NGHIÊN CỨU PHẢN ỨNG BẮT NƠTRON NHIỆT Ag(n,y) Ag SỬ DỤNG CHÙM NƠTRON XUNG TRÊN MÁY GIA TỐC LINAC - LUẬN VĂN VẬT LÝ HẠT NHÂN

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MỤC LỤC
LỜI CẢM ƠN.......................................................................................................3
DANH MỤC ĐỒ THỊ VÀ BẢNG........................................................................6
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CHƯƠNG 3: t`T QUẢ THv
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TÀI LIaU THAM
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LỜI CẢM ƠN

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3

DANH MỤC ĐỒ THỊ VÀ BẢNG

Hình 1.1: Phổ nơtron của nguồn PuBe và nguồn AmBe
Hình 1.2. Phổ nơtron của nguồn phân hạch tự phát

252

Cf

Hình 1.3 Phổ nơtron
nơtron tạo ra trong
trong ! ph"n #ng
Hình 1.4$ Phổ nơtron %&nh ra t' (&a Pu) * +h& (,n ph" (-& ch.m nơtron c/ n0ng

1ng 35 4e
Hình 1.5. 67nh "nh

m&nh h8a ph"n #ng (,t nơtron nh&9t

Hình 1.6. ơ ;ồ phân r< của hạt nhân (,t notron) A = > n ? A>@ =
Hình 1.7 $ &t &9n (,t nơtron nh&9t của ph"n #ng @DE AgFn)GH@@Dm Ag
Hình2.1. ơ ;ồ

mIu phâ
phânn tJch +Jch

Hình2.2. ơ ;ồ (K trJ thJ ngh&9m +Jch hoạt mIu
Hình2.3$ ơ ;ồ phân r< của
Hình 2.4$

@@Dm

Ag

69 phân tJch phổ gamm
gamm

Hình 2.5 Phổ gamma
gamma của mIu phân tJc
tJchh Lác ;Mnh (Nng phOn mm Qamma
Qamma

&%%&on
Hình 2.6 $ R1Sng cong h&9u %uTt gh& ;Unh Vuang ;&9n của ;Wtectơ (án In 6PQe

FXYZCH
Hình 3.1 Phổ gamma ;[c tr1ng phát ra t' mIu Au) thS& g&an +Jch hoạt 3h) thS&

g&an phơ&
phơ& \E$5h) thS&
thS& g&an ;o 5 ph]t$
Hình 3.2 Phổ gamma ;[c tr1ng phát ra t' mIu Ag) thS& g&an +Jch hoạt 3h) thS&

g&an phơ&
phơ& 2\$^^ h) thS& g&an ;o @5h$
Hình 3.3 Phổ gamma ;[c tr1ng phát ra t' mIu _n) thS& g&an ch&u 3h) thS& g&an

phơ& \$5h)
\$5h) thS& g&an
g&an ;o 2 ph]t
ph]t

Hình 3.3 a& +hác g&`a +t Vu" tJnh toán trong un v0n và các +t Vu" tJnh toán

của các tác g&" +hác

4

Bảng 1.1 4bt %K nguồn
nguồn nơtron
nơtron ;ồng vM F) nH
Bảng 1.2$ Jnh chTt của mbt %K vt &9u àm chm nơtron
Bảng 2.2 Các g&á trM của hàm +hdp h&9u %uTt gh&$
Bảng 3.1 Các ph"n #ng ch&m (,t nơtron và mbt %K ;[c tr1ng$
Bảng 3.2 69 %K tự hTp th t&a gamma của mIu Au) Ag
Bảng 3.3 Q&á trM %a& %K thực ngh&9m Lác ;Mnh t&t &9n ph"n #ng ch&m (,t

nơtron nh&9t @E AuFn)GH@E^ Au
Bảng 3.4$ Các g&á trM t&t &9n ph"n #ng của các thJ ngh&9m Lác ;Mnh t&t &9n

ph"n #ng ch&m (,t nơtro
nơtronn

5

MỞ ĐẦU

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6

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7

CHƯƠNG 1: TỔNG QUAN VỀ PHẢN NG H!T NH"N #$%&' VÀ
NGUỒN NƠT()N
1*1 N+,-.$ /0 $23$ $+,-.$
@$@$@ ơtron
N,-/%  >- Z>m%2 ]%2 [<% -c8>& 8h Z>l< y%2 F†%2 1.6JO  1 ‹5J Z2&
o<% F†%2 ’ 8>“% ”
” F†%2 1. N,-/%
N,-/% 8>p F% -/%2 >- %>% F% 0Œ%2. – -%2
-%2
->7< -q S/& %,-/%

