Differential Energy Spectra of Low-Energy (<8.5 MeV per Nucleon) Heavy Cosmic Rays during Solar Quiet Times

Carbon, oxygen, and heavier nuclei have been observed below 8 MeV per nucleon during solar quiet times. We find that the C/O abundance ratio is 0.8±0.4, the N/O ratio is 0.4±0.25, and the differential energy spectra below 1 MeV per nucleon have the form $K{E}^{-4.9\mathrm{}\pm 0.3}$. We infer from this spectral form that most of these particles are likely to be of solar origin. The large errors on the abundance ratio do not allow a decisive answer to the likely origin.