20 P4

2009 3 31

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

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

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