精确测量反应截面并利用反应

Qci = 1.15Ai1/3 (1 +1.565Ai−2/3 −1.04 Ai−4/3 )
Qci =
5 3 Rrms (i)
(i = 1, 2)
rp2 = 0.76 fm
u1987, S. Kox et al derived a formula by which the experimental results in the intermediate energy range can be reproduced.
S. Kox et al., Phys. Rev. C35 (1987) 1678
The asymmetry term to be related to the volume overlap of the colliding nuclei
σR
=
10π
R
2 int
(1
−
B
/
Ec .m. )
B
=
rc
(
Zt Z pe2
airplane electronics Future: Smaller electronics will
increase the problem, also at sea level Solution: Better knowledge about the nuclear ractions and interaction will help reducing the problem
• IMPCAS. Wang Qi, Sun Zhiyu, Bai Zhen, Zhang Xueying, Zhang Jie.
内容
1. 精确测量反应截面的意义.
1. 在医学上的应用 2. 在电子学设备防护上的应用 3. 在核结构方面的应用
2. 在日本的实验Ⅰ&Ⅱ 3. 在兰州实验的可能性. 4. 谢谢.
A 1/ 3 t
+
Ap1
/
3
)
，Rint
=
Rvol
+
Rsurf
Rvol = r0 ( At1/3 + Ap1/3 )
Rsurf
=
r0[1.85
A A 1/3 1/ 3
t
p
A 1/ 3 t
+
A 1/3 p
−
C( E)]
+
α Kox ( At − 2Zt )Z At Ap
p
This term imply the neutron skin excess
• It is important in applications
- Medicine - Astrophysics - Cosmic radiation effects on electronics - Transmutation of nuclear waste - Energy conversion - Nuclear structure
精确测量反应截面并利用反应 截面精确提取核密度
报告人:樊广伟 导师:徐望研究员
中科院上海应用物理研究所
参加小组
• SINAP. W. Xu, Pan Qiangyan, Xu Benji, Fan Guangwei
• Osaka Univ. M. Fukuda, D. Nishimura, M. Mihara, J. Komurasaki, R. Matsumiya, K. Matsuta
Here Rrms represent RMS charge radius
σR
= 10π R(R
−
D Ec.m.
)
D = 1.44Z1Z2MeVfm
R
= Q1
+ Q2
+
fE −1/ 3 c.m.
(
A11/
3
+
A21/ 3 )
Q12 = Qc21 − (5 / 3)rp2，f =1.169(bestvalue)
6
1.3. Application-Extract nuclear structure
Three typical formula u1984, S.K. Gupta et al developed the
strong absorption model ,and parameterized the σ. In the low energy range, the formula fit the experimental data well. S.R. Gupta et al., Z. Phys. A317 (1984) 75
1.1. Applications - Medicine
RELATIVE DOSE
100
BRAGG PEAK
80
60
PHOTONS
PROTONS 150 MeV
Co60
40
20
ELECTRONS 20 MeV
0
5
10
15
20
25
30
DEPTH IN TISSUE (cm)
5
1.2. Applications – Cosmic radiation effects
W.Q. Shen et al., Nucl. Phys. A491 (1989) 130
u1989, W. Q. Shen et al obtained a formula based on the Gupta’s formula and Kox‘s formula, try to explain the experimental results from the low to intermediate energy range.
Cosmic radiation
Drain
Gate
Source
N+ P-sub+-s+-+t-+-r+-+a-+t-+e-++--+(Si or Ge)
+-
+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-
Fra Baidu bibliotek
N+ +- +-
+
MOS-Transistor
Causes random re-programming or failure of digital electronics Today: Mainly a problem for
1. Why measure reaction cross sections?
• Reaction cross section = The total probability for a nonelastic reaction to occur.
• Reaction cross sections are sensitive to the size of the projectile and the target.