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1.
颜胜权 李志宏 王友宝 K. Nishio H. Maki 苏俊 李云居 I. Nishinaka K. Hirose 韩银录 郭冰 曾晟 连钢 陈永寿 柳卫平 《原子核物理评论》2017,34(3):420-424
95Zr(n,γ)96Zr是稳定燃烧的恒星中合成96Zr的唯一途径,对研究恒星演化和重元素合成具有重要的意义。由于95Zr半衰期为64 d,直接测量95Zr(n,γ)96Zr截面极为困难,因此,本工作采用替代比率法间接测量95Zr(n,γ)96Zr截面。本工作测量了94Zr(18O,16Oγ)96Zr和90Zr(18O,16Oγ)92Zr反应,得到了复合核96Zr*和90Zr*衰变到γ道的几率比,并利用截面已知的91Zr(n,γ)92Zr截面乘以实验所测比率,得到了En=0~8 MeV能区的95Zr(n,γ)96Zr中子俘获截面。95Zr(n, γ)96Zr cross section is important for the study of stellar evolution and heavy elements nucleosynthesis because the reaction is the only way to produce the 96Zr in Asymptotic giant branch stars. The direct measurement of 95Zr(n, γ)96Zr is very difficult due to the short half-life of 95Zr, 64 days. The surrogate ratio method was carried out to measure 95Zr(n, γ)96Zr cross sections. We measured the 94Zr(18O, 16Oγ)96Zr and 90Zr(18O, 16Oγ)92Zr reactions and obtained the γ-decay probability ratio of compound nuclei 96Zr* and 92Zr*. The 95Zr(n, γ)96Zr cross section is determined by the obtained ratio multiplying the known 91Zr(n, γ)92Zr cross section at En=0~8 MeV. 相似文献
2.
The 44Ca(p, γ) reaction was studied for 45 resonances for Ep = 1.6?2.2 MeV. The overall proton energy resolution was 300–350 eV; the γ-rays were detected with both NaI(T1) and Ge(Li) detectors. Partial and total γ-ray widths were measured for each of the fine structure states of the and analogue states at Ep = 1.65 and 2.04 MeV, respectively. The data are examined for correlations between the partial widths (Γp, Γp′, Γγi, Γγtotal) in different channels. The γ-ray intensities are compared with (τ, d) spectroscopic factors. 相似文献
3.
The cross section for the reaction 84Sr(p, p0)84Sr has been measured for proton energies in the range Ep = 4.18?6.73 MeV. Resonance parameters were determined for 15 isobaric analogue resonances. Spectroscopic factors calculated for the analogues by means of the R-matrix theory and the Green function method are compared with Spectroscopic factors determined from the 84Sr(d, p)85Sr reaction. Angular distributions were measured at Ep = 7 and 12 MeV in order to obtain optical model parameters. 相似文献
4.
Lixin Chen Suyang Xu Zhiyuan Zhang Jianguo Wang Minghui Huang Mingming Zhang Long Ma Huabin Yang Chunli Yang Xiaolei Wu Houbing Zhou Zhen Zhao Xinyuan Huang Hao Zhou Xu Zhang Luchong Sun Zongchi Li Zaiguo Gan 《中国物理C(英文版)》2023,47(5):054001-054001-5
The complete fusion reaction of \begin{document}$^{55}$\end{document} ![]()
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Mn + \begin{document}$^{159}$\end{document} ![]()
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Tb was studied on the gas-filled recoil separator SHANS2. Nineteen ER - α\begin{document}$_{1}$\end{document} ![]()
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- α\begin{document}$_{2}$\end{document} ![]()
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decay chains from \begin{document}$^{210}$\end{document} ![]()
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Th produced from the 4n evaporation channel were observed. The α-particle energy and half-life of \begin{document}$^{210}$\end{document} ![]()
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Th were determined as 7922(14) keV and 14(4) ms, respectively. In addition, the decay properties of \begin{document}$E_{\alpha}$\end{document} ![]()
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= 7788(14) keV and \begin{document}$T_{1/2}$\end{document} ![]()
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= 36\begin{document}$^{+15}_{-8}$\end{document} ![]()
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ms were obtained for \begin{document}$^{211}$\end{document} ![]()
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Th. The measured α decay properties of \begin{document}$^{210}$\end{document} ![]()
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Th and \begin{document}$^{211}$\end{document} ![]()
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Th were consistent with literature data. The cross sections were measured to be 0.59\begin{document}$^{+0.25}_{-0.23}$\end{document} ![]()
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nb and 0.19\begin{document}$^{+0.12}_{-0.09}$\end{document} ![]()
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nb for \begin{document}$^{210}$\end{document} ![]()
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Th and \begin{document}$^{211}$\end{document} ![]()
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Th, respectively. The equilibrium charge state of the recoiled nucleus \begin{document}$^{210}$\end{document} ![]()
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Th was determined experimentally. The new data were helpful for estimating the equilibrium charge states of elements 119 and 120, which could be produced via the \begin{document}$^{240}$\end{document} ![]()
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Pu(\begin{document}$^{55}$\end{document} ![]()
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Mn, 3n)\begin{document}$^{292}$\end{document} ![]()
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119 and \begin{document}$^{243}$\end{document} ![]()
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Am(\begin{document}$^{55}$\end{document} ![]()
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Mn, 3n)\begin{document}$^{295}$\end{document} ![]()
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120 reactions, respectively. 相似文献
5.
