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 104. 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 ~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.
Golden, R., Stochaj, S., Stephens, S., Aversa, F., Barbiellini, G., Boezio, M., et al. (1996). Measurement of the positron to electron ratio in the cosmic rays above 5 GeV RID G-6769-2011. THE ASTROPHYSICAL JOURNAL LETTERS, 457(2), L103-L106 [10.1086/309896].
Measurement of the positron to electron ratio in the cosmic rays above 5 GeV RID G-6769-2011
RICCI, MARCO;PICOZZA, PIERGIORGIO;SPARVOLI, ROBERTA;
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 104. 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 ~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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.