%,-/% >% g

−¿¿

& 0;< ->u< 2<% ol%2 ++1.O $1O( 2<E. Q7 -f%>

β

>% g 89 %,-/% -/ ->%> /-/% o
o::
−¿ + v
¿
n → p+ e

T/%2 [h ‹  8-/% 0

~
v

$1.1(

 >% %,-<%m. T
0
->m%2
y%2
898h%,-/%
>ˆ>%
->j88><
0/->%>

%n%2878
y%2
8 %,-/%. Cn% 8 0/
%n%2
y%2
%,-/%
->‡ [y8
/< o:
• N,-/% %>: %n%2
%n%2 y%2 --‰‰  ‚ .5O V
• N,-/% %><-: 8% F†%2 %><- 0;< ]m< -u%2 %2 Y%>& %n%2 y%2 8h
78 o?- ;% %>?-  5/C  .5O V& >% Fl M—<% ] j%2 -;<
Z>/%2 .5 V.
• N,-/% -}% %><-:
%><-: %n%2 
y%2
y%2 -‰ .5O
.5O V ‚ 1 V˜
• N,-/% 8j%2 >%2:
>%2: -‰ .1 ‚ 3 V
• N,-/% %><- %n%2 y%2 -‰ 1 V ‚ 1 V&
V& [m< Z>< }% -;< 1ZV $-ƒE ->/
-‰%2 [\%> %2>Š(
• N,-/% -%2 2<% %†] 2<Œ %,-/% %><- 0 %,-/% -}% %><-& %n%2
y%2 -‰ 0< V [R% .O MV.
• N,-/% -}% CS]<]: %,-/% c- F\ >? ->ˆ F< CS& %n%2 y%2 ;% >,%
.O V.
• N,-/% %>%> %n%2 y%2 ;% >,% .1 V&
V& .1 MV >/K8 1 MV -;< 5
MV $-ƒE ->/ [\%> %2>Š(.

• N,-/% o<} %>%>
%>%> $-,%2 [[l<
l< -c%>(: %n%2 y%2
y%2 ;% >,% 5 MV.
MV.
• N,-/% >% >8>: [y8 -/  -‰ Y7 -f%> >% >8> >- %>%& %n%2
y%2 -‰ 1V ‚ 1O MV& 78 o?- ;% %>?- .+ MV& -%2 Ff%> Z>/%2
5 MV.
• N,-/% -/%2 { >% %2 %
%n%2
n%2 y%2 -‰ .1 ‚ 1O MV.
MV.

8

@$@$2 guồn nơtron
a$ guồn nơtron ;ồng vM
N24% %,-/% [4%2 0\ F/ 24] F /< 8>c%>: %24% Sƒ%2 >% %2 $&
%(& $'&%( 0 %24% >% >8> $Ž& %(. C78 ->] ol Y% -k%2 [l< 0;< 878 %24%
%,-/% [4%2 0\  o?- y%2 >% %2 >7- %,-/% & >X %,-/% & %n%2 y%2 878
F8  & '&
'& ->u< 2<%
2<% ol%2 89
89 878 [4%2 00\\ 
Đl< 0;< /< %24% $& %(& ]j- ol [4%2 0\ >h%2  8h [K8 -c%> >% g &
878 >-  2E  >% %2 >- %>% $%& ( -/  %,-/%. ĐE 8>c%>  8, o [‡ -/
%}% 878 %24% [4%2 0\ F†%2 878> > -j% [4%2 0\ >7-   0;< 878 0=- < ->c8>

>y. N>Œ%2 %24% [4%2 0\ >7-  ->u%2  556)& 53& 5@1A]  B ->u%2
[y8 8>k% ] F< 8>/ o?- y%2 %,-/% ;% %>?-. %,-/% [y8 -/  8>9 ER -‰
>% >- %>% o:
4
2

