Positron Annihilation Spectroscopy at LEPTA Facility

Sidorin, A. O.; Мешков, И. Н.; Ahmanova, Ekaterina; Есеев, М. К.; Kobets, A. G.; Lokhmatov, V. I.; Павлов, В. Н.; Rudakov, A. Yu.; Yakovenko, S. L.

doi:10.4028/www.scientific.net/msf.733.322

Cited by 5 publications

(4 citation statements)

References 1 publication

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“…In this paper we present results obtained from slow positron beam working at LEPTA facility [18,19] at Joint Institute for Nuclear Research in Dubna, Russia. Nowadays, positron beams offer the possibility to detect changes closer to surface in comparison to classic measurements based on positrons emitted directly from a radioactive source [20].…”

Section: Pas Techniquementioning

confidence: 96%

Positron beam and RBS studies of thermally grown oxide films on stainless steel grade 304

Horodek

Siemek

Kobets

et al. 2015

Applied Surface Science

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Section: Pas Techniquementioning

confidence: 96%

Positron beam and RBS studies of thermally grown oxide films on stainless steel grade 304

Horodek

Siemek

Kobets

et al. 2015

Applied Surface Science

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“…The slow monochromatic positron flux is formed from broad spectrum of positrons from radioactive isotope 22 Na. The positrons with energy up to 0.54 MeV are moderated to the energy of few eV in the solid neon [2]. Maximum flux of slow positrons determined by standard method for coincidence scheme was equal: N max ≈ 1.5⋅10 5 positrons/ sec.…”

Section: Test Of the New Positron Sourcementioning

confidence: 91%

“…The LEPTA facility is a small positron storage ring equipped with the electron cooling system and positron injector. The maximum positron energy is of 10 keV [2]. The storage ring is aimed for generation of direct fluxes of orthopositronium (o-Ps), produced in recombination of the positron beam circulating in the ring with single pass cooling electron beam.…”

mentioning

confidence: 99%

The LEPTA Facility for Fundamental Studies of Positronium Physics and Positron Spectroscopy

Sidorin

Мешков

Ahmanova

et al. 2012

MSF

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At present time the Low Energy Positron Toroidal Accumulator (LEPTA) at JINR is under commissioning with circulating positron beam. The LEPTA facility is a small positron storage ring equipped with the electron cooling system and positron injector. The maximum positron energy is of 10 keV. The storage ring is aimed for generation of direct fluxes of ortho-positronium (o-Ps), produced in recombination of the positron beam circulating in the ring with single pass cooling electron beam. The project has few goals: annihilation spectroscopy (PAS) to monitoring defects of nanometer sizes in materials as a function of depth managed by the positron energy in a rage of a few eV to 100 keV.

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“…The width of the positron spectrum is about 2 eV. This flux can be used for fundamental and applied research [2]. It is possible to carry out layer-by-layer scanning of the defects in subsurface layers of the samples at depths from zero to several micrometers by varying the positron energy in the range of 0.05÷35 Kev.…”

mentioning

confidence: 99%

Positron annihilation spectroscopy on a beam of positrons the LEPTA facility

et al. 2016

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Abstract.The results and possibilities of the samples surfaces research by the Doppler method of positron annihilation spectroscopy (PAS) for a monochromatic beam of positrons at the LEPTA facility are presented in this paper. Method with high-resolution sensitivity to defects like vacancies and dislocations allows scanning of the surface and near-surface sample layers to a depth of several micrometers by the method of Doppler broadening of annihilation lines. The opportunities for the development of a PAS method based on the measurement of the positron lifetime in the sample irradiated by ordered flow of positrons from the injector of accelerator complex LEPTA at JINR are discussed.LEPTA facility [1] is a complex consisting of the cryogenic positron source based on the emitter -a radioactive 22Na with an activity of 30 mCi, the electromagnetic PenningMalmberg-Surko trap (PMS) and storage ring. After slowing down in a frozen solid neon layer a monochromatic flux of positrons with intensity up to 10 6 part./sec is formed. The width of the positron spectrum is about 2 eV. This flux can be used for fundamental and applied research [2]. It is possible to carry out layer-by-layer scanning of the defects in subsurface layers of the samples at depths from zero to several micrometers by varying the positron energy in the range of 0.05÷35 Kev. For this purpose, one of three versions of the PAS can be used [3]: observation of correlations in the angular distribution of annihilating photons -gamma quanta (ADAP), measurement of the lifetime of positrons in matter with registration the time distribution of the annihilation photons (TDAP) and the change in energy of the annihilation gamma-quanta -registration of Doppler broadening of annihilation lines (DBAL).The most perspective methods that allow to distinguish the defects of vacancy and dislocation types in samples with a sensitivity of 1 defect per 10 7 atoms in the crystal lattice and at depth resolution of the sample in tenths of nanometer, are the last two versions -TDAP and DBAL. Currently, at the LEPTA complex DBAL PAS method is used with the * Corresponding author: m.eseev@narfu.ru

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Positron Annihilation Spectroscopy at LEPTA Facility

Cited by 5 publications

References 1 publication

Positron beam and RBS studies of thermally grown oxide films on stainless steel grade 304

Positron beam and RBS studies of thermally grown oxide films on stainless steel grade 304

The LEPTA Facility for Fundamental Studies of Positronium Physics and Positron Spectroscopy

Positron annihilation spectroscopy on a beam of positrons the LEPTA facility

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