1、Progress of Experimental Nuclear Astrophysics in CIAE,Wei-ping Liu China Institute of Atomic Energy (CIAE) CCAST symposium on physics of isospin and nuclear phase transition August 19-21, Beijing,Nuclear Astrophysics,From macro to micro Nuclear physics in energy production and element synthesis Pro
2、cess, time scales, environment, isotope abundance Astrophysical model,Some of the great discovery of astrophysics in 20th and 21th century,3K microwave background radiation,1965, experimental support for Big-Bang theory Detection of solar neutrino, 1960, message from solar interior Element distribut
3、ion anomaly in metal star Detection of 26Al g-ray, 1980, direct support of explosive nuclear synthesis, development of g-ray astronomy Detection of SN1987A supernova explosion,1987 Experimental explanation of solar neutrino missing, 2003,Exp,The,Nuclear data,Astro Obs,Astro Model,Exp,The,The interpl
4、ay between nuclear physics and astrophysics,Abundance Estimation,Nuclear physics plays role,RIA white paper 2001,RIKEN proposal,Important NP data,S-factor, focus on NP, down to astrophysics Reaction rates, direct input to network calculation Direct capture, direct reactions Resonance, level scheme,
5、level width, and partial width,Where is reaction and decay data in network calculation,Extra low energies,11C(p,)12N,General idea,Production of RIB ( In-flight method) Measurement of (d,n) or (d,p) angular distribution Fit the distribution by DWBA Get ANC or spec factor Use ANC or spec factor to ded
6、uce (p,g) astrophysical S-factor or (n,g) reaction rate,H. M. Xu, PRL 73(1994)2027,More basics,For peripheral transfer reaction: B(d,n)A,two virtual captures:,B + p A n + p d,two ANCs :,and,known value,can be obtained from,The Cross Section for E1 capture,is the kinetic factor,eeff = eN/A for Proton
7、s -eZ/A for Neutrons,ANC or spec factor,BRIF,Tandem: 15 MV Cyclotron: 100 MeV p, 200 mA,RIBs expected,BIRFII,Inverse kinematics,GIRAFFE,Target,Dipole,Quadrapoles,Reaction,Wien filter,W. Liu, NIMB 204(2003)62,Unstable beams produced,Secondary beams summary,Now, with velocity filter the new beam and b
8、eam purity enhancement: 7Be, purity 99 % 17F, 15O, 13N, purity 90 % 10C, new beam, purity 90 % With the future new beams of 14O and 8B etc by using 3He gas target,15 years of research in CIAE,95 2000 2005,7Be(d,n)8B, CIAE, PRL96, CPL2000,6He(p,n)6Li, CIAE, PLB2002,11C(d,n)12N, CIAE, NP2003,8Li(d,p)9
9、Li, PRC2005,11C(p,g)12N, TRIUMF,17F(d,n)18Ne, CIAE,Physics of 7Be,The astrophysical S factor for the 7Be(p,g)8B reaction at solar energies is a crucial nuclear physics input for the “solar neutrino problem”. It was proposed that the S factor can be indirectly determined through the asymptotic normal
10、ization constant (ANC) extracted from the proton pickup reactions of 7Be, with an accuracy comparable to that from direct radiative capture or Coulomb Dissociation reaction.,Results7Be,W. Liu PRL77(1996)611 NPA 616(1997)131c,Physics of 11C,Proton- and a-capture reactions on proton-rich unstable nucl
11、ei of A13 involved in the hot pp chains are thought to be another alternative way to the 3a process for transforming material from the pp chains to the CNO nuclei in the peculiar astrophysical sites where the temperature and density are high enough so that the capture reaction becomes faster than th
12、e competing decay These linking reactions between the nuclei in the pp chains and the CNO nuclei might be of immense importance for the evolution of massive stars with very low metallicities. One of the key reactions in the hot pp chains is the 11C(p,g)12N which is believed to play an important role
13、 in the evolution of Pop stars.,From (d,n) to (p,g),Results11C,W. Liu, NPA728 (2003)275,Network calculation,N. Shu, Nucl. Phys. A 758 (2005) 419c,E983DRAGON,Wei-ping Liu, E983 Proposal,Physics of 8Li,Inhomogeneous model predict that short-lived isotopes are created which allow for more reaction path
14、ways to the heavier elements Reactions involving short-lived radioactive nucleus 8Li, 7Be and 8B play key role 8Li generating reactions: 7Li(n,g)8Li and 7Li(d,p)8Li， 8Li destroying reactions: 8Li(a,n)11B, 8Li(n,g)9Li, 8Li(d,p)9Li, 8Li(d,t)7Li, 8Li(d,n)9Be, etc. 8Li(a,n)11B and 8Li(n,g)9Li are key of
15、 them 8Li has short half life of 0.83 s, so indirect approach is the only way to get (n,g) rates,APJ429(1994)499,Results8Li,Z. H. Li, W. P. Liu et al., Phys. Rev. C 71, 052801(R) (2005),Some details of calculation 1,In agreement with ANL results, A. H. Wuosmaa et al., PRL94(2005)082502, which is 0.9
16、0+ - 0.13,Some details of calculation 2,1,Fitted by experimental known 6,7Li and 12C (n,g) reactions,Results for (n,g) rate,Z. H. Li, W. P. Liu et al., PHYSICAL REVIEW C 71, 052801(R) (2005),Application to mirror system,Angular distribution 8Li(d,p)9Lig.s. Ecm = 7.8 MeV ANC of 9Li 8Li + n is 1.33 +-
17、0.27 fm-1 Charge symmetry, ANC for 9C8B + p is 1.10 +-0.23 fm-1. S-factor and reaction rate for direct capture in 8B(p,g)9C using the ANC,B. Guo et al., Nucl. Phys., in press,Summary,Summary of experiments,1.33+-0.27,3970+-950,Summary,GIRAFFE, a tandem based one stage unstable beam facility proved t
18、o be effective to produce secondary beams suitable for the study of nuclear astrophysics reactions.Angular distribution measurements of transfer reaction in inverse kinematics, together with DWBA/ANC theoretical approach have been used to study the astrophysical reactions indirectly. The astrophysic
19、al S-factors and/or reaction rates for 7Be(p,g)8B, 11C(p,g)12N, 8Li(n,g)9Li were deduced by using the measurements of 7Be(d,n)8B ,11C(d,n)12N, and 8Li(d,p)9Li reactions at the energies of astrophysical interest.,Research Team and support,Bing Guo,Gang Lian,Weiping Liu, ,Xixiang Bai,Baoxiang Wang,Sheng Zeng,Yun Lu,Zhihong Li,Shengquan Yan,Yongshou Chen Nengchuan Shu Kaisu Wu,Youbao Wang,Zhanwen Ma,Xiaodong Tang,NAO, U of Tokyo Toshitaka Kajino,CIAE,Zhanwen Ma,Research project supported by Ministry of science and technology, by National science foundation of China.,
