scholarly journals PLEPS: Pulsed low energy positron system

2015 ◽  
Vol 1 ◽  
Author(s):  
Werner Egger
Keyword(s):  
Positron Annihilation ◽  
Depth Profiling ◽  
Positron Beam ◽  
Low Energy ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Positron Annihilation Lifetime ◽  
Variable Energy

PLEPS, operated by the Universität der Bundeswehr München, located at NEPOMUC, is a unique tool for depth profiling of defects with positron annihilation lifetime spectroscopy using a pulsed positron beam of variable energy.

POSITRON INTERACTION IN POLYMERS

2004 ◽  
Vol 19 (23) ◽  
pp. 3951-3959 ◽  
Author(s):  
CORINE BAS ◽  
N. DOMINIQUE ALBÉROLA ◽  
MARIE-FRANCE BARTHE ◽  
JÉRÉMIE De BAERDEMAEKER ◽  
CHARLES DAUWE
Keyword(s):  
Positron Annihilation ◽  
Chemical Structure ◽  
Positron Beam ◽  
Positron Annihilation Spectroscopy ◽  
Hole Size ◽  
Doppler Broadening ◽  
Positron Source ◽  
Positron Annihilation Lifetime ◽  
Doppler Broadening Spectra ◽  
Variable Energy

A series of dense copolyimide membranes was characterized using positron annihilation spectroscopy. The positron annihilation lifetime spectroscopy performed on film with a classical positron source gives informations on the positronium fraction formed and also on the hole size within the film. The Doppler broadening spectra (DBS) of the gamma annihilation rays coupled with a variable energy positron beam allow the microstructural analyses as a function of the film depth. Experimental data were also linked to the chemical structure of the polyimides. It was found that the presence of the fluorine atoms strongly affects the positron annihilitation process and especially the DBS responses.

scholarly journals A new approach to near-surface positron annihilation analysis of ion irradiated ferritic alloys

2021 ◽  
Author(s):  
Vladimir Krsjak ◽  
Petr Hruška ◽  
Jarmila Degmova ◽  
Stanislav Sojak ◽  
Pavol Noga ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Ion Beam ◽  
Positron Beam ◽  
Ion Beam Irradiation ◽  
Near Surface ◽  
Slow Positron ◽  
New Approach ◽  
Ferritic Alloys ◽  
Positron Annihilation Lifetime ◽  
Variable Energy

The present work provides an innovative approach to the near-surface slow-positron-beam (SPB) study of structural materials exposed to ion-beam irradiation. This approach enables the use of variable-energy positron annihilation lifetime...

Asymmetric Positron Interactions with Chiral Quartz Crystals?

2017 ◽  
Vol 373 ◽  
pp. 221-226 ◽  
Author(s):  
J. David van Horn ◽  
Fei Wu ◽  
Gerald Corsiglia ◽  
Yan Ching Jean
Keyword(s):  
Positron Annihilation ◽  
Depth Profile ◽  
Chiral Recognition ◽  
Shape Parameter ◽  
Positron Beam ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Doppler Broadening ◽  
Quartz Crystals ◽  
Positron Annihilation Lifetime ◽  
The Way

We have studied the interaction of the positron with chiral left-or right-handed quartz crystals. In Doppler-broadening experiments, using a mono-energetic positron beam there is a differential depth profile for positrons implanted in LH or RH z-cut quartz as identified by a shape parameter (S). Further, in bulk positron annihilation lifetime spectroscopy (PALS) experiments, the lifetime (τ 2) attributed to free annihilation of the positron interacting with the chiral lattice exhibits a larger value for the LH quartz, and the associated intensity (I2) is also significantly different—RH quartz is consistently 10% greater than the LH crystal. The τ3 lifetime and its intensity, I3, attributed to positronium interacting with defects in the quartz, also appears to exhibit differences between the enantiomeric sets of crystals. These observations may demonstrate chiral recognition using a positron annihilation technique, pave the way for a broad range of positron experiments, and may help inform hypotheses of chirality recognition, selection, or induction by beta radiation.

A variable energy positron annihilation lifetime spectroscopy study of physical aging in thin glassy polymer films

Polymer ◽  
2009 ◽  
Vol 50 (25) ◽  
pp. 6149-6156 ◽  
Author(s):  
Brandon W. Rowe ◽  
Steven J. Pas ◽  
Anita J. Hill ◽  
Ryoichi Suzuki ◽  
Benny D. Freeman ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Polymer Films ◽  
Physical Aging ◽  
Glassy Polymer ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Spectroscopy Study ◽  
Positron Annihilation Lifetime ◽  
Variable Energy
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