The analysis presented in this section refers to Galactic Cosmic Rays recorded by NINA in the solar quiet
period December 1998-March 1999.
To select a sample of pure low energy (E > 10 MeV/n) primary cosmic rays, and avoid the distortions induced
by the Earth magnetic field, only particles registered at a value of L-shell > 6 (L geomagnetic
shell) have been chosen.
Figure 1 presents the relative abundances for
galactic heavy particles (normalised to O) as detected by
NINA. This is a sample of pure GCR's, because the filter
applied to the data (number of silicon layers crossed > 6) excluded the less energetic SCR and
ACR nuclei. The counting rates of Figure 1 reproduce the existing cosmic ray abundances,
with the odd-even effect, the peaks at carbon and oxygen, and the
relative depression of the light elements Li, Be and B.
In Figure 2 NINA flux of galactic 4He is plotted together with the results from the mission SIS on ACE, about in the same period of observation. Data from SIS on ACE belong to a cycle of 27 days from 1999 February 6 to 1999 March 4, and are the sum of 3He and 4He. There is a general agreement among the two sets of results. However there are differences between the results of NINA and SIS, which can be attributed to the different time period (since the flux of helium is known to change significantly over the months) and to the fact that the SIS flux include also 3He.
In Figures 3 and 4 the NINA differential energy spectra of galactic 12C and 16O are plotted together with results from the missions SIS and CRIS on ACE, both referred to the period 1999 February 6 to 1999 March 4. The fluxes measured on board NINA are in very good agreement with those on ACE.
Figure 5 shows the detection of Z > 4 particles over the polar regions. Iron was recorded too.