12

9

H e + 4 B e → 6C + n + 5.71 MeV

$1.5(

T/%2 878 %24% [4%2 0\ $& %( S/ 878 >-  8h %n%2 y%2 Z>78 %> 0
%n%2 y%2 89 8>w%2 F\ oE 2<] -/%2 ]m< -u%2 0=- 8>?- %24% -;8 Z><
>% %2 E . D/ [h >X %,-/% 89 %24% [4%2 0\ $& %(  >X <}% -ˆ8 -‰
0ƒ%2 %><- -;< Z>/%2 1 MV. Hf%> 1.1  >X %,-/% -‰ %24% [4%2 0\  ‚ B
/< B$
B$&& %(. B%2 1.1  [K8 -%2
-%2 8, F% 89 ]j- ol %2
%24%
4% %,-/%
%,-/% [4%2 0\
/< $& %(.

Hình 1.1$ Phổ nơtron t' nguồn ;ồng vM Pu  Be
9

Đl< 0;< %24% >7- %,-/% $'& %( ->u%2 o€ Sˆ%2 878 /< %24% 15@|F&
5@
N& 1@L& J5 G& 8h %n%2 y%2 [R% Z>/%2 5 ‚ 3 MV 0 ->u%2 8>p o€ Sˆ%2
>< /< F< %>™  B 0 5H Y 878 >% %2 >- %>%: B$'& %(+B 0 y%2
;% >,% %2~%2 >% %2 >- %>% $'& %( ->f >W %> %>=% [y8 %,-/% [,% %n%2
S/ F8  2]] F\ ]?- %n%2 y%2
?- c- -/%2 ]m< -u%2 0=- 8>?-. |?- y%2
O
89 /< %24% %E 8>p Z>/%2 1 %˜o.
N24% [4%2 0\ >% >8> -q >7- S/ ]j- ol >- %>% %K%2 -q [j%2 >%
8>< 0 -/%2 Y7 -f%> >% >8> -q >7- o<%>  %,-/%. N24% >% >8> -q
>7- ->u%2 o€ Sˆ%2  %24% 5O5CŽ. N24% 5O5CŽ 0 878 %24% </% >% >8> -q
>7- Z>78 [y8
[y8 -/  F†%2 878>
878> 8>2E}% -l %<
%< >/K8 878 %2
%2E}%
E}% -l
o<} %< Z>78 F< %,-/% -/%2 { >% %2& %n%2 y%2 -%2 Ff%> Z>/%2 1.O
MV $>f%> 1.5(.
|?- y%2 89 %24% %,-/% 5O5CŽ 8h ->‡ }% [R% 1  %˜o. TE %><}% ->u<
2<% F7% g 8>p Z>/%2 5.6@O %n]& [E  >% 8>R 89 %24% /< %E.

Hình 1.2. Phổ nơtron của nguồn phân hạch tự phát

252

Cf

($ guồn nơtron t' các ! ph"n #ng hạt nhân
N,-/% o<%>  -‰ 878 { >% %2 >- %>% o<%>  -‰ Y7 -f%> >% >8>
89 878 %2E}% -l o<} %< ->m%2 Y 878 >% %2 >- %>% SE 8>E‡%. t><
>- %>%
%<
ZR->/K8
>y F
0;<%,-/%.
]j- >-C78
%>%
8/% o<%>
oš -/
8/%0;<
$]%>
>%
>8>(
0 ><
%,-/%
 
<><
-<R>-ˆ8%>%
ZR- >y
878
10

>- %>% o<} %< Z>78 0 >% %2 SE 8>E‡% < -< %,-/%
Z>78. C78 %,-/% >% >8> F/ 24] >< /< %,-/% -8 ->u< o<%>  -‰ >% %2
>% >8> 0 %,-/% -› o<%>  ]j% >,% oo// 0;< ->u<
->u< [<‡] >%
>% >8>.
1
1
252
phânh
phânhạcch
h
U →0 n + 0 n + m"nh
+ ¿92
1
0

