In situ cosmogenic seminar

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In situ cosmogenic seminar
3. ?????
Outline 1. ???(?????????) 2. ????????(?????)
?? ?? matsushi_at_n.t.u-tokyo.ac.jp
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1. ???????????
1. ???(?????????)
Goal ????????????????.
Outline 1. ??????????? 2. Stone (2000)??????? 3.
???????
3
1. ???????????
P (l, z)
4
Dipole field?????cut off
???????????????? ??????(cutoff risidity)R?,
S
N
p ??????(GeV/c) c ???(m/s) q ??(e) M
??????????(Wb) R ?????(m) l ?????()
5
???????????(??????????)
???????????????? (Lal and Peters, 1967????)
0 g/cm2
??????????, ??(??)?3???
60
40
20
0
Depth of atmosphere
???????1?? ????????. ? ??????????.
Lat. gt 80
1030 g/cm2
Cosmic ray flax (log scale)
PAl/PBe 6.0
Nishiizumi et al. (1989) Sierra Nevada
?????? ?????10Be, 26Al???
PBe 61.9 3.0 atoms/g/yr PAl
373.627.8 atoms/g/yr
l 44(38in Geograph. lat.) z 20003500 m
(670800 g/cm2) 11,000 yr exposure (from 14C
dating).
PBe 6.1 atoms/g/yr at SLHL PAl 36.8
atoms/g/yr at SLHL
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Lal (1991) ???P ?????l ?????????? z ?3???
Dunai (2000) ???????????? non-dipole ?????.
Nishiizumi et al., 1989
Stone (2000) ???????????, ???????.
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2. Stone (2000)???????
??????????????. ?????????????
1. ???(?????????)
Goal ??????????????
Outline 1. ??????????? 2. Stone (2000)??????? 3.
???????
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2. Stone (2000)???????
??????????????. ?????????????
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2. Stone (2000)???????
??????????????. ?????????????
Stone, 2000. JGR 105, 2375323759.
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2. Stone (2000)???????
??????????????. ?????????????
Stone, 2000. JGR 105, 2375323759.
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PBe at SLHL 5.1 0.3 atoms/g/yr PAl at SLHL
31.1 1.9 atoms/g/yr
???????????
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PBe at SLHL 5.1 0.3 atoms/g/yr PAl at SLHL
31.1 1.9 atoms/g/yr
???????????
fsp 0.974 (for 10Be), 0.978 (for 26Al).
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PBe at SLHL 5.1 0.3 atoms/g/yr PAl at SLHL
31.1 1.9 atoms/g/yr
???????????
fsp 0.974 (for 10Be), 0.978 (for 26Al).
???????????????????. ??????,??????????.
14
??????????
????????,??? ?????????????.
200
150
100
50
Production rate (atoms/g/yr)
Altitude (km)
Latitude (degree N)
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3. ???????
????????????? ????????
1. ???(?????????)
Goal ????????????????.
Outline 1. ??????????? 2. Stone (2000)??????? 3.
???????
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3. ???????
????????????? ????????
Cosmic ray flux
Depth
log-log scale
10Be, 26Al?????,3??????????,
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3. ???????
????????????? ????????
Cosmic ray flux
Depth
log-log scale
10Be, 26Al?????,3??????????,
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????????
Production rate (atoms/g/yr)
100
101
10-2
10-3
10-4
10-1
101
Neutron
Slow m
102
Spallation
Fast m
Total
Depth (g/cm2)
103
Muon induced reactions
104
105
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???
???????????,????????????.
?Stone (2000)?????????,??????????????.
?????????,???????????????.
????????,5 m ?????????????????.