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Positron lifetime spectrometers: PALS

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Contact details

Schut, Henk Dr.
Applied Sciences (TNW), Section NPM2 (Neutron and Positron Methods in Materials)
Mekelweg 15, 2629 JB Delft
Tel : +31 (0)15 27 81961
E-mail : h.schut@tudelft.nl
Website : Open website

General Information

Instrument:

Positron lifetime spectrometers: PALS

Location:

Experimental hall, Reactor Institute Delft, Mekelweg 15, Delft (building #50)

Key words:

positron lifetime, voids, free volume

Measured quantity:

one measures the annihiliation (gamma) radiation of a positron-electron annihilation event (511 keV)

Main application:

Characterization of open volume defects (size and concentration) and free volume (aging) in polymers by measuring the lifetime of positrons and positronium.

Instrument specification

(two) positron lifetime spectrometers

Positron source:
22Na isotope (1 MBq) sandwiched between 7 micron thick kapton foils

Digital pulse processing.

Detectors:
two sets of scintillation detectors, time resolution of about 200 ps

Other contact
Dr. S.W.H. Eijt
Section FAME (Fundamental Aspects of Materials and Energy)
Department R3 (Radiation, Radionuclides and Reactors)
Faculty of Applied Sciences
Mekelweg 15
2629 JB Delft, The Netherlands
tel: +31 (0)15 27 89053
E-mail: S.W.H.Eijt@iri.tudelft.nl

Positron facilities and positron research activities at RID and R3
The Positron Centre Delft is a research facility established at the Delft University of Technology. It provides access to the equipment (as part of RID) and scientific expertise concentrated in the sections FAME and NPM2 of the department R3 of the faculty of Applied Science.
The majority of the experimental Positron Annihilation (PA) techniques developed to this aim are based on the analysis of the annihilation radiation. They can be classified into two groups, which are distinguished by the positron’s sensitivity to the local electron density (positron lifetime, PALS) and to the local electron momentum distribution (Dopplerbroadening (PADB) and Angular Correlation (2D-ACAR)).