平成 20 年度課題研究 P4 レポート
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Transcript of 平成 20 年度課題研究 P4 レポート
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20 P4
2009 3 31
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1 2
1.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 . . . . . . . . . . . . . 5
2 5
2.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.5 Cd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3 21
3.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.3 RPMT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4 35
4.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
1
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Abstract
P4
S/N
()
S/N
1
1.1
1. ()2.
3.
2
13
1.2
1.
2. ()
3.
4.
1.2.1
LiF
p +7Li n +7Be (1)
C
3.0MeV 200nA
1.2.2
1 n
i(i = 1, 2, ) Ni i
2
-
1
= N11 + N22 + Nnn (2)
1 k
NkkN11 + N22 + Nnn
(3)
P (lab)n P(lab)p
MnMp
P (cm)n = P(lab)n
MnMn + Mp
(P (lab)n + P(lab)p ) (4)
1
1 (, )
P (cm)n =
P(cm)nx
P(cm)ny
P(cm)nz
= |P (cm)n |sincossinsin
cos
(5) 1
P (lab)n P (lab)n
1.2.3
Mnd2rdt2
= (n B) (6)
z 10mm B = C2 (x2 +y2), C =
23500[T/m2] L0
3
-
2
L1L2 3.3.1
(6) x
x = 2x (7)
2 = nC/Mn z = 0
z = L1 + L2 x
x(+) = {x0+(L0+L2)vx0/vz0}cosh(L1/vz0)+{x0L2/vz0+vx0(1/+L0L2/v2z0)}sinh(L1/vz0), (8)
x() = {x0 +(L0 +L2)vx0/vz0}cos(L1/vz0)+{x0L2/vz0 +vx0(1/L0L2/v2z0)}sin(L1/vz0) (9)
y x y 0x,y,z
vz0 0
x(+) = x0cosh(L1/vz0) + (x0L2/vz0)sinh(L1/vz0), (10)
x() = x0cos(L1/vz0) (x0L2/vz0)sin(L1/vz0) (11)
x0 = 5[mm] = 378[1/s]L1 = 300[mm]L2 = 2800[mm]
1 ( n [7])
x(+) x()
1.3
2 (kB Boltzmann)
4
-
1
vz0[m/s] x(+)[mm] x()[mm]
2500 5.10 4.90
2000 5.16 4.84
1500 5.28 4.72
2
T = 300[K]
kBT ' 1/40[eV] 2200[m/s]
1.8
1.4
u 1 d 2 1/2
Dirac x = zxeh/2mx,
zd = 1/3, zu = 2/3
0 ()
|>= {a|> |> |>+b|> |> |>+c|> |> |>} {p|u> |d> |d>+q|d> |u> |d>+r|d> |d> |u>}
(12)
1/2
|>= 118
{2(|ud d>+|dud>+|ddu>) |udd>|dud>
|udd>|ddu>|dud>|ddu>}(13)
n ==43d
13u (14)
1/3 313MeV*1 N
n = 2.0N (15)
[7] 2 1.9N
2
2.1
2.1.1
RI
0.025eV15MeV Sv/h
*1
5
-
2.1.2
3He
2
3He
2.2.3
0.025eV15MeV (ICRP)
2.2
2.2.1
Gas Ionization Detector 3 [3, P128,Fig. 6.1.]
3
Gas Ionaizaton Detector
ionization chamberproportional counterGeiger-Muller counter
4 [3, P128,Fig. 6.2.]
II (Ionization chamber) ()
III(proportional chamber)
proportional chamber
IIIIV(limited proportionality)
6
-
4
IV -
Poisson
E =V0
r ln (b/a)(16)
a:
b:
r:
7
-
2.2.2
good proportionalityhigh rate capability
3He BF3
higher specific ionization
(11.6eV) 103104 (CO2
BF3 )
106 Ar90% 10% (P10 )
(CF3Br)
107
2.2.3
1 3atm3He 3He
5 3He
3He + n t + p + 765keV (17)
6 t
3He
8
-
6
JENDL [1] 3He (1/40eV 5333bn)102105 1/v E eV (E)bn
(E) =5333
40E
12 (18)
P (E) =1a
a0
1 exp{NA n (E) 2
a2 y2}dy (19)
7
a = 1.27[cm]:
NA:
n: 3He mol
R:
300K
8 ( pulse height count)
32ch
pulse height 32ch
9
-
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
-2 -1 0 1 2 3 4
dete
ctio
n ef
ficie
ncy
neutron energy[10x eV]
1/40eV
7
8
2.3
2.3.1
RPMTenergy spectrometer
10
-
count rate
pulse-shape discrimination
2.3.2 RPMT()
RPMT 9 [2, P1837,Fig. 2]RPMT 5
9 RPMT
0.40mm ZnS(Ag)/6LiF ( 1000) 12x y
3He
0.95nm RPMT 30%
60Co (1.173MeV 1.333MeV ) 109
DAQ(Data Acquisition System)x y lower level discrimination(LLD)
500ns20kHz
dead time 5%LLD
RPMT
11
-
2.3.3
RPMT
1. ZnS(Ag)/6LiF
n +6 Li + t (20)
2. t ZnS
XZnS conduction band exciton band
( 10) [3, P166,Fig. 7.7.]
10
3. exciton band exciton band ( exciton
) valence band ZnS Ag ZnS
exciton band valence band (Impurity traps)
exciton band valence band
4.
xx
I1, I2 I1/(I1 + I2) xy
0.7mm
(
)
2.3.4 Cd RPMT
CdRPMT 1ch
11 5.00mm Cd RPMT
12
0.5 160chY200ch X (14)Gaussian fitting 13
12
-
11
12 RPMT
13
14 X
6.0 1ch=0.234mm 0.001mm []
1ch=0.2325mm
2.4
13
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2.4.1
En
(1) Ep
(1) = 0 15 [4]
Ep =2.25[MeV] 3.0MeV
Ep =2.25[MeV] (1) En
16 [4] = 0 En 0.52MeV
15 Ep
14
-
16 En
2.4.2
(C2H4) 1MeV S
kBT
S
- S
hk eikz lh
b
lh = b hk (21)
b r0
b r0
(21)l kr0
r0 2.5fmS l = 0 kr0 < 1
Elab = 2Ecm =2h2k2
M