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1.
用考虑了角动量守恒的BUU模型计算了20MeV≤E/u≤180MeV能区16O+197Au系统的反应线性动量转移(LMT)及余核角动量,着重讨论了反应线性动量转移及余核角动量对反应碰撞参量、入射能E/u的依赖关系,比较了计算LMT与Viola系统性给出的结果间的偏差.计算结果揭示了当E/u≥90MeV时,余核角动量对E/u增长出现的饱和现象,主要来源于靶核对弹核捕获能力的持续丢失.  相似文献   

2.
本文通过对J/ψ辐射衰变到K+K-πO和终态中iota能区的振幅分析,发现iota峰下有一个0-+共振态(M=1467±3MeV,=89±6MeV)和两个1++共振态(M=1435±3MeV,=59±5MeV;M=1497±2MeV,=44±7MeV),分别对应于η(1440),f1(1420)和f1(1510).  相似文献   

3.
比较了铜掺杂钾钠铌酸锶钡(Cu∶KNSBN)和钾钠铌酸锶钡(KNSBN)两样品的晶格振动和d-d电子跃迁谱,对于拉曼(Raman)谱,A1(z)对称类的差别较小,E(xy)对称类的差别最大;对于红外反射谱,两对称类的均差别较大,认为Cu2+部分填充了晶格A位和C位,可见光范围内,d-d电子跃迁谱表明Cu2+在晶体中形成两个深能级2.50eV和2.64eV。  相似文献   

4.
报道30MeV/u40Ar+159Tb反应中碎片碎片关联函数的实验结果.利用三体弹道模型从关联函数提取了中等质量碎片发射时间.中等质量碎片的平均发射时间随碎片能量而变化,从低能时的约500fm/c下降至高能时的约100fm/c.中等质量碎片发射时间随束流能量的升高而下降,表明随着束流能量的升高中等质量碎片发射机制逐渐从相继两体衰变向多重碎裂发射过渡.对于40Ar+159Tb反应,此过渡能区在35—45MeV/u之间  相似文献   

5.
夏海瑞  王凯旋 《光学学报》1996,16(10):510-1515
比较了铜掺杂钾钠铌酸锶钡和钾钠铌酸锶钡两样品的晶格振动和d-d电子跃迁谱,对于拉曼谱,A1(z)对称类的差别较小,E(xy)对称类的差别最大;对于红外反射谱,两对称类的均差别较大,认为Cu^2+部分填充了晶格A位和C位,可见光范围内,d-d电子跃迁谱表明Cu^2+在晶体中形成两个深能级2.5eV和2.64eV。  相似文献   

6.
同位旋相关的Boltzmann—Langevin方程及新核素^19Na产?…   总被引:1,自引:1,他引:0  
介绍了一种同位旋相关的输运方程,研究了在入射能量为28.7和60.0MeV/u时^12C+^12C的反应,对模型进行检验,发现计算结果较好地符合实验结果,说明了方程的可靠性,利用该模型研究了在入射能量为28.7MeV/u下反应系统^17-20,22Ne+^12C中核素^19Na的产生截面,发现缺中子核引起的反映,具有更大^19Na的产生截面,为新核素的探测找到了理论依据。  相似文献   

7.
25MeV/u~(40)Ar ~(93)Nb反应中热核的激发能和核温度   总被引:1,自引:0,他引:1  
利用半导体望远镜探测器和PPAC对25MeV/u40Ar+93Nb反应中的带电粒子和余核进行了关联测量,对所得α粒子能谱用三源模型进行了拟合,并由余核飞行时间和粒子多重性得到热核激发能.通过对温度的修正,发现在本实验中有激发能E*/A为4.3MeV,温度Tinit为6.9MeV的热核形成。通过与其它实验结果的对比可以看出核物质在轻系统和重系统中行为的差异。  相似文献   

8.
在夸克味动力学的计算中,除包含u、d、s夸克及其反夸克外,还涉及粲夸克及其反夸克(cc),采用包含夸克味动力学效应的相对论性流体力学模型,计算了碰撞能量为200GeV/u的238U+238U核碰撞时形成的膨胀QGP及其在相变过程中发射的双轻子谱,轻子对的质量范围M≤4GeV/c2.计算结果与CERNSPS的实验测量数据进行了定性的比较和分析,得到初步的结论:由于夸克碎块和味动力学效应,J/ψ→μ++μ-峰值被降低,导致低质量区(阈至1.35GeV/c2)谱的提高.  相似文献   

9.
利用束箔技术研究由重离子加速器提供的47MeV能量的Ne离子,穿过厚度为39μg/cm^2,的碳箔而产生高离化态类H(NeX)类He(NeⅨ)离子激发谱的情况。  相似文献   

10.
高离化态氖的类H、类He离子激发光谱的研究   总被引:1,自引:0,他引:1  
利用束箔技术研究由重离子加速器提供的47MeV能量的Ne离子,穿过厚度为39μg/cm2的碳箔而产生高离化态类H(NeX)、类He(NeⅨ)离子激发谱的情况。  相似文献   

11.
16O(α,γ)20Ne反应的实验研究   总被引:1,自引:0,他引:1  
讨论了目前16O(α ,γ) 2 0 Ne反应的实验研究工作 ,并对2 0 Na β+—→2 0 N →16O +α的β+ 缓发衰变α能谱的相对强度值同文献进行了比较 ,讨论了低能激发能级、共振强度及其对共振截面的贡献、S因子的理论研究.The experimental investigations of 16 O(α,γ) 20 Ne reaction is reviewed. The energy spectrum of β + delay α decay were measured through the 20 Naβ +-→ 20 Ne *→ 16 O+α process, and the relative densities of α decays are compared with the reference s results. The low excitation energy levels, resonance strength and its contribution to the resonance crosses section are also discussed. Finally, we have calculated the reaction rate of the direct capture reaction.......  相似文献   