This paper reports that the experimental excitation functions of reaction (p,n) are measured for ^106pd and ^110pd at proton energy Ep = 6.1 - 7.5 MeV and Ep = 6.0 - 7.7 MeV respectively. The off-resonance excitation functions were compared with calculation values of the statistical model. A new formula used to estimate the peak cross section of isobaric analogue resonance was tested and it was found that calculation values agree reasonably well with the present data within experimental error, which confirms that the excitation strength of isobaric analogue state in (p,n) reaction not only depends on its spin, but also proportionally increases with the projectile proton spatial transmission Tp and the spectroscopic factor S for reaction (d,p) on the same target. 相似文献
6.
We have analyzed the D^0→π^+π^- decay with α_s corrections in quantum chromodynamic (QCD) factorization and with the soft-gluon corrections in the light cone QCD sum rules. The soft-gluon effects are firstly calculated in the decay channel. The results show that once the factorization contributions, the α_s corrections, and the soft-gluon effects are all considered, we can satisfactorily explain the experimental data in the decay channel. 相似文献
7.
8.
Z. Y. Tian Y. L. Ye Z. H. Li C. J. Lin Q. T. Li Y. C. Ge J. L. Lou W. Jiang J. Li Z. H. Yang J. Feng P. J. Li J. Chen Q. Liu H. L. Zang B. Yang Y. Zhang Z. Q. Chen Y. Liu X. H. Sun J. Ma H. M. Jia X. X. Xu L. Yang N. R. Ma L. J. Sun 《中国物理C(英文版)》2016,40(11):111001-111001
A cluster-transfer experiment of 9Be(9Be,14C→α+10Be)α at an incident energy of 45 MeV was carried out in order to investigate the molecular structure in high-lying resonant states in 14C. This reaction is of extremely large Q-value, making it an excellent case to select the reaction mechanism and the final states in outgoing nuclei. The high-lying resonances in 14C are reconstructed for three sets of well discriminated final states in 10Be. The results confirm the previous decay measurements with clearly improved decay-channel selections and also show a new state at 23.5(1) MeV. The resonant states at 22.4(3) and 24.0(3) MeV decay primarily into the typical molecular states at about 6 MeV in 10Be, indicating a well developed cluster structure in these high-lying states in 14C. Further measurements of more states of this kind are suggested. 相似文献
9.
采用蒙特卡罗程序MCNP计算了西安脉冲堆中子代时间。使用MCNP程序模拟了反应堆瞬发中子通量密度衰减,基于忽略缓发中子项的点堆动力学方程计算出中子代时间。在微次临界下,研究了次临界度、源的分布、计数区域等对西安脉冲堆中子代时间计算结果的影响。计算分析表明:采用瞬发中子密度衰减法计算中子代时间时,微次临界度、源分布、计数区域等对计算结果影响都很小;误差产生的主要原因是忽略缓发中子项的点堆动力学方程并不能较好地反应瞬发中子通量密度的衰减规律。 相似文献
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11.
The decay of ^72Ga has been investigated by means of γ-ray spectroscopy. The 72Ga nuclei were produced through the ^71Ga(n, γ)^72Ga reaction. The Compton-suppressed spectrometer and high-purity Ge detectors have been used singly and in coincidence, separately, to study γ-rays in the β-decay of ^72Ga to ^72Ge. Ninety-three events of γ-rays were reported, of which 7 were observed for the first time. A decay scheme of ^72Ga including 4 new levels is proposed which accommodates 87 of these transitions. Spins and parities for new levels are proposed from calculated logft values, modes on the observed decay, and some nuclear reaction experimental results. 相似文献
12.
