Slow positron beam at the JINR, Dubna

• Autorzy: Horodek P. , Kobets A. G. , Meshkov I. N. , Sidorin A. A. , Orlov O. S.

Identyfikatory

DOI

10.1515/nuka-2015-0130

• Konferencja: Polish Seminar on Positron Annihilation (42 nd ; 29.06-01.07.2016 ; Lublin, Poland)
• Języki publikacji: EN

Abstrakty

EN

The Low Energy Positron Toroidal Accumulator (LEPTA) at the Joint Institute for Nuclear Research (JINR) proposed for generation of positronium in flight has been adopted for positron annihilation spectroscopy (PAS). The positron injector generates continuous slow positron beam with positron energy range between 50 eV and 35 keV. The radioactive 22Na isotope is used. In distinction to popular tungsten foil, here the solid neon is used as moderator. It allows to obtain the beam intensity of about 105 e+/s width energy spectrum characterized by full width at half maximum (FWHM) of 3.4 eV and a tail to lower energies of about 30 eV. The paper covers the characteristic of variable energy positron beam at the LEPTA facility: parameters, the rule of moderation, scheme of injector, and transportation of positrons into the sample chamber. Recent status of the project and its development in the field of PAS is discussed. As an example, the measurement of the positron diffusion length in pure iron is demonstrated.

Słowa kluczowe

EN

positron beam; positron injector

• Wydawca: Institute of Nuclear Chemistry and Technology
• Czasopismo: Nukleonika
• Rocznik: 2015
• Tom: Vol. 60, No. 4, part 1
• Strony: 725--728
• Opis fizyczny: Bibliogr. 12 poz., rys.

Twórcy

autor

Horodek P.

• Joint Institute for Nuclear Research, 6 Joliot Curie Str., 141980 Dubna, Moscow region, Russian Federation
• Institute of Nuclear Physics of the Polish Academy of Sciences, 152 Radzikowskiego Str., 31-342 Kraków, Poland

autor

Kobets A. G.

• Joint Institute for Nuclear Research, 6 Joliot Curie Str., 141980 Dubna, Moscow region, Russian Federation
• Institute of Electrophysics and Radiation Technologies NAS of Ukraine, 28 Chernyshevsky Str., 61002 Kharkov, Ukraine

autor

Meshkov I. N.

• Joint Institute for Nuclear Research, 6 Joliot Curie Str., 141980 Dubna, Moscow region, Russian Federation

autor

Sidorin A. A.

• Joint Institute for Nuclear Research, 6 Joliot Curie Str., 141980 Dubna, Moscow region, Russian Federation

autor

Orlov O. S.

• Joint Institute for Nuclear Research, 6 Joliot Curie Str., 141980 Dubna, Moscow region, Russian Federation

Bibliografia

• 1. Sidorin, A., Meshkov, I., Akhmanova, E., Eseev, M., Kobets, A., Lokhmatov, V., Pavlov, V., Rudakov, A., & Yakovenko, S. (2013). The LEPTA facility for fundamental studies of positronium physics and positron spectroscopy. Mater. Sci. Forum, 733, 291–296. DOI: 10.4028/www.scientific.net/MSF.733.291.
• 2. Murphy, T. J., & Surko, C. M. (1992). Positron trapping in an electrostatic well by inelastic collisions with nitrogen molecules. Phys. Rev. A, 46, 5696–5705. DOI: 10.1103/PhysRevA.46.5696.
• 3. Puska, M. J., & Nieminen, R. M. (1994). Theory of positrons in solids and on solid surfaces. Rev. Mod. Phys., 66, 841–899. DOI: 10.1103/RevMod-Phys.66.841.
• 4. Krause-Rehberg, R., & Leipner, S. H. (1999). Positron annihilation in semiconductors: Defect studies. Berlin: Springer.
• 5. Dryzek, J. (2002). The solution of the time dependent positron diffusion equation valid for pulsed beam experiments. Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms, 196, 186–193. DOI: 10.1016/S0168-583X(02)01253-3.
• 6. Dryzek, J., & Horodek, P. (2008). GEANT4 simulation of slow positron beam implantation profiles. Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms, 266(18), 4000–4009. DOI: 10.1016/j.nimb.2008.06.033.
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• 9. He, C. W., Dawi, K., Platteau, C., Barthe, M. F., Desgardin, P., & Akhmadaliev, S. (2014). Vacancy type defect formation in irradiated α-iron investigated by positron beam Doppler broadening technique. J. Phys. Conf. Ser., 505, 012018. DOI: 10.1088/1742-6596/505/1/012018.
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• 11. Paulin, R., Ripon, R., & Brandt, W. (1974). Diffusion constant and surface states of positrons in metals. Appl. Phys., 4, 343–347. DOI: 10.1007/BF00928390.
• 12. Lukáč, F., Čižek, J., Procházka, I., Jirásková, Y., Janičkovič, D., Anwand, W., & Brauer, G. (2013).Vacancy-induced hardening in Fe-Al alloys. J. Phys. Conf. Ser., 443, 012025. DOI: 10.1088/1742-6596/443/1/012025.