Positronium reemission yield from mesostructured silica films

Liszkay Laszlo (1) , Catherine Corbel (2) , Patrice Perez (3) , Pierre Desgardin (4) , M.-F. Barthe (4) , Toshiyuki Ohdaira (5) , Ryoichi Suzuki (5) , Paolo Crivelli (6) , Ulisse Gendotti (6) , André Rubbia (6) , Matieu Etienne (7) , Alain Walcarius (7)

1 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
2 LSI - Laboratoire des Solides Irradiés - Irradiated Solids Laboratory
3 DPhP - Département de Physique des Particules (ex SPP)
4 CERI - Centre d'Études et de Recherches par Irradiation
5 AIST - National Institute of Advanced Industrial Science and Technology
6 Institut für Teilchenphysik
7 LCPME - Laboratoire de Chimie Physique et Microbiologie pour l'Environnement

The reemission yield of ortho-positronium (o-Ps) into vacuum outside mesoporous silica films on glass is measured in reflection mode with a specially designed lifetime (LT) spectrometer. Values as high as 40% are found. The intensity of the 142 ns vacuum LT is recorded as a function of reemission depth. The LT depth profiling is correlated to the 2gamma and 3gamma energy ones to determine the annihilation characteristics inside the films. Positron lifetime in capped films is used to determine the pore size. For the first time, a set of consistent fingerprints for Ps annihilation, o-Ps reemission into vacuum, and pore size, is directly determined in CTACl-TEOS films.

Mots clés: positron annihilation; positronium emission; nanoporous silica; mesoporous silica

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Autre [cond-mat.other]

Liszkay Laszlo, Catherine Corbel, Patrice Perez, Pierre Desgardin, M.-F. Barthe, et al.. Positronium reemission yield from mesostructured silica films. 2007. ⟨hal-00201089v3⟩