Đồng vị 14C và biến động của khí hậu ở Việt Nam

ĐẠI HỌC QUỐC GIA HÀ NỘI
TRƯỜNG ĐẠI HỌC KHOA HỌC TỰ NHIÊN





NGUYỄN THỊ HƯỜNG




ĐỒNG VỊ
14
C VÀ BIẾN ĐỘNG CỦA KHÍ HẬU
Ở VIỆT NAM





LUẬN VĂN THẠC SĨ KHOA HỌC







Hà Nội - 2012

ĐẠI HỌC QUỐC GIA HÀ NỘI
TRƯỜNG ĐẠI HỌC KHOA HỌC TỰ NHIÊN




NGUYỄN THỊ HƯỜNG


ĐỒNG VỊ
14
C VÀ BIẾN ĐỘNG CỦA KHÍ HẬU
Ở VIỆT NAM




LUẬN VĂN THẠC SĨ KHOA HỌC


NGƯỜI HƯỚNG DẪN KHOA HỌC: PGS. TS. NGUYỄN QUANG MIÊN

Luận văn được thực hiện tại Viện Khảo cổ, Viện Khoa học Xã hội Việt Nam





Hà Nội – 2012

Chuyên ngành:

Vật lý hạt nhân, nguyên tử và năng lượng cao
Mã số :

60 44 05
Luận văn thạc sỹ 

MỤC LỤC
MỞ ĐẦU 6
1 CHƢƠNG 1. TỔNG QUAN TÌNH HÌNH NGHIÊN CỨU 8
1.1  8
1.1.1 
14
 8
1.1.2 
14
 9
1.1.3  10
1.2  11
1.2.1 
(GPC) 11
1.2.2  11
1.2.3  detector  12
1.3 
14
detector  13
1.3.1 detector  13
1.3.2 Detector  15
1.4  19

2 CHƢƠNG 2. THỰC NGHIỆM 20
2.1 
Tri-carb 2770TR/SL 20
2.1.1  20
2.1.2  21
2.1.3  23
2.2 detector -carb 2770TR/SL
28
2.3 -carb 2770TR/SL 29
2.4 
14
 30
2.4.1  30
2.4.2  32
2.4.3  33
2.4.4  40
2.4.5 -carb 2770TR/SL 40
Luận văn thạc sỹ 

3 Chƣơng 3 - KẾT QUẢ VÀ THẢO LUẬN 46
3.1  46
3.1.1  46
3.1.2  48
3.1.3  50
3.2  51
3.3 
14
 52
3.4  58
KẾT LUẬN 61

TÀI LIỆU THAM KHẢO 62


Luận văn thạc sỹ 

DANH MỤC HÌNH
Hình 1.1. 
14

 9
Hình 1.2. S 
14
detector  15
Hình 1.3. S detector  17
Hình 2.1. S 
14

-carb 2770TR/SL 20
Hình 2.2. S  24
Hình 2.3  25
Hình 2.4. 
14
-carb 2770TR/SL 31
Hình 2.5 32
Hình 2.6.  34
Hình 2.7. 
2
 34
Hình 2.8 t  35


2
 35
Hình 2.10. 
2
 36
Hình 2.11 38
Hình 1.12.  39
Hình 2.13. Detector -carb2770TR/SL 40
Hình 2.14. 
14
 41
Hình 2.15. S -carb2770 TR/SL 42
Hình 2.16  43
Hình 2.17 43
Hình 2.18 43
Hình 2.19-1 44
Hình 2.20 44
Hình 3.1
14

 56
Hình 3.2 58
Hình 3.3. 
2
tro 60




Luận văn thạc sỹ 

DANH MỤC BẢNG
Bảng 1.1
14

 12
Bảng 2.1:  31
Bảng 2.2 39
Bảng 2.3 45
Bảng 2.4.  45
Bảng 2.5.   45
Bảng 2.6-1 46
Bảng 2.7.  46
Bảng 3.1.  48
Bảng 3.2.  49
Bảng 3.3 52
Bảng 3.4. 
14
C/
12
C 52
Bảng 3.5 54
Bảng 3.6 55
Bảng 3.7
0
 56

Luận văn thạc sỹ 

MỞ ĐẦU








2

 

 




(CO
2

 

-

,


 

 

     
18
         

14

 
Luận văn thạc sỹ 


14


                

Ph


 i
       -      


14

6
H
6




Đồng vị
14
C và biến động cổ khí hậu ở Việt Nam” 





 


Luận văn thạc sỹ 

1 CHƢƠNG 1. TỔNG QUAN TÌNH HÌNH NGHIÊN CỨU
1.1 Cơ sở khoa học của phương pháp
1.1.1 Sự hình thành của đồng vị
14
C trong tự nhiên


 , c-12 (
12
C), carbon-13
(
13
C), carbon-14 (
14

12
C,
13


12

13


14


-10


-


14


12

13

14
C



14


14

e
eNC



14
7
14
6
(1.1)
 (1.1) 










.
 
