On-ground detection of an electron-positron annihilation line from thunderclouds.
Phys Rev E
; 93(2): 021201, 2016 Feb.
Article
em En
| MEDLINE
| ID: mdl-26986281
ABSTRACT
Thunderclouds can produce bremsstrahlung gamma-ray emission, and sometimes even positrons. At 002700 (UT) on 13 January 2012, an intense burst of gamma rays from a thundercloud was detected by the GROWTH experiment, located in Japan, facing the Sea of Japan. The event started with a sharp gamma-ray flash with a duration of <300 ms coincident with an intracloud discharge, followed by a decaying longer gamma-ray emission lasting for â¼60 s. The spectrum of this prolonged emission reached â¼10 MeV, and contained a distinct line emission at 508±3(stat.)±5(sys.) keV, to be identified with an electron-positron annihilation line. The line was narrow within the instrumental energy resolution (â¼80keV), and contained 520±50 photons which amounted to â¼10% of the total signal photons of 5340±190 detected over 0.1-10 MeV. As a result, the line equivalent width reached 280±40 keV, which implies a nontrivial result. The result suggests that a downward positron beam produced both the continuum and the line photons.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Diagnostic_studies
Idioma:
En
Revista:
Phys Rev E
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Japão