自发裂变和α衰变是影响超重核稳定性的两个主要因素。为了探索270Ds附近的长寿命的超重核,系统地计算了电荷数在104 ≤ Z ≤ 112范围内的α衰变与自发裂变之间的竞争。采用推广的液滴模型和唯象的解析公式计算了α衰变半衰期。基于包括壳效应和同位旋效应的WKB近似方法估算了相同超重核的自发裂变半衰期,进而预测了未知超重核274-276,279Cn与267-269Ds的衰变模式。The stability of superheavy nuclei (SHN) is controlled mainly by spontaneous fission and α decay processes. To investigate whether long lived SHN could really exist around 270Ds, the competition between α decay and spontaneous fission in the region 104 ≤ Z ≤ 112 are studied systematically. The α decay half-lives are investigated by employing a generalized liquid drop model (GLDM) and phenomenological analytical formula. Calculations of spontaneous fission half-lives for the same SHN are carried out based on the Wenzel-Kramers-Brillouin(WKB) approximation with both the shell effect and the isospin effect included. Decay modes are predicted for the unknown nuclei 274-276,279Cn and 267-269Ds. 相似文献
13.
Susumu Ohya 《Nuclear Physics A》1974,235(2):361-377
The energy levels of 97Ru have been studied through the decay of 31.1 min 97gRh and 44.3 min 97mRh using Ge(Li), Si(Li), Nal, plastic and anthracene detectors in singles and in coincidence experiments. A total of 139 γ-rays were observed. Ninety-eight γ-rays have been placed into the decay schemes involving 38 excited levels in 97Ru. The level energy of 97mRh was determined to be 258.6 keV. The spin and parity of 97gRh and 97mRh are assigned as , respectively. The fraction of decay of the isomer by the isomeric transition was measured with the Si(Li) detector, and αk values were determined for strong transitions. The half-life of the 188.6 keV, state in 97Ru was determined as 0.23 ± 0.02 ns by delayed e-γ coincidence measurements. The nuclear structure of low-lying levels is compared with similar levels in other odd-mass nuclei (N = 53) isotones and Ru isotopes). 相似文献
14.
In this paper we present data on the charged-particle decay of the isoscalar 2+ strength between 10 and 20 MeV excitation energy (Ex) in 24Mg and 40Ca. The isoscalar strength was excited by inelastic scattering of 120MeV α-particles at 14° and 12.5° for 24Mg and 40Ca, respectively. The charged particles originating from the decay were detected in coincidence with the α′ particles at several angles in the scattering plane. Jπ assignments of the decaying states were made on the basis of the angular correlation pattern of the α0 decay to the ground state of 20Ne and 36Ar, respectively, using a DWBA calculation for the m-state population of the decaying state.For 40Ca, about 40% of the E2 EWSR is found to be located in the interval Ex = 13.5 ± 1.5 MeV, which is similar to what has been found from previous inelastic scattering experiments at Ex = 18 ± 2 MeV, but much more than such experiments located in the region Ex = 12–15 MeV. The difference for the region Ex < 16 MeV is due to the fact that from our α0 angular correlation pattern we conclude that virtually no continuum is excited in the (α, α′) process up to Ex = 16 MeV while all previous inelastic hadron scattering experiments assumed such a continuum to be present. The E2 strength distribution for 40Ca thus obtained is very different from what previous theoretical calculations predict. For 24Mg about 30% of the E2 EWSR is present in the interval 12.5 ? Ex ? experiments. 16.5 MeV which again is about twice as much as deduced from previous inelastic scattering The observed branching ratios are compared with calculated ones assuming statistical decay. Reasonable agreement was obtained for 40Ca, but for 24Mg especially the α0-decay branch and to a lesser extent also the p1 one are much stronger than the statistical calculations predict, indicating that especially the α0 decay occurs mainly in a non-statistical way.A similar conclusion can be drawn from the behaviour of the forward-backward asymmetry in the angular correlations of the decay particles as a function of the excitation energy FBA(Ex). For 40Ca, FBA(Ex) for all decay channels increases smoothly on the average once Ex is above a well-defined threshold, which is due to the onset of knock-out processes. For 24Mg, however, the FBA(Ex) for the α0 shows a large fluctuation as a function of Ex, indicating an interference process between semi-direct decay and knock-out processes. 相似文献
15.