14



 (





14 14
76

n N C p 0,6MeV   
(1.2)


14
C



 





 

2


2

14
CO
2


 (

1 






2






 1 


2





14
C).

2
 , 






14







2
trong k. 








, 

14






 , 








 .

2
tron














Luận văn thạc sỹ 

 (CO
3
2-
), 



14



n


Hình 1.1. 
14

-based Dating in Archaeology)

1.1.2 Biến thiên hàm lượng
14
C theo thời gian

14
C

14
       
14
 
14
        

14


14


14
 

CO
2



14
C/
12


Luận văn thạc sỹ 

1212
14
10
3,1

C
C

             
         



14

      

14
C) tr

1.1.3 Cơ sở của phương pháp

14
C/C
12

      


14

h:
A
t
= A
o
.e
-t
(1.4)
A
t

14


A
o

14

 
14
C.


14
C , 
14
C trong

, 

0


14
C trong

0


14

Luận văn thạc sỹ 

1.2 Các phương pháp đo đồng vị phóng xạ

14

,  Gas Prportional Counting),
detector  
 Accelarator Mass Spectro).
1.2.1 Kỹ thuật đo hàm lượng
14
C bằng phương pháp ống đếm chứa khí (GPC)


14

-


4


v
14


14





 
1.2.2 Kỹ thuật đo đồng vị
14
C bằng phổ kế gia tốc khối lượng (AMS)

                 
carbon tr     
2
           



12
C,
13

14
 



14

Luận văn thạc sỹ 

 






14
C 
1.2.3 Kỹ thuật đo hoạt độ
14
C bằng detector nhấp nháy lỏng
detector 


detector n

14



14
(AMS)

14
C qua

Bảng 1.1
nhau
TT
Đặc tính kinh tế và kỹ thuật
AMS
LSC
GPC
1



1mg
2,6g
2,6g
2


900
56,5
30
3

3,78
0,18
0,75
4


0,42
0,66
2,4
5




6

500$
250$

250$


Luận văn thạc sỹ 

 

14


1.3 Đo đồng vị
14
C bằng detector nhấp nháy
1.3.1 Giới thiệu về detector nhấp nháy







detector 


detector 
detector 

- 

-            


- 
- 

- 

   detector          

Luận văn thạc sỹ 

detector 

 
1. 
2. 

3.  
4. 

5. 
6. 


 
detector 

, 
 






-9

-6


detector 

          

detector 
Luận văn thạc sỹ 


1.3.2 Detector nhấp nháy lỏng


detector 


Hình 1.2. 
14
 detector 
1. detector 
2. 
3. 
4. 
5. 

detector
 detector

1.3.2.1. Chất dung môi

 



Luận văn thạc sỹ 

Khi 



 



             



14

- 

- Ph


- 

1.3.2.2. Chất phát quang
 


  




 

Luận văn thạc sỹ 



 
- 
- 
- 
- 
detector 



Hình 1.3detector 

1.3.2.3. Quá trình tạo xung sáng trong detector nhấp nháy lỏng
             

 


 

14

               
detector 



1. 
2. 
3. 
Luận văn thạc sỹ 

detector
 

              



 




1.3.2.4. Biến đổi photon thành xung điện










               

 

detector 


Luận văn thạc sỹ 



1.4 Những vấn đề quan tâm nghiên cứu của luận văn











:
-.
-
















14




, :
+ 






.
+ 
























-carb 2770TR/SL.
+ 






, 





.
Luận văn thạc sỹ 

2 CHƢƠNG 2. THỰC NGHIỆM
2.1 Quy trình phân tích hàm lượng trong mẫu môi trường sử dụng hệ đo
Tri-carb 2770TR/SL

Hình 2.1. 
14

Tri-carb 2770TR/SL
2.1.1 Thu thập mẫu


14
. , 
, 




 : , ,  ,  
nhau.



14
C tr-carb 2770TR/SL


14
C


Luận văn thạc sỹ 

2.1.2 Phân loại và làm sạch mẫu

 


2.1.2.1. Các loại tạp nhiễm có thể có trong mẫu nghiên cứu


- o 
- 


             









 

- 
- 
2.1.2.2. Các tạp nhiễm trong quá trình bảo quản mẫu nghiên cứu



Luận văn thạc sỹ 






     

: 






 

 



2.1.2.3. Tẩy tạp nhiễm trong mẫu


  

0
C trong

axit 


it HCl 1%.

   Akali  

0


Luận văn thạc sỹ 



  



2.1.3 Làm giàu mẫu bằng kỹ thuật benzen hóa

6
H
6

14




               


ng.



 
14
C

              


Luận văn thạc sỹ 


Hình 2.2. TASK BENZENE SYNTHESIZER


2.1.3.1. Tạo khí CO
2


2
:



2

(CO
2
) 
C + O
2
 CO
2
 (2.1)
 , 

 ,





