Measurement of low-energy cosmic-ray electron and positron spectra at 1 AU with the AESOP-Lite spectrometer

• Main Authors: Mechbal, Sarah, Mangeard, Pierre-Simon, Clem, John M., Evenson, Paul A., Johnson, Robert P., Lucas, Brian, Roth, James
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: arXiv 2020
• Subjects: High Energy Astrophysical Phenomena astro-ph.HE; Instrumentation and Methods for Astrophysics astro-ph.IM; Solar and Stellar Astrophysics astro-ph.SR; Instrumentation and Detectors physics.ins-det; Space Physics physics.space-ph; FOS Physical sciences; Canada; Ellesmere Island; Esrange
• Online Access: https://dx.doi.org/10.48550/arxiv.2009.03437; https://arxiv.org/abs/2009.03437

We report on a new measurement of the cosmic ray (CR) electron and positron spectra in the energy range of 20 MeV -- 1 GeV. The data were taken during the first flight of the balloon-borne spectrometer AESOP-Lite (Anti Electron Sub Orbital Payload), which was flown from Esrange, Sweden, to Ellesmere Island, Canada, in May 2018. The instrument accumulated over 130 hours of exposure at an average altitude of 3 g.cm$^{-2}$ of residual atmosphere. The experiment uses a gas Cherenkov detector and a magnetic spectrometer, consisting of a permanent dipole magnet and silicon strip detectors (SSDs), to identify particle type and measure the rigidity. Electrons and positrons were detected against a background of protons and atmospheric secondary particles. The primary cosmic ray spectra of electrons and positrons, as well as the re-entrant albedo fluxes, were extracted between 20 MeV -- 1 GeV during a positive solar magnetic polarity epoch. The positron fraction below 100 MeV appears flat, suggesting diffusion dominated solar modulation at low rigidity. The all-electron spectrum is presented and compared with models from a heliospheric numerical transport code. : 21 pages, 13 figures