Relative abundance of elements at Earth cosmic rays - solar system ~ 1 GeV/n Si = 100 JRH, Adv. Space Res. 41 (2008) 442
TRACER Energy Spectra for individual elements D. Müller et al., ICRC 2007
Energy spectra of main elements in cosmic rays
SNR acceleration: Sveshnikova ++ 2003 Diffusion: Kalmykov+JRH 2007 poly gonato ~Z JRH, Adv. Space Res. 41 (2008) 442
SNR acceleration: Sveshnikova ++ 2003 Diffusion: Kalmykov+JRH 2007 poly gonato ~Z JRH, Adv. Space Res. 41 (2008) 442
Transport equation for cosmic rays in the diffusion Galaxy energy loss (Bethe Bloch) loss through interactions! with ISM (spallation) loss through radioactive decay N i t = (D i N i ) E (b in i ) nνσ i N i N i γτ i + Q i + j>i nνσ ij N j + j>i N j γ j τ ij source term production through spallation! of heavy neulcei production through decay! of heavy nuclei
Age of galactic cosmic rays Residence time in Galaxy 10Be 10B + e- (τ=2.4 106 a) 10Be 10B e- τ = 17*106 a
Relative abundan 10-1 10-2 Pathlength of cosmic rays 10-3 10-4 10-5 10-6 0 10 20 30 40 50 Nuclear charge num Fig. 3. Abundance of elements in cosmic rays as function of their nuclear charge num Abundance for nuclei with Z 6 28 according to Simpson (1983). Heavy nuclei as measured 3 (Binns et al., 1989), SKYLAB (Shirk and Price, 1978), TIGER (Lawrence et al., 1999), T g/cm2of elements in the as well as UHCRE (Donelly et al., 1999). In addition, the abundance C B+n+p λ(e) E 0.6 0.4 experime 0.15 g/cm =10 g/cm2 0.35 The sp B/C 0.3 tion influ assumed 0.25 same slo 0.2 ing the e and the 0.15 2 =5 g/cmaccount, 0.1 nuclei sh (Ho rand (Sc+V)/Fe 0.05 for iron n 0 sponding 102 103 104 105 indicate Energy [MeV/n] compare N. Yanasak, ApJ 563 (2001) 768 ues for Fig. 4. Abundance ratio of boron to carbon and scandium + vanadium to Relative abundance spallation primary/secondary-ratio HEAO-3 ACE/CRIS
TRACER - Mc Murdo, Antarctica, 2003
charge Transition Radiation Array for Cosmic Energetic Rays de/dx trajectory energy TR trajectory energy suppress low energy particles Geometric factor: 5 m 2 sr 1600 proportional tubes total
Transition Radiation Array for Cosmic Energetic Radiation Ft. Sumner, New Mexico 1 day 1999 McMurdo, Antarctica 10 days 2003 8 Z 26 Kiruna, Sweden 4 ½ days 2006 4 Z 26 Responses in arb.units Direct measurement of the composition of cosmic rays from 0.5 to 10,000 GeV/amu with single elemental resolution Combined responses for energy measurements over 4 decades: Cherenkov: 0.5 10 GeV/amu (n=1.49) Specific Ionization in gas: 10 1000 GeV/amu TRD: 400 several 10,000 GeV/ amu Lorentz factor γ L ~ (1 1/n 2 β 2 ) de/dx ~ 1/β 2 ln (E) TR = de/dx + x-rays all signals scale with Z 2 5m 2 sr - currently the largest cosmic-ray detector on balloons
TRACER - Mc Murdo, Antarctica, 2003 A. Romeo J.R. Hörandel P. Boyle G. Kelderhouse D. Müller D. Pernik M. Ave-Pernas
Cosmic-ray propagation B/C ratio 7.2. Discussion of the Result 77 path length B/C ratio -1 10 TRACER HEAO CRN ATIC CREAM AMS-01 ] 2 escape pathlength! esc [g/cm 10 1 Leaky-Box Fit GALPROP -0.6 "! E -2 10-1 2 3 10 1 10 10 10 10 kinetic Energy [GeV/amu] Figure 3: The boron-to-carbon abundance ratio as a function of kinetic energy per nucleon. Error bars are statistical (thin) and systematic (thick). Previous measurements are shown from HEAO [6], CRN [11], ATIC [9], CREAM [2] A. Obermeier et al., ICRC (2011) 4-1 10 1 10 2 10 10 10 kinetic energy [GeV/amu] Figure 7.4: The escape pathlength Λ esc as derived from the TRACER measurement with δ =0.53 ± 0.06 and Λ 0 =0.31± 0.55 0.31 g/cm2. The escape pathlength is defined in Eq. 7.9. The dashed lines illustrate the 1σ uncertainty range for the escape pathlength. A. Obermeier, PhD thesis, RU Nijmegen (2011) Using the same power-law index that fits the low-energy data, δ =0.6, avalueforthe 3 4