Page 300 - Radiochemistry and nuclear chemistry

284 Radiochemistry and Nuclear Chemistry
FROM THE SUN FROM GALAXIES
Non-isotrop~ padicle flux I~tmpic I~dicle flux
Flux dependent on solar activity Flux independent of solar activity
All masses (mainly 1H, also 3H)) All masses (mainly 1H, no 3H)
Energies < 10 4 GeV Energies 10 4 - 1010 GeV
Minor fraction Major fraction

~
~176
"~
.R~,
oO
~
9 ~149 ~176176176 ~176176176 "~176176176176 ~176176149 o'.~ ~176176176176 ~176149176176176176176176176176176 ~176176176 ~176176 ".~176 ". ~149176
~
"~176
o.
~
~
~176
~
".
"~
o
~
~
Oo
~
9176176149
.
.
.
.
.
~ 12:::2::: . . . . . . . . . . . . . 9 . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . ~ .
~
.
........
i:i-i:i:i:i:i:i:i: ...E~. T.H.'.S .A..T~...SP.HE.R.E !N2.,.O2o,.Ar: et?! AT...A~. ?T " 2.5..KIM...:i:i:i:!:!:i:i:!: .........
o.~ . . . . . . . . . . . . ~ . . . . . . . . . . . . . . . . . . . . . . . . . ~ . . . . o . . . . . . . . . . . . . . ~
:::::: Neutrinos Formation of pions Direct ionization Spallation reactions ":"
............................................................... 9 ."
.
. . . . . . . . . . . . . . . . o . . . ~176176 . . . . . . . . . . . . . .~176 . . . . . . . . . . . . . . . . . . . . . . . . ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.
.
.
.
.
.
.
.
.
~ . . . . . . . 0 ~ 1 7 6 1 7 6 1 . 7. 6. 1 . 7 . 6 . . . . . . . . . . . . . . . . . ~ 1 7 6 . . . . . . . . . . . . . . . . . . . . . .
v ff+ n- ~o e" n p
1Jl t I
v p+ p-
Y
~_. e- I Allen Nuclear reactions
9 belts producing
3H, 2500 m-2 s-1
Hard Soft 10Be, 300 m-2 s-1
component 14C, 22000 m-2 s-1
(50-80%) (-10%) etc
1011 m-2 s-1 2 - 3 ion pairs cm-3 s-1
--- - " ---':"" - --'- ---'-~" Rapidly absorbed -~ 2
"~ Very liffie absorption . --'-=-~ = "----- - . . . . . . . . .
FIG. ]0.1. Cosmic radiation consists of atoms and photons which react with the atmosphere leading to the
formation of numerous secondary particles, some (but not all) detectable at the earth's surface.
and intensities of this radiation have been of great importance to development of models of
the formation and composition of the universe.
The major part of the cosmic radiation is nuclear particles with very high energy:
approximately 70% protons, 20% a-particles, 0.7 % lithium, beryllium, and boron ions,
1.7% carbon, nitrogen, and oxygen ions, the residual 0.6% ions ofZ > 10. These ions are
bare nuclei prior to interaction since their kinetic energies exceed the binding energies of
all of the orbital electrons.
The cosmic particle radiation can be divided by energy into two major groups (Fig. 10.1).
One group has energies mainly below 1 GeV and consists primarily of protons. This group
originates mainly from the sun. Its intensity varies in relation to solar eruptions since at the
time of such an eruption a large amount of solar material, primarily hydrogen, is ejected
into space.
The second group has energies up to 10 l~ GeV, although the intensity of the particles
decreases with increasing energy, following the relation N(E) oc E -1.6 where N(E) is the
number of particles with energies in excess of E. Thus particles of 10 3 GeV have an
intensity of about 101] higher than particles of 10 l~ GeV. Within this high energy group