Doppler Broadening Technique, ( Sc. Thesis), University of Sistan & Baluchestan, Jan.2010.
  14. [14] Nikoo, H., Simulation of 22Na Positron Source Producing with Proton Beam below 30 MeV Energies in MCNPX, (M. Sc. Thesis), University of Sistan & Baluchestan, Feb. 2012.
  15. [15] Shamsaddiny-Lory, S., “Positron Annihilation Life-time Spectroscopy of Bulk Samples and Operating the Set-up,” (M. Sc. Thesis), University of Sistan & Baluchestan, Feb. 2012.
  16. [16] Fattah-Moghadam-Talemi, L., Experimental Study of Wolfarm as a Positron Moderator, (M. Sc. Thesis), University of Sistan & Baluchestan, Feb. 2012.
  17. [17] Mohammadi-Dadkan, M., Calculation the Technical Details and Design a Bending Magnetic Transmission System for Transfer Slow Positron, (M. Sc. Thesis), University of Sistan & Baluchestan, Jan. 2013.
  18. [18] Puska, M. J. and Nieminen, R. M., “Theory of Positrons in Solids and on Solid Surfaces,” Reviews of Modern Physics, Vol. 66, No. 3, 1994, p. 841.
  19. [19] Krause-Rehberg, R. and Leipner, H. S., Positron Annihilation in Semiconductors, Springer-Verlag Berlin Heidelberg New Yourk, 1999.
  20. [20] Mehmandoost-Khajeh-Dad A. A., Mahjour-Shafiei, M. and Khaghani, M., “Development of a Doppler Broadening Positron Spectroscopy Setup and Relative Positron-Electron Momentum Distribution Measurement for Commercial Al,” Journal of Theorical and Applied Physics, Vol. 4, No. 4, 2011, pp. 9-12.
  21. [21] West, R. N., et.al, Positron in Solids, Edition P. Hautojarvi, Springer, Heidelberg, 1979.
  22. [22] Vehanen, A., Lynn, K. G., Schutz, P. J. and Eldrup, M., “Improved Slow-Positron Yield Using a Single Crystal Tungsten Moderator,” Applied Physics  A., Vol. 32, No. 3, 1983, p. 163
  23. [23] Stavola, M., Identification of Defects in Semi-Conductors, Academic Press, 1998.
  24. [24] Rohatgi, A., et. al, “A Review of Selected Techniques for Characterizing Radiation-Induced Defects in Solar Cells,” Solar Cells, Vol. 31, No. 4, 1991, pp. 379-394.
  25. [25] D. C. and West. R. N., “Positron Annihilation and Defects in Metals,” Physical Letter A, Vol. 30, No.1, 1969, p. 24.