Measurement of the orthopositronium confinement energy in mesoporous thin films

Journal Article · Sat May 15 00:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.81.052703· OSTI ID:21408830

Crivelli, Paolo; Gendotti, Ulisse; Rubbia, Andre; Liszkay, Laszlo; Perez, Patrice; Corbel, Catherine ^[1]

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1. Instituto de Fisica, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, 21941-972 (Brazil)

In this paper, we present measurements of the ortho-positronium (ortho-Ps) emission energy in vacuum from mesoporous films using the time-of-flight technique. We show evidence of quantum mechanical confinement in the mesopores that defines the minimal energy of the emitted Ps. Two samples with different effective pore sizes, measured with positron annihilation lifetime spectroscopy, are compared for the data collected in the temperature range 50-400 K. The sample with smaller pore size exhibits a higher minimal energy (73{+-}5 meV), compared to the sample with bigger pores (48{+-}5 meV), due to the stronger confinement. The dependence of the emission energy with the temperature of the target is modeled as ortho-Ps being confined in rectangular boxes in thermodynamic equilibrium with the sample. We also measured that the yield of positronium emitted in vacuum is not affected by the temperature of the target.

• OSTI ID: 21408830
• Journal Information: Physical Review. A, Vol. 81, Issue 5; Other Information: DOI: 10.1103/PhysRevA.81.052703; (c) 2010 The American Physical Society; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ANNIHILATION
CONFINEMENT
EMISSION
EQUILIBRIUM
LIFETIME
MEV RANGE
NANOSTRUCTURES
POSITRONIUM
POSITRONS
QUANTUM MECHANICS
SPECTROSCOPY
TEMPERATURE RANGE
THIN FILMS
TIME-OF-FLIGHT METHOD
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
FILMS
INTERACTIONS
LEPTONS
MATTER
MECHANICS
PARTICLE INTERACTIONS