Theα-decay of isobaric analogue states (which are forbidden by isospin selection rules) excited in24Mg and28Si through preton capture by23Na atE
p=677 and 739 keV and by27Al atE
p=295, 327 and 405 keV, respectively, have been studied using solid state track detectors. The ratio ofα-decay widths of the two resonance states in24Mg to the state at 1.632 MeV (2+) in20Ne yields the value 0.065 for the mixing parameterε and the value 4.01 keV for the Coulomb matrix element responsible for the isospin mixing in24Mg.
In28Si the measurement of theα-decay widths of the three resonance states resulted in the determination of the proton, gamma and alpha partial widths which
comprise the total width of the resonance states. Limits have been set for the value of the two mixing parameters involved
in this case. Upper limits of 16 and 39 keV have been obtained for the Coulomb matrix elements responsible for the isospin
mixing in28Si. 相似文献
16.
Differential cross-section and analysing-power excitation functions were measured for elastic proton scattering from Ep = 3.6–6.4 MeV at θc.m. = 90°, 115.8°, 129.8° and 155.3°. Differential cross-section angular distributions were measured at 3.56, 3.94, 5.78 and 8.98 MeV and analysing-power angular distributions at 5.78 and 8.98 MeV. Optical-model parameters were deduced from these distributions. Resonance parameters were determined for eight analogue resonances in 71Ga and neutron spectroscopic factors were calculated. These were compared with the results of previous (p, p) cross-section analyses and the results of (d, p) reactions leading to states in 71Zn. 相似文献
17.
The excited states of the 72Ge nucleus were investigated in radioactive decay of 72As. Three new transitions with 1996.58, 2125.59 and 2255.49keV have been found for the first time. One γ-ray with 912.09keV has been placed in the decay scheme for the first time, and the placement of 1938.88, 2116.79, 2785.59, 2833.03, 2950.69 and 3338.00keV γ-rays are confirmed again in the present work. One new level at 2027.72keV excitation energy is proposed. The level scheme was established and for a number of levels spin-parity assignments are suggested on the basis of logft values and γ-branching ratios. 相似文献
18.
S. Mittag D. Pabst L.B. Pikelner W. Pilz R. Tschammer A. Meister D. Seeliger K. Seidel 《Nuclear Physics A》1985,435(1):97-109
Transmission spectra were measured with the time-of-flight technique at the Dubna pulsed reactor for samples of metallic U, UO2, U3O8, and UO3 enriched in 235U, and were compared in the regions of nine low-energy resonances to observe chemically induced shifts. After elimination of contributions caused by different Doppler broadenings, the shifts are interpreted as changes of the mean-square charge radius for nuclei capturing neutrons. The 〈r2〉 of the compound-nucleus states show on average a weak diminution as compared with the ground-state value. 相似文献
19.
E. Arai M. Futakuchi H. Kamada J. Komaki T. Matsuzaki M. Ogawa Y. Oguri 《Nuclear Physics A》1982,378(2):259-272
Using a proton beam with an overall resolution of 300–400 eV (FWHM) spins, parities and partial widths were determined for all resonances observed (99 s-wave, 42 p-wave, 106 d-wave and one g-wave resonances). Differential cross sections for proton elastic scattering from 56Fe were measured at proton energies between 3.1 and 4.2 MeV. Spectroscopic factors and Coulomb displacement energies were extracted for the fragmented analogue resonances which correspond to the , and states in 57Fe. A value of the s-wave proton strength function was deduced. 相似文献
20.
N.P. Balabanov Yu.M. Gledenov Pak Hong Chol Yu.P. Popov V.G. Semenov 《Nuclear Physics A》1976,261(1):35-44
An investigation of the (n, α) reaction on 147Sm and 149Sm isotopes was performed in the energy range from 0 up to 400 eV and to 100 eV, respectively, using a multisectional proportional chamber. Values for the total α-widths or their upper limits were obtained for about 90 resonances. A comparison has been drawn between the obtained average α-widths and those predicted by optical and cluster models. In the case of 149Sm, for resonances with spin 4? the total α-width distribution was observed to be much narrower than expected from statistical theory. We failed to find a correlation between neutron and total α-widths. 相似文献