首页> 外文学位 >Extracting the asymptotic normalization coefficients in neutron transfer reactions to determine the reaction rates for magnesium-22(proton,gamma)-aluminum-23 and fluorine-17(proton,gamma)-neon-18.

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Extracting the asymptotic normalization coefficients in neutron transfer reactions to determine the reaction rates for magnesium-22(proton,gamma)-aluminum-23 and fluorine-17(proton,gamma)-neon-18.

机译：提取中子转移反应的渐近归一化系数，以确定镁22（质子，γ）-铝23和氟17（质子，γ）-氖的反应速率。

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The nucleosynthesis of the beta+-unstable 18 F and 22Na nuclei in oxygen-neon novae is considered one of the crucial subjects in the field of nuclear astrophysics. They are produced in thermonuclear runaway processes via radiative proton-capture reactions and may be ejected into the stellar medium when the sudden outbursts of the envelope occur. Recent observations with gamma-ray telescopes, however, have not detected those long-lived gamma-ray emitters.;The problem is to study the importance of the rates of the 17 F(p,gamma)18Ne and 22Mg( p,gamma)23Al reactions that may influence the abundances of 18F and 22Na, respectively. To investigate their productions, an indirect technique has been applied to determine these reaction rates at stellar energies through measurements of the asymptotic normalization coefficients (ANCs) in the mirror nuclear systems. The ANCs for 18O and 23Ne are obtained from the neutron transfer reactions 13C(17O, 18O) 12C and 13C(22Ne, 23Ne) 12C at 12 MeV/nucleon, respectively. The ANC of 13C, which represents the other vertex in the transfer reactions, has also been measured to be C2p1/2 = 2.31 +/- 0.08 fm-1.;The differential cross-sections for the reaction 13C( 22Ne, 23Ne)12C because of transitions from the Jpi = 12 - in 13C to the Jpi = 52 + and 12 + states in 23Ne, have been detected. Optical model parameters for use in the DWBA calculations were obtained from measurements of the elastic scatterings 22Ne+13C and 22Ne+ 12C at the same energy. The extracted ANCs in 23Ne are transposed to their corresponding values in 23Al. The astrophysical S-factor S1-22(0) was determined to be 961 +/- 105 eVb. The reaction rate calculated from these results shows that the 22Mg(p,gamma)23Al reaction may reduce the production of 22Na in massive novae M ≈ 1.35 M⊙ .;A similar procedure has been followed in studying the 13C( 17O, 18O)12C reaction. The ANCs related to the Jpi = ( 0+1,2+1,4+ 1,2+2 ) states in 18Ne were determined from their corresponding values in 18O, then used to calculate S 1-17(0) = 2.5 +/- 0.4 keV b. These results show that the reaction rate of 17F(p,gamma )18Ne is dominated by the direct capture to the 2+2 and 2+1 states at astrophysical energies. The calculated reaction rate is considered to be slow, which leads to an increase in the production of 18F in oxygen-neon novae.

机译：氧氖新星中β+不稳定的18 F和22Na核的核合成被认为是核天体物理学领域的关键课题之一。它们是通过辐射质子俘获反应以热核失控过程产生的，并可能在包膜突然爆发时被喷射到恒星介质中。然而，最近用伽马射线望远镜观测到的并没有发现那些寿命长的伽马射线发射器。问题是要研究17 F（p，γ）18Ne和22Mg（p，γ）的发射率的重要性。 23Al反应可能分别影响18F和22Na的丰度。为了研究它们的产生，已应用间接技术通过测量镜面核系统中的渐近归一化系数（ANC）来确定恒星能量下的这些反应速率。 18O和23Ne的ANC分别从中子转移反应13C（17O，18O）12C和13C（22Ne，23Ne）12C以12 MeV /核子获得。代表转移反应中另一个顶点的13C ANC也经测量为C2p1 / 2 = 2.31 +/- 0.08 fm-1 .;反应13C（22Ne，23Ne）12C的微分截面由于从13C中的Jpi = 12-过渡到23Ne中的Jpi = 52 +和12 +状态，已经检测到。 DWBA计算中使用的光学模型参数是通过在相同能量下对弹性散射22Ne + 13C和22Ne + 12C的测量获得的。在23Ne中提取的ANC被转置为其在23A1中的对应值。天体S因子S1-22（0）确定为961 +/- 105 eVb。从这些结果计算出的反应速率表明，22Mg（p，γ）23Al反应可能会减少大质量M＆ap;中新陈代谢的22Na的产生。 1.35 M＆odot;在研究13 C（17 O，18 O）12 C反应中遵循了相似的程序。根据18O中的相应值确定与18Ne中的Jpi =（0 + 1,2 + 1,4 + 1,2 + 2）状态有关的ANC，然后将其用于计算S 1-17（0）= 2.5 + /-0.4 keV的这些结果表明，在天体物理能量下，直接捕获到2 + 2和2 + 1状态决定了17F（p，γ）18Ne的反应速率。计算的反应速率被认为是缓慢的，这导致氧氖新星中18 F的产量增加。

