As part of a series of experiments to search for antimatter in cosmic rays, the New Mexico State University balloon-borne magnet spectrometer was configured for a flight to study positrons. Two completely new instruments, a transition radiation detector and a silicon-tungsten imaging calorimeter, were added to the magnet spectrometer. These two detectors provided a proton rejection factor better than 3 x 10(4). This instrument was flown from Fort Sumner, New Mexico, at an average depth of 4.5 g cm(-2) of residual atmosphere for a period of 25 hr. We report here the measured fraction of positrons e(+)/(e(+) + e(-)) from similar to 5 to 60 GeV at the top of the atmosphere. Our measurements do not show any compelling evidence for an increase in this ratio with energy, and our results are consistent with a constant fraction of 0.078 +/- 0.016 over the entire energy region.

Measurement of the positron to electron ratio in the cosmic rays above 5 GeV

VACCHI, Andrea
1996-01-01

Abstract

As part of a series of experiments to search for antimatter in cosmic rays, the New Mexico State University balloon-borne magnet spectrometer was configured for a flight to study positrons. Two completely new instruments, a transition radiation detector and a silicon-tungsten imaging calorimeter, were added to the magnet spectrometer. These two detectors provided a proton rejection factor better than 3 x 10(4). This instrument was flown from Fort Sumner, New Mexico, at an average depth of 4.5 g cm(-2) of residual atmosphere for a period of 25 hr. We report here the measured fraction of positrons e(+)/(e(+) + e(-)) from similar to 5 to 60 GeV at the top of the atmosphere. Our measurements do not show any compelling evidence for an increase in this ratio with energy, and our results are consistent with a constant fraction of 0.078 +/- 0.016 over the entire energy region.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11390/1125197
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