n¿

C78 %,-/% -8 ->u< 8><R] œ -/%2 ol 878 %,-/% >% >8>. C78 %,-/%
%E [y8 o<%>  -‰ Y7 -f%> 878 >- %>% Zc8> ->c8> S/ -/%2 Y7 -f%> -/ [z<
%n%2 y%2 0;< 878 %8/% Z>78 8>w%2 8h %n%2 y%2 0y- Y %n%2 y%2 <}%
ZR- -/%2 >- %>%. T/%2 Z>< [h 878 %,-/% -› 8>p 8><R] Z>m%2 -;< 1œ -/%2 ol
878 %,-/% >% >8> -E %><}% < [h%2 0< -{ ?- Y% -k%2 -/%2 0<8 [<
Z><‡% 878 >% %2 SE 8>E%. N,-/% -› ?- ><% Z>< 878 ]%> >% >8>
>% >}8> >% g & >- %>%
%>% >% >
>8>
8> o [h 8h %n%2 y%2 Zc8> ->c8> [9
[9 ;%
[‡ >7- %,-/% -›. T>u< 2<% -› 89 %,-/% [y8 78 [\%> F†%2 ->u< 2<% ol%2

89 878
>% >8> >% g . Hf%> 1.3  >X %,-/% [K8 -%2 o<%>  -‰ {
>%
%2]%>
>- %>%.
Bảng 1.1 4bt %K nguồn
nguồn nơtron
nơtron ;ồng vM F) nH

51

/B

Nn%2 y%2
y%2 -%2 Ff
Ff%>
%> 89
%,-/% $MV(
@.5

51

/B

5.O

13+ %2E

556

)B

3.

16 %n]

556

)B

3

16 %n]

53

B

@.O

5@11 %n]

5@1

A]B

@

@35.5 %n]

5@5

C]B

O

165.+ %2E

N24% %,-/%
%,-/%

11

T>u< 2<% F7% g
13+ %2E

Hình 1.3 Phổ nơtron
nơtron tạo ra trong
trong ! ph"n #ng

c$ guồn nơtron t' mái g&a tKc
4ái phát nơtro
nơtronn @34e:
@34e:
M7E >7- %,-/% ->q8 8>?-  %24% %,-/% [,% %n%2 8h %n%2 y%2 0
8u%2 [j ;%. M7E >7- %,-/% Z>78 0;< %24% %,-/% >% >8> 0 %24%
%,-/% [4%2 0\  8>i  Sq -}% 878 >% %2 >- %>% ] >- %>% -;< ->u%2

 878 >- %>% [,-< $ 5H& D( [y8 FP% 0/ 878 F< Z>78 %> ->u%2  -<-<
$3H& T( >/K8 D 0 >7-  %,-/% 8h %n%2 y%2 [,% %n%2 78 [\%>. Đ<% ->R 2<
-l8 ->? $8~ 0< -n] ZV(& -/ ->%> %,-/% ->/ 878 >% %2 o:
5
H$S&%(3Hž Q Ÿ 3.56+ MV
3
H$S&%(@Hž Q Ÿ 1J.O++ MV
>% %2 5H$S&%(3H 8h -O F%& S/ [h -/  8>ƒ] %,-/% %>%> 0;< o?- y%2 ;%. T/%2 >% %2 D‹D
8>/ %n%2 y%2 8/ $13‹1OMV(. |?- y%2 %,-/% >ˆ ->j8 0/ %n%2 y%2
8>ƒ] [,-<. Nn%2 y%2 89 8>ƒ] %,-/% >7-  >ˆ ->j8 0/ %n%2 y%2
8>ƒ] [,-< 0 2h8 >7-  89 %,-/%.
ơtronn phát ra tt'' mái g&a tKc eectr
ơtro
eectron
on
M7E 2< -l8  ]j- -><R- F\ 8h ->‡ -/  8>ƒ] 8-/% %n%2 y%2 8/.
B†%2 878> o€ Sˆ%2 -,%2 -78 89 8-/% 0;< [g [y8 2< -l8 0;< 0=- 8>?- 8h ->‡
-/  878 %24% F8  >g] 8h %n%2 y%2 8/ 0 8u%2 [j ;%. %,-/% [y8
-/ ->%> S/ -,%2 -78 89 F8  >g] 0;< >- %>% F<.
C>ƒ] %,-/%
%,-/% -}% ]7E 2<
2< -l8 [y8 -/  -}%
-}% ]7E 2< -l8 -ER%
-ER% -c%>
[y8 -/  ->/ 878 Y7 -f%> o: $1( C>ƒ] 8-/% [g [y8 2< -l8 FP% 0/
]j- F< F8  >g] ] F†%2 Z<] /< %K%2 [‡ -/  F8  >g]. $5( C78 F8
12