12.
Strongly damped components have been studied in relatively light heavy ion reaction systems;20Ne(E lab=93, 120 and 146MeV)+50Cr,20Ne(E lab=146MeV)+54Cr and20Ne(E lab=146MeV)+92Mo,100Mo. The kinetic energy, angular and charge distributions have been observed for those products. The yields of symmetric-mass-splitting products for20Ne+50Cr were found about three times larger than those for20Ne+54Cr. There was also observed a similar difference in the cross sections of the symmetric-mass-splitting products between20Ne+92Mo and20Ne+100Mo reactions. In order to explain the bombarding energy dependence of the cross sections of symmetric-mass-splitting products by the transport theory, it was found necessary to assume that the mean life of the composite nucleus was dependent on the bombarding energy. However, the target isotope dependence of the cross sections could not be explained by such an assumption. They could be partly explained by fission calculations.  相似文献   

13.
Inclusive cross sections of intermediate mass fragments (6Z16) have been measured in 20Ne induced reactions on silver and gold targets at 20, 30, 40, 50 and 60 MeV/u incident energies. Whereas the production yields remain approximately constant for the Ne+Ag system, they increase by a factor of two for the Ne+Au system over the same bombarding energy range. These results are discussed in the framework of two fragmentation models.  相似文献   

14.
The peripheral collision mechanisms have been systemic ally studied via the Boltzmann-Uehling-Uhlenbeck theory in the Fermi domain for 20Ne+20Ne collision system.The characters of energy dependence and the intermediate mass fragment production in the process of incomplete deep inelastic collision were discussed.  相似文献   

15.
Light and projectile-like fragments as well as fission fragments have been observed from the 20Ne + 197Au system at 150, 220, 290 and 400 MeV beam energy. Inclusive cross sections are given, and characteristic parameters like the centroids and the widths of momentum, Z- and A-distributions were derived. For comparison, some results of measurements on the 22Ne + 197Au and 20, 22Ne + 58Ni systems are included. The qualitative behaviour of the cross sections and the derived parameters show that with increasing bombarding energy the incomplete-fusion mechanism (massive transfer) and the sequential decay of projectile transfer residues (sequential break-up) appear in addition to the complete-fusion and ordinary transfer reactions predominant at the lowest bombarding energies. Other mechanisms do not contribute significantly in the energy range up to 20 MeVnucleon.  相似文献   

16.
The vector correlations between products and reagents for the reactions Ne+H + 2 , Ne+D + 2 , and Ne+T + 2 are calculated by means of the quasi-classical trajectory method on a new potential energy surface constructed by Lü et al. [J. Chem. Phys. 2010 132, 014303]. The polarization-dependent differential cross-sections (2π/σ)(dσ 00 /dω t ), (2π/σ)(dσ 20 /dω t ), (2π/σ)(dσ 22+ /dω t ), and (2π/σ)(dσ 21 /dω t ), and the distributions of P (θ r ), P (φ r ), and P (θ r ,φ r ) are calculated. The isotopic effect, which is associated with the difference in mass factor among the three reactions, is revealed.  相似文献   

17.
The20Ne + U reactions are investigated at 290 MeV bombarding energy. The linear momentum transfer and excitation energy are deduced eventwise from the respective measurements of the folding angle between correlated fission fragments and the neutron multiplicity. A simple incomplete fusion picture is shown to essentially account for the data. The sensitivity of the two measurements in order to infer the violence of a collision is discussed in details.  相似文献   

18.
Taking the relative distanceR and the deformationδ of each nucleus as the collective variables, we solve the two dimensional coupled dynamical equations of motion with friction in the framework of the linear response theory. In solving the equations of motion, we approximately replace the inertia tensor with the hydrodynamical one and use the modified liquid-drop one as the collective potential energy. As the frictional coefficients we use the microscopically calculated ones in the previous paper. The calculation is done for the reaction of28Si+20Ne, in which the incident energy of20Ne is 120 MeV. Results show that our microscopically calculated friction gives the large value of energy dissipation which amounts to the “completely damped” collision. Besides it, growths of the oblate deformation in the entrance channel and the prolate deformation in the exit channel are clearly seen. They give a large influence on the time development of the energy dissipation. We compare our calculated results with the experimental data for the reactions of 120 MeV20Ne with27Al. The agreement between them is found to be reasonably good.  相似文献   

19.
在多源理想气体模型的框架内, 用一个关于末态粒子多重数分布的统一描述, 研究了低能重离子诱导反应中轻带电粒子和蒸发剩余物的能谱。 在同一个激发的复合核中, 每个源对带电粒子和蒸发剩余物均贡献一个指数分布的能谱。 计算结果与158, 170, 180 和 200 MeV 20Ne+12C 反应中, 轻带电粒子和蒸发剩余物能谱的实验结果符合。  相似文献   

20.
叙述了对Glauber模型中的透射系数进行半经验的能量修正,并利用该修正模型计算了12—14C,6Li,7Be,8B+12C和6Li,7Be,8B+9Be以及20Ne+12C,12C+27Al等系统的激发函数(能区范围10—1000MeV/u),经与实验值比较,能量修正的Glauber理论计算值能够很好地描述中能条件下的反应总截面实验测量值.  相似文献   

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