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作者
Al-Abdullah, Tariq Abdalhamed.;
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作者单位

Texas A&M University.;

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授予单位 Texas A&M University.;
学科 Physics Nuclear.;Physics Astronomy and Astrophysics.;Chemistry Nuclear.
学位 Ph.D.
年度 2007
页码 175 p.
总页数 175
原文格式 PDF
正文语种 eng
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专利

1. Asymptotic normalization coefficients from proton transfer reactions and astrophysical S factors for the (CNOC)-C-13(p, gamma)N-14 radiative capture process [J] . Mukhamedzhanov AM., Azhari A., Burjan V., Nuclear Physics, A: Journal Devoted to the Experimental Study of the Fundamental Constituents of Matter and Their Actions . 2003,第0期

机译：（CNOC）-C-13（p，γ）N-14辐射捕获过程的质子传递反应和天体S因子的渐近归一化系数
2. Test of determination of (p, gamma) astrophysical S-factors using the asymptotic normalization coefficients from neutron transfer reactions [J] . Bing G, Zhi-Hong L, Wei-Ping L, Chinese physics letters . 2007,第9期

机译：使用中子转移反应的渐近归一化系数确定（p，γ）天体S因子的测试
3. Test of determination of (p, gamma) astrophysical S-factors using the asymptotic normalization coefficients from neutron transfer reactions [J] . Bing G, Zhi-Hong L, Wei-Ping L, Chinese physics letters . 2007,第9期

机译：使用中子转移反应的渐近归一化系数确定（p，γ）天体S因子的测试
4. Extracting the Asymptotic Normalization Coefficients in Neutron Transfer Reactions to Determine the Astrophysical Reaction Rates for 22Mg(p,)23Al and 17F(p,)18Ne [C] . T. Al.-Abdullah, F. Carstoiu, X. Chen, Carpathian School of Physics . 2008

机译：提取中子转移反应中的渐近标准化系数，以确定22mg（p，）23al和17f（p，）18ne的天体物理反应速率
5. Direct measurement of the sodium-21(proton,gamma) magnesium-22 resonant reaction rate in nova nucleosynthesis. [D] . Bishop, Shawn. 2003

机译：在新星核合成中直接测量钠21（质子，γ）镁22共振反应速率。
6. Nonadiabatic rate constants for proton transfer and proton-coupled electron transfer reactions in solution: Effects of quadratic term in the vibronic coupling expansion [O] . Alexander V. Soudackov, Sharon Hammes-Schiffer -1

机译：溶液中质子转移和质子耦合电子转移反应的非绝热速率常数：二次项在振动耦合扩展中的作用
7. Cross sections of the gamma, proton and gamma, proton neutron reactions in argon-40 [O] . Golden, Stanley Arthur 1960

机译：氩气40中γ，质子和γ，质子中子反应的截面

Extracting the asymptotic normalization coefficients in neutron transfer reactions to determine the reaction rates for magnesium-22(proton,gamma)-aluminum-23 and fluorine-17(proton,gamma)-neon-18.

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