 >g] 2E >% %2 %2 Y%2 >- %>% $'& %( 0;< 878 F< [‡ -/  ]j- >E
%>< %,-/%. C78 >% %2 Y%2 >- %>%  878 >% %2 %2~%2. Vf 0=E [‡
2E  >% %2 8W% 8>ƒ] %,-/% 8h %n%2 y%2 [9 ;%& ->u%2  878 >/-/%
[y8 -/  -‰ 878 ]7E 2< -l8. Đl< 0;< 878 >- %>% %K%2 >% %2 $'& %( [h%2
0< -{ 8>c%> -/%2 0ƒ%2 8j%2 >%2 Z>X%2 4. >W% ;% 878 %,-/% o<%>  ->/
8, 8>R FE >,<& 8>w%2 8h %n%2 y%2 ->? 0 >% Fl 2W% %> [%2 >;%2. Mj >W% %>z %,-/% %n%2 y%2 8/ [y8 -/  F†%2 878> -,%2 -78 -q8 -8-/% 0 >/-/% >g] 0;< >- %>% F<. T% F< %>z >/% 1˜13J W% o/ 0;< -,%2 -78 89 >/-/% 0;< >- %>% F< %}%
-,%2 -78 %E [h%2 0< -{ -> ER. C78 %,-/% ->u%2 [y8 -/  F†%2 878>
FP% -q8 -<R 8>ƒ] 8-/% %n%2 y%2 8/ 0 878 F< SE ] F†%2 Z<] /<
%K%2 >/K8 Sƒ%2 8>ƒ] F8  >g] FP% 0/ F< -> 8? [K- >c o F< >g]. C78
0=- < %K%2 0;< ol ¡ ;% 8h %n%2 y%2 <}% ZR- %,-/% ->? 0 ]=- [j 0=- 8>?8/ %}% 8>/ o?- y%2 >7- %,-/% ;%. )<}%2 [l< -u%2 >y 89 B 0 D 8h ol
Z>l< ¡ %>z& -E %><}% %n%2 y%2 <}% ZR- %,-/% 89 8>w%2 ->? $1.6J MV [l<
0;< B 0 5.55 MV [l< 0;< D( %}% B 0 D ->u%2 [y8 o€ Sˆ%2 ] F< 89
%24% Y%2 %,-/%. Nn%2 y%2 89 %,-/% o<%>  -‰ 878 >% %2 Y%2 >%>% >ˆ ->j8 8>9 ER 0/ %n%2 y%2 89 F8  >g] >E %n%2 y%2 89
8>ƒ] 8-/% 0 ol Z>l< 89 >- %>% F<.

Hình 1.4$ Phổ nơtron %&nh ra t' (&a Pu) * +h& (,n ph" (-& ch.m nơtron c/ n0ng

1ng 35 4e
1*4 T5+$ ,67 789 $+,-.$ /; /<, 7=>,
C78 %,-/%
%,-/% o<%> 
 8h >X
>X %n%2 y%2
y%2 <}% -ˆ8& -/%2
-/%2 [h %,-/%
%,-/% %><%><8><R] ]j- -p  %>z. t>< %,-/%
%,-/% 0 8>] 0;< 878 >- %>% -/%2 ]m< -u

-u%2&
%2& -l8
13

[j 89 8>w%2 2<] SW% -;< %n%2 y%2 %><- $.5O V(. Q7 -f%> 2<] %n%2
y%2
y
%2 89 %,-
%,-/%
/% 8>9 ER S/ Y7 -f%>
-f%> -7%  [% >4< 0 [y8 2k<  oq %><>h.
>h
. C78 0=- <
<
 Sƒ%2
Sƒ%2 [‡ %><%><- >h %,-
%,-/%
/% [y8
[y8 2k<  8>?8>?- ]
] 8>=]
8>=]
$]/S$]/S
-/(.
/(. Mj- 8>?8>?- -l-  2<] -l8 [j %,-/%
%,-/% -l- 0;< ol 0 8>
8>]
] c- %>%2

