基于热核退激的路径分析对核耗散的研究

毛英臣 辽宁师范大学物理学院

2012 超重核合成与性质讨论会 , 兰州大学 , 2012 年 8 月

 

OutlinesYC

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Introduction

Theoretical Models

Results and Discussions

Summary

Introduction – Heavy-ion Nuclear ReactionYC

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Nuclear DissipationYC

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D. Hilscher, I.I. Gontchar and H. Rossner, Phys. Atom. Nucl. 57, 1353 (1994)

Theoretical results IYC

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J. Blocki, et al., Ann. Phys. 113, 330 (1978); H. Feldmeier, Rep. Prog. Phys. 50, 915 (1987)J. R. Nix and A. J. Sierk, Proc. Of the 6th Adriatic Conference in Nuclure Physics: Frontiers of Heavy-Ion Physics, Dubrovnik, Yugoslavia (1987), edited by N. Cindro et al. (Singapore, World Scientific, 1990), p. 333.S. Pal et al. Phys. Rev. C 63, 064603 (2001); ibids 63, 064603 (2001).G. Abal, et al., Nucl. Phys. A 683, 279 (2001).

One-Body Dissipation Theory + Wall and Window FormulismJ. Blocki et al.

Theoretical results IIYC

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H. Hofmann and P. J. Siemens, Nucl. Phys. A 257, 165 (1976); H. Hofmann, Phys. Rep. 284, 137 (1997) ; H. Hofmann, The physics of warm nuclei: with analogies to mesoscopic systems, Oxford, OUP, 2008

W. Nörenberg, Nucl. Phys. A 409, 191c (1983).

Dissipative Diabatic Dynamics by W. Nörenberg

Quantal Transport Theory by H. Hofmann et al.

Theoretical ModelsYC

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The Combined Dynamical Statistical Model (CDSM model)

In overdamped conditionIn overdamped condition ，， Langevin equation readsLangevin equation reads ：：1

( ),( ) (

( ))

V qdq Tt

dt M q Mq qb b= + G

¶-

¶

( )( ),

( ) ( )T S qdq T

tdt M q M qqb b

¶¶

= + G

P. FrP. Fröbrich, Nucl. Phys. A 787, 107c (2007)öbrich, Nucl. Phys. A 787, 107c (2007)

P. Fröbrich and I. I. Gontchar, Phys. Rep. 292, 131 (1998).

Important parameters IYC

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Entropy:

Temperature:

2/ 3( , ) ( )v s sa q A a A aA B q= +

Level density parameter (LDP):

Important parameters IIYC

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OBD nuclear dissipation parameter ：

I.I. Gontchar, L.A. Litnevsky, Z. Phys. A 359, 149 (1997)

SPS nuclear dissipation parameter ：

P. Fröbrich, I.I. Gontchar, N.D. Litnevsky, N. Phys. A 556, 281 (1993)

N. Carjan

Important parameters IIIYC

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Coordinate Relationship of Nuclear DissipationCoordinate Relationship of Nuclear Dissipation

MotiveYC

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MCDSM (Driving Potential) IYC

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W. J. Swiatecki, Nucl. Phys. A 574, 233 (1994)

MCDSM (Driving Potential) IIYC

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The Modified Combined Dynamical Statistical Model (MCDSM model)

• Potential V (q) R.W. Hasse, Ann. Phys. 68, 377 (1971)

Y.C. Mao, and B.P. Gu, J. Phys.G 32, 2109 (06)

MCDSM (LDP)YC

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• LDP a (q)

2/ 3 1/ 3( , ) ( ) ( ),v s s k ka q A a A aA B q a A B q= + +

Results and DisscusionsYC

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Y.C. Mao, and B.P. Gu, J. Phys.G 32, 2109 (06)

Pathwise Analysis Method IYC

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(l)(k)(j)

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n pre

n pre

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n pre

(i)(h)(g)

(f)(e)(d)

(c)(b)

TS1 + MCDSM Ign + MCDSM TS2 + MCDSM MD + MCDSM PRA + MCDSM Rei + MCDSM TS + CDSM Ign + CDSM

gs-sd sd-ss gs-ss

(a)

Pathwise Analysis Method IIYC

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191,194,197,200,203191,194,197,200,203AuAu

Pathwise Analysis Method IIIYC

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0

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(a)

0

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SPS Dissipation OBD Dissipation

0

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ngs-ss

nsd-ss

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194Au + CDSM

197Au + CDSM

200Au + CDSM

203Au + CDSM

191Au + MCDSM

194Au + MCDSM

197Au + MCDSM

200Au + MCDSM

203Au + MCDSM

(c)

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Pathwise Analysis Method IV YC

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200Pb

Pathwise Analysis Method VYC

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SummaryYC

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The emission of prescission paritcle decends with increasing coordinate relationship of LDP. In order to ascertain the deformation and temperature relationship of nuclear dissipation, it is necessary to take other parameters into account in the synchronizing and self-consistent way.

The emission of prescission paritcle is controled by the competition between the driving force (from the free energy)and the nuclear damping force (nuclear dissipation) in local deformation section.

Thank You!