Secondary cosmic rays in the NUCLEON space experiment

Abstract

The NUCLEON space observatory is a direct cosmic ray spectrometer designed to study cosmic ray nuclei with Z = 1−30 at energies 10 12 −10 15 eV. It was launched as an additional payload onboard the Russian Resource-P No. 2 satellite. In this work B/C, N/O and subFe/Fe ratios are presented. The experiment has worked for half of its expected time, so the data have preliminary status, but they already give clear indications of several astrophysical phenomena, which are briefly discussed in this paper.

Measurement of the cosmic-ray secondary-to-primary ratios with CALET on the International Space Station

“…Our result is well consistent with PAMELA, but lower than AMS-02 like the cases of carbon, oxygen and iron spectra [7,15]. Figure 9 shows the preliminary result of B/C ratio as a function of kinetic energy per nucleon from 16 GeV/ to 2.2 TeV/ compared with the previous observations [29][30][31][32][33][34][35]. Our result is well consistent with previous measurements such as CREAM-I, PAMELA and AMS-02.…”

Cosmic ray models

“…is expected at the energy when the average path length of electrons becomes comparable to the height H of the CR halo. A second break with a steepening to F (E) ∝ E −(α+1) should occur, Figure 13: Boron-to-carbon ratio as function of kinetic energy per nucleon measured by the CREAM [199], AMS-02 [127], and NUCLEON [200] experiments. The power law predicted by Kolmogorov turbulence (1/E 1/3 ) and Iroshnikov-Kraichnan turbulence (1/E 1/2 ) at high energies are also shown.…”

“…In Fig. 13, we show the B/C ratio as function of the kinetic energy per nucleon measured by the AMS-02 [127], CREAM [199] and NUCLEON [200] experiments. One can see that the data are consistent with the slope δ = 1/3 predicted by Kolmogorov turbulence, while the decrease of the B/C ratio predicted by Iroshnikov-Kraichnan turbulence is too strong.…”

Advances in direct measurements of cosmic rays

“…(See Ref. 63 for details.) The index δ ranges from 0.3 to 0.7, depending on the model, as illustrated in Fig.…”

“…The scale height of the CR halo constrained by the 10 Be/ 9 Be ratio is about 4-10 kpc, Fig. 7 B/C ratio data: purple filled X's, HEAO-3 [22]; grey open crosses, CRN [23]; pink open diamonds, ATIC-2 [62], brown filled circles, CREAM-I [59]; orange open triangles, TRACER [38]; black filled diamonds, NUCLEON [63]; red filled stars, AMS-01 [47]; and small blue circles, AMS-02 [60]. The curves represent a propagation model with a power law diffusion coefficient ∝ R δ with δ = 0.333, grey dash-dot line; δ = 0.6, green dashed line; and δ = 0.7, purple dotted line.…”