Z>m%2 >? ->ˆ 8>w%2. C>?- ] 8>=]  -%2 8h 878 -c%> 8>?- o:
• T• T• Tl8 [j ]?- %,-/% -}% ]j- 0 8>] ;%
Đj 2<] %n%2 y%2 /2 -%2 Ff%> $ ξ ¿  ->;8 [/ -l8 [j ]?- %n%2
y%2 -%2 Ff%> -}% ]i< 0 8>]& [y8 F<‡ S<›% %> o:
E o
( A −1 )2 A −1
ξ = ln E o−ln En =ln
ln
=1 +
A +1
E n
2 A

( )

$1.1@(

T/%2 [h:
•
•

•/  %n%2 y%2 F% [W 89 %,-/%
•%  %n%2 y%2 89 %,-/% o 0 8>]

Đj 2<] %n%2 y%2 -%2 Ff%>
%n%2 ] 8>=] %,-/% 89 ]i< 0=- <.

G<7 -\

ξ

ξ

 ]j- >†%2 ol 0 [K8 -%2 8>/ Z>

[l< 0;< ]j- ol 0=- < %>™ [y8 <- Z} -/%2 F%2 1.5.

Bảng 1.2$ Jnh chTt của mbt %K vt &9u àm chm nơtron

V=- <
HES/

|l 0 8>] [‡ %><>h $N(
1+

ξ

1

Tp ol ] 8>=]
$N)(
66

H
6JO+5

D5/*
-/%
..J55OJ
51O
¢
D5*
.O1
3O
£O+5
H
.@5O
@3
@
B
.5
+6
1@6
C8F/%
.1O+
11@
5J3
*E
.15
1O
@+J
Đl< 0;< 878 8>?- 8h ol Z>l< ;% >,% 1 ->f 8h ->‡ o€ Sˆ%2 878 F<‡ ->8
? p o [‡ -c%> 2<7 -\ 89

ξ

ξ=

:
2
2

$1.1O(

A + 3

|l 0 8>] 8W% -><R->2<] %n%2 y%2
y%2 %,-/%
%,-/% -‰ %n%2
%n%2 y%2 •/ [R%
14

%n%2 y%2 •% 8h ->‡ -c%> F†%2 F<‡ ->8 o:
N =

ln

ln Eo −ln E n

=

ξ

1+

( )
Eo
En

( A −1 )2

A −1

2 A

A + 1

ln

$1.16(

( )

Đl< 0;< 878 >- %>% %>™ ->f ol 0 8>] 8h ->‡ -c%> F†%2 F<‡ ->8 o:
N =

(

A
2

1
3

+ +

) ( )

E o
1
ln
E n
18 A

$1.1J(

0ng %uTt àm chm vj mk:
MK8 Sƒ [j 2<] %n%2 y%2 /2 -%2 Ff%>  ->;8 [/ Z> %n%2 ]
8>=] %,-/% 89 0=- <& %>%2
%>%2 %h Z>m%2 ->‡ [[7%>
7%> 2<7 [y8 -?- 8 878 -c%>
-c%> 8>?8W% ->%n%2 o?- ] 8>=] 0Š ]m $M|D& ]8/o8/<8 o/—<%2 S/—% /—(.
Nn%2 o?- ]
] 8>=] 0Š ]m  -c8> 89 [j 22<]
<] %n%2 y%2 /2
/2 -%2 Ff%>
Ff%>
$ ξ ¿ 0 - MSDP=ξ Σ s

$1.1+(

l %K àm chm Fmoerat&ng rat&oH
Nn%2 o?- ] 8>=] 0Š ]m 8>/ F<R- -l8 [j ] 8>=] %,-/% -/%2 0=<& %>%2 8>  2<< [WE [9 >< o?- ] 8>=] 89 0=- <. Vc Sˆ B//% 
%2E}% -l 8h [j 2<] %n%2 y%2 /2 ?- ;%& %n%2 o?- ] 8>=] ?- ;% %>%2
Z> %n%2 %><- >h -4< S/ 78 o?- >? ->ˆ %,-/% %><- ?- ;%.
y%2
[y8
[‡ [7%>
o?-0Š89
]S<%
8>=]
-p ol
8>=]Đ<
$M)(.
ĐE
 -po€olSˆ%2
89 %n%2
o?-2<7
]><
8>=]
]m8>?0 -<R>?->ˆ
0Š ]
]m
Σ a

:

