Observation of Low-Energy Positron Diffraction Patterns with a Linac-Based Slow-Positron Beam

A simple pulsed slow positron beam based on a Penning-trap has been designed and is being constructed in Wuhan University. The cooled positrons from the trap with very low energy dispersion are dumped and chopped to pulses of a few tens of ns in width. Positron pulses are bunched by adjusting the potential of drift tube using an arbitrary wave generator, then accelerated to the target. Influences of the pulse width, the energy dispersion of positrons etc. on the time resolution of bunched positron pulse are simulated. The result shows that lower energy dispersion of positrons leads to much narrower positron pulses, indicating that a trap-based slow positron beam has a great advantage in developing a pulsed slow positron beam.

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Polymer Nanocomposites with Silver Nanoparticles Formed by Low-Energy Ion Implantation: Slow Positron Beam Spectroscopy Studies

NATO Science for Peace and Security Series A: Chemistry and Biology - Nanostructured Materials for the Detection of CBRN ◽

10.1007/978-94-024-1304-5_21 ◽

2018 ◽

pp. 293-300 ◽

Cited By ~ 2

Author(s):

T. S. Kavetskyy ◽

M. O. Liedke ◽

N. Srinivasan ◽

A. Wagner ◽

R. Krause-Rehberg ◽

...

Keyword(s):

Silver Nanoparticles ◽

Ion Implantation ◽

Polymer Nanocomposites ◽

Positron Beam ◽

Low Energy ◽

Slow Positron ◽

Spectroscopy Studies

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Slow positron beam at the JINR, Dubna

Nukleonika ◽

10.1515/nuka-2015-0130 ◽

2015 ◽

Vol 60 (4) ◽

pp. 725-728 ◽

Cited By ~ 10

Author(s):

Paweł Horodek ◽

Andrey G. Kobets ◽

Igor N. Meshkov ◽

Alexey A. Sidorin ◽

Oleg S. Orlov

Keyword(s):

Diffusion Length ◽

Nuclear Research ◽

Positron Beam ◽

Positron Annihilation Spectroscopy ◽

Low Energy ◽

Positron Energy ◽

Slow Positron ◽

Tungsten Foil ◽

Sample Chamber ◽

Variable Energy

Abstract 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.

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Proposal of a high-field superconducting wiggler for a slow positron source at SPring-8

Journal of Synchrotron Radiation ◽

10.1107/s0909049597018773 ◽

1998 ◽

Vol 5 (3) ◽

pp. 360-362 ◽

Cited By ~ 9

Author(s):

A. Ando ◽

S. Daté ◽

M. G. Fedurin ◽

M. Hara ◽

H. Kamitsubo ◽

...

Keyword(s):

High Field ◽

Magnetic System ◽

Positron Beam ◽

Beam Current ◽

High Energy ◽

Low Energy ◽

Positron Source ◽

Slow Positron ◽

Unique Probe ◽

Suitable Target

A low-energy positron beam is a unique probe of materials. In high-energy electron and positron storage rings it is possible to generate intense synchrotron radiation with a photon energy of 1–3 MeV by installing a high-field (8–10 T) superconducting wiggler. High-energy photons are converted to low-energy positrons by using a suitable target–moderator system. For an 8 GeV electron storage ring at a beam current of 100 mA, final yields are estimated to be about 108–1010 slow-e+ s−1 or larger depending on the moderation efficiency, with the size of the positron source 101–102 cm2. In the present work a wiggler magnetic system of 10 T is proposed. The main parameters of the superconducting wiggler are presented.

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Positron Annihilation Spectroscopy at LEPTA Facility

Materials Science Forum ◽

10.4028/www.scientific.net/msf.733.322 ◽

2012 ◽

Vol 733 ◽

pp. 322-325 ◽

Cited By ~ 4

Author(s):

Aleksey A. Sidorin ◽

Igor Meshkov ◽

E. Ahmanova ◽

M. Eseev ◽

A. Kobets ◽

...

Keyword(s):

Positron Annihilation ◽

Condensed Matter ◽

Positron Beam ◽

Positron Annihilation Spectroscopy ◽

Layered Structures ◽

Low Energy ◽

Slow Positron ◽

Monochromatic Beam

The Low Energy Positron Toroidal Accumulator (LEPTA) at JINR proposed for generation of positronium in flight can be used for positron annihilation spectroscopy (PAS) [1]. The positron injector of the LEPTA facility can generate continuous a slow positron beam with the intensity up to 1∙107s-1 at the energy in the range of a few eV to 100 keV and width of the spectrum 1 – 2 eV. The injector is based on radioactive 22Na isotope. The solid neon is used as a moderator to generate monochromatic beam. The parameters of the positron beam allow scanning the condensed matter in depth up to 10 microns with resolutions less than 10 nanometers and investigating layered structures for microelectronics and properties of a surface.

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