ar X iv : q ua nt - p h / 03 03 16 6 v 1 2 7 M ar 2 00 3 Orthopositronium : ’ Annihilation of positron in gaseous neon ’

On the basis of phenomenological model of the orthopositronium annihilation ‘isotope anomaly’ in gaseous neon (lifetime spectra, positrons source Na) the realistic estimation of an additinal mode (∼ 0.2%) of the orthopositronium annihilation is received. PACS: 36.10.Dr, 13.90.+i, 06.09.+v In huge volume of the data on lifetime spectra of annihilation in substance of positrons from β-decay Na Na(3) → Ne(2) + e+β + ν, received for half a century of making of these measurements, the experimental situation for gaseous neon proved to be unique [1,2]. In a method of delayed γn-γa-coincidences (‘lifetime method’) the appearance of positron in substance is registered by nuclear γn-quantum (‘start’) Ne(2) τ∗∼ 5.24ps −−−−−−−→ Ne(0) + γn(∼ 1.27 MeV), and its annihilation – on one of γa-quanta (‘stop’) as a result of annihilation e+β + e −(in substance) → most probably annihilation on 2 or 3 γa-quanta. The counter, developing signal ‘stop’, registers not only γa-quantum (with energy ≤0.5 MeV) but also γn-quantum (∼1.27 MeV) with recording efficiency