MR =

ξ Σs

$1.1(

Σ a

L->2E: M8 [j ] 8>=] %,-/%
L->2E  >] >ˆ ->j8 %n%2 y%2 • 89 %,-/% ->/ F<‡ ->8 o:
U ( ( E
E )= ln

Eo

$1.5(

E

T/%2 [h: •/  %n%2 y%2 F% [W
[W 89 %,-/% o<%> & •  %n%2 y%2
y%2 89
%,-/% o Z>< [y8 ] 8>=].
15

L->2E -n%2 Z>< • 2<].
Q/c tán Lạ trung (7nh của nơtron :

Gh8 -7%  -%2 Ff%>
Ff%> 89 %,-/%
%,-/% -}% 8>?
8>?-- ] 8>=] [y8 -c%> F<
F< 8m%2
->8:
´ θ=
cos

2
3 A

$1.51(

V;< HES/ $AŸ1(& ?- ><% oq -7%  F?- [%2 >;%2 0 >c -;8 ¤ - 0f
´ θ =0.666
cos

o
0 θ´ = 48 .

Rb à& àm
àm chm:
Đj S< ] 8>=]  [j S< Yg%2
Yg%2 [u%2 ] %,-/%
%,-/% [< [y8 -/%2 8>?8>?- ]
8>=] [‡ %n%2 y%2 •/ F% [W 89
89 %,-/%
%,-/% 2<] l%2
l%2 %n%2

%n%2 y%2
y%2 •  & - 2k<
τ 

 -X< %,-/% %><-& ->f [< y%2 √ τ  [y8 2k<  [j S< ] 8>=].

Đl< 0;< 8>?- ] 8>=]  %;8& %n%2 y%2 • / Ÿ 5 MV& •T Ÿ .5O V&
Ÿ 5J 8]5& oE 2<] [j S< ] 8>=] oš : √ τ  ŸO.5 8].

τ 

1*? P=@$ $ =, $=$  EF; $+,-.$
D/ Z>m%2 ]%2 [<% -c8> %}% Z>< 0/ ]m< -u%2 0=- 8>?- ->f %,-/%
-,%2 -78 ?- ER 0;< 878 8-/%. T,%2 -78 89 %,-/% 8>9 ER  0;< >- %>%.
T,%2 -78 89 %,-/% 0;< 0=- 8>?- 8>9 ER  S/ Y7 -f%> -7%  [% >4<& -7% 
Z>m%2 [% >4< 0 878 >% %2 >- %>%. T,%2 -78 89 %,-/% 0;< >- %>% 8>9
ER >ˆ ->j8 0/ %n%2 y%2 89 8>w%2.
@$\$@ Ph"n #ng tạo proton Fn)pH
>% %2 $%&( E  0;< %,-/% 8h %n%2 y%2 8~ .O ‚ 1MV.
( A ! " ) + n → ( A ! " −1 ) + p

$1.55(

L/< >% %2 %E ->u%2 -z %><- Q¢ 0f ] % ¢ ] . NR Q¥1 ->f ¦Q¦ # 1
MV. V %,-/% 8W% >< 8h %n%2 y%2 8/ [‡ /-/% 8h ->‡ 0y- Y >%2 /
->R C//]F ->/7- Z>z< >- %>%.
Vc Sˆ: %  35|

→

35

   0;< Q Ÿ ‹.5 MV

>% %2 %E [y8 o€ Sˆ%2 -/%2 0<8 2>< %>=% %,-/% >% >8> -/%2 ->c
%2><] [W -<}% 0 >% >8> 0 878 >- %>% %K%2.
@$\$2
Ph"n
hạt o€ Sˆ%2 j%2 g< -/%2 0=-  >- %>%. >% %2 /<
>%
%2#ng
$%& tạo
( [y8
16

%E [{< >z< %,-/% 8h %n%2 y%2 -‰ .O ‚ 1 MV.
( A ! " ) + n → ( A −3, " −2 )+ 42 H e

$1.53(

TE %><}% -/%2 %>< -u%2 >y& %n%2 y%2 >% %2 ?- 8/& ] >%2
TE
/ C//]F < ->?& S/ [h 78 o?- -,%2 -78 0;< %,-/% %><- 8/. Vc Sˆ:
+¿4 He ! $= 4.5 MeV
+ ¿6 %& → ❑3 H ¿
n¿
10

