Detection and energy measurement of electrons above 1 GeV in a multiplate spark chamber

Agrinier, B.; Koechlin, Y.; Parlier, B.; Paul, J.; Vasseur, J.; Boella, G.; Sironi, G.; Russo, Arturo; Scarsi, L.

doi:10.1016/0029-554x(70)90868-2

Cited by 2 publications

(1 citation statement)

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“…For rr° decay alone, this ratio is expected to be 0.12 (Stocker, 1971) consistent with the experimental result. C:rrent estimates of the cosmic ray electron spectra in the high energy region which would produce these gamma rays indicate that the spectral index for the electrons is between 2.5 and 2.8 (Anand et al, 1970;Agrinier et al, 1970;Bleeker et al, 1970;Earl et al, 1970;Fanselow et al, 1969;Marar et al, 1970;Nishimura et al, 1970;and Rockstroh and Webber, 1969). For an electron spectrum with a = 2.6, the ratio R would be 2.03 for bremsstrahlung radiation and 0.74 for Compton or synchrotron radiation.…”

Section: Theoretical Background and Resultsmentioning

confidence: 99%

Gamma-Ray Observations of the Galactic Center and Some Possible Point Sources

Fichtel¹,

Hartman²,

Kniffen³

et al. 1972

ApJ

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A (.5 m by .5 m) digitized spark chamber gamma ray telescope was flown on three balloon flights to look at the galactic center region, Virgo, and the Crab. An excess flux above atmospheric background of over four standard deviations was found for gamma rays exceeding 100 MeV coming from the galactic center region, corresponding to a line intensity of (2.0 +0.6) x 10 -4 y's(cm2 rad see),but there was no statistically significant excess in the 50 to 100 MeV interval, with a 95% confidence limit for the ratio EJ(50 -100 MeV) /J(> 100 McV)]being 0.50. As a result, there is only a 6% chance that Compton or synchrotron radiation from electrons with a power law spectrum having an exponent of 2.6 could make as much as a 50% contribution to the gamma radiation in this energy range. No positive evidence was found for radiation from any of the sources M 87, 3C273, and the Crab Nebula, and 95% confidence upper limits for the gamma ray flux from these objects were set at 1.0 . 10 -5 , 1.0 . 10 -5 , and 6 . 10 -5 /(cm 2 sec) respectively. The M-87 limit eliminates the possibility that the power law spectrum observed at X-ray energies extends unchanged to the high energy gamma ray region.

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