7

4

n + ❑ B → %& + ❑ H e !$ =2.8 MeV

ĐE  878 >% %2 ->u%2 [y8 o€ Sˆ%2 [‡ 2>< %>=% %,-/% %><-.
@$\$\ Ph"n #ng phân hạch
t>< 878 >- %>% %K%2 $T>& & U& ( [y8 8>y%2 ¢ 1 MV& >/K8 %,-/% %><- [l< 0;< ]j- ol >- %>% o<} %<& ]j- >%>% %K%2 oš -78> ->%> >< ]%> >% >8> 8h ol Z>l< ->/ -p } 5:3
( A ! " ) + n → ( A 1 ! " 1 ) +( A2 ! " 2)

$1.5@(

T/%2 [h: A1  A5 Ÿ A  1ž ¡1  ¡5 Ÿ ¡
t<‡ >% %2 %E [y8 2k<  Z<‡ >% %2 >% >8> >- %>% Zc >< 
$%&Ž(.
>% %2 >% >8> [y8 o€ Sˆ%2 j%2 g< -/%2 Š%> 0q8 %n%2 y%2 >%>%.
@$2$3 Ph"n #ng tạo ra ha& ho[c nh&u nucecon
V;< %,-/% %n%2 y%2 ;% >,% 1 MV ->f 878 >% %2 $%& 5%(& $%& %(&
$%&3%( 8h ->‡ E . C78 >% %2 %E [y8 o€ Sˆ%2 j%2 g< 0;< %,-/% %>%>.
Vc Sˆ: %  63C

→

65C  5%& 0;< •%2~%2 Ÿ 1 MV.

L/< >% %2 $%& 5%( 8h %2~%2 8/ S/ %n%2 y%2 [‡ -78> 5 %88/% ;%
>,% %>< [l< 0;< -78> 1 %8/%. TE %><}% B  ]j- -u%2 >y [K8 F<-& 8h

%n%2 y%2 %2~%2 ?- ->? 8>p Z>/%2 5 MV:
9

4

n + ❑ B e → 2 ❑ H e + 2 n ! vd & E n'1

=2 MeV

n
'

a$án Lạ +hkng ;àn hồ&
T7%   Z>m%2 [% >4< Z>< %,-/% -,%2 -78 0;< 0=- 8>?-& -E% ]j- >W%
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18

Hình 1.5. 67nh "nh

m&nh h8a ph"n #ng (,t nơtron nh&9t
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F& )E0o
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24

CHƯƠNG 4: PHƯƠNG PHWP XWC ĐỊNH TIYT DIZN PHẢN NG
CHIYM B[T NƠT()N NHIZT
4*1 T$ 29$ /\ K=5+$ K=6K K=$ ,]7= O]7= =., $+,-.$ ^4?_
2$@$@ uá tr7nh phân r< ph/ng Lạ

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F< 8m%2 ->8:
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=

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3/

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Z>78 %>. Tc8> >% 8m%2 ->8
->8 -}% - -> [y8 ol %2E}% -€ -< ->u< [<‡] - >ˆ
->j8 0/ ol %2E}% -€ [K8 -%2 -/%2 ]s:
¿

− 7/

N ( ( / )= N o . e

T/%2 [h

¿

N o

$5.5(

 ol %2E}% -€ -< ->u< [<‡] - Ÿ .

2$@$2 Chu& phân r<
T/%2 ]j- ol -u%2 >y >- %>% >% g Z>m%2 -/ ->%> >- %>% F%
] -/ ->%> ]j- 8>i< >% g. Mi< ]j- 8>i< >% g [ ZR- ->w8 F< ]j- >%>% F%. Mj- 8>i< >% g [<‡% >f%> [y8 8>/ -/%2 >f%> o:

T/%2 [h ) F<‡ S<›% >- %>% >% g 0 |  >- %>% F%. G< o€ †%2
ol %2E}% -€ -< ->u< [<‡] -Ÿ 8>p 

R1 = 0

25

. T 8h:

NGHIÊN CỨU PHẢN ỨNG BẮT NƠTRON NHIỆT Ag(n,y) Ag SỬ DỤNG CHÙM NƠTRON XUNG TRÊN MÁY GIA TỐC LINAC - LUẬN VĂN VẬT LÝ HẠT NHÂN

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