35MeV/u~(40)Ar+~(197)Au反应中热核的统计发射研究

利用硅半导体＋ＣｓＩ（Ｔ１）闪烁体望远镜测量３５ＭｅＶ／ｕ４０Ａｒ＋１９７Ａｕ中发射的轻带电粒子，用能谱斜率方法和双同位素产额比方法提取了核温度参量．研究了热核发射过程中的统计发射规律．

30MeV/u~(40)Ar+~(115)In反应中的IMF能谱

测量了 3 0MeV/u40 Ar束流轰击115 In反应靶时出射的中等质量碎片(IMF)的能谱 .通过比较在不同出射角度发射的同一种IMF的能谱 ,得到了IMF的发射机制随出射角的演化关系 .在假定运动源速度和出射离子库仑位垒不随出射角变化的条件下 ,通过改变发射源的强度和核温度参量完成了对实验测得能谱的运动源拟合 ,并详细讨论了 3个发射源所占份额和源强随出射角的演化关系 .

25MeV/u~(40)Ar+~(115)In反应中前中角区碎片发射研究

从 2 5MeV/u4 0 Ar+115In反应前中角区出射碎片的能谱、角分布和Z电荷分布出发 ,讨论了碎片发射机制随出射角和核电荷数Z的渐进变化 ;用改进的量子分子动力学 (MQMD)模型研究了碎片角分布及Z电荷分布 ,理论计算和实验值整体上符合较好 ,但在前角区MQMD模型低估了碎片的产额 ,在中角区对于Z接近弹核的碎片 ,理论计算比实验值偏高 ;碎片产物的角分布及Z电荷分布还与统计模型GEMINI进行了比较 ,发现在前角区平衡蒸发的成分所占比例很小 ,中角区所占的比例有所增加 ,但仍然是较小的比例 .随着碎片核电荷数Z的减小 ,平衡核的蒸发成分逐渐减少 ,非平衡的中速成分逐渐占主导地位

30 MeV/u~(40)Ar+~(nat)Ag反应中类弹碎片发射的时-空演化

报道了 ３０ＭｅＶ／ ｕ(４０)Ａｒ＋(ｎａｔ)Ａｇ反应中中等质量碎片（ＩＭＦ）发射时间（τ）随发射源空间大小的演化规律，并对类弹碎片的发射时空进行了讨论．结果表明，ＩＭＦ的发射时标与中等质量碎片关联函数以及发射源的核物质密度（ρ）有关，而与发射源的质量数的关系不大．对于能量较高的类弹碎片来说，在较小的核物质密度下提取的发射时间也较小，因此，在正常核物质密度参数下提取出的发射时间值可作为碎片实际发射时间的上限值．中速碎片的发射时间随密度大小的变化非常缓慢，提取出的发射时间值即可作为实际的发射时间。

25MeV/u ~(40)Ar+~(115)In,~(58)Ni,~(27)Al反应中前中角区碎片角分布和元素Z分布

测量了 ２５ＭｅＶ／ｕ４０　Ａｒ＋１１５　Ｉｎ，５８　Ｎｉ，２７　Ａ１反应前中角区出射碎片的角分布和 元素 Ｚ分布．用改进的量子分子动力学（ＭＱＭＤ）模型研究了碎片的角分布和 Ｚ 分布．理论计算值和实验值整体上符合得很好，但在前角区，ＭＱＭＤ模型低估 了碎片的产额，在中角区对于Ｚ接近弹核的碎片，理论计算值比实验值偏高．碎 片产物的角分布和Ｚ分布还与统计蒸发模型ＧＥＭＩＮＩ进行了比较，结果表明，在 前角区平衡蒸发成份所占的比例很小，中角区所占的比例有所增加，但仍然是较 小的比例．同时发现平衡蒸发成份随着出射碎片核电荷数Ｚ的减小而逐渐减 少．

Size modification of Au nanoparticles induced by slow highly charged ions Ar-40(q+) irradiation

Size modification of Au nanoparticles (NPs), deposited on the Au-thick film surface and irradiated by slow highly charged ions (SHCI) 40Arq+ (3 6 q 6 12) with fixed low dose of 4.3 1011 ions/cm2 and various energy ranging from 74.64 to 290.64 keV at room temperature (293.15 K), was investigated by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The effect of projectile kinetic energy on the modified size of NPs was explored by an appropriate choice of the fixed process parameters such as ion flux, irradiation temperature, incident angle, irradiation time, etc. The morphological changes of NPs were interpreted by models involving collisional mixing, Ostwald ripening (OR) and inverse Ostwald ripening (IOR) of spherical NPs on a substrate. A critical kinetic energy as well as a critical potential energy of the projectile in the Au NPs size modification process were observed.

Near infrared lights emission of Ar-40(16+) impacting on metal surfaces

The highly charged ion Ar-40(16+) with the velocity (kinetic energy E (K)=150 keV, velocity V=8.5x10(5) m/s) smaller than Bohr velocity (V (Bohr)=2.9x10(6) m/s) was found to hove impacts on the surfaces of metals Ni, Mo, Au and Al, and the Ar atomic infrared light lines and X-rays spectra were simultaneously measured. The experimental results show that the highly charged ion that captures electrons is neutralized, and the multiply-excited hollow atom forms. The hollow atom cascade decay radiates lights from infrared to X-ray spectrum. The intensity of infrared lights shows that the metallic work functions play an important role in the neutralization process of highly charged ions during their interaction with metallic surfaces, which verifies the classical over-the-barrier model.

X-ray spectra induced in highly charged Ar-40(q+) interacting with Au surface

By use of optical spectrum technology, the spectra of X-ray induced by highly charged Ar-40(q+) ions interacting with Au surface have been studied. The results show that the argon K alpha X-ray were emitted from the hollow atoms formed below the surface. There is a process of multi-electron exciting in neutralization of the Ar16+ ion, with electronic configuration 1s(2) in its ground state below the solid surface. The yield of the projectile K alpha X-ray is related to its initial electronic configuration, and the yield of the target X-ray is related to the projectile kinetic energy.

低速~(40)Ar~(17+)离子入射金属Be表面发射的近红外光谱线和X射线谱；Infrared Light and X-ray Emissions of ~(40)Ar~(17+) Impacting on Be Surface ；

用速度不同的(动能EK=272和357keV,速度v=1.14×106和1.72×106m/s)的高电荷态离子40Ar17+分别入射金属Be表面,同时测量这种相互作用过程中产生的近红外光谱线和X射线谱。实验结果表明,在低速范围内(速度小于玻尔速度vBohr=2.19×106m/s),速度较小的40Ar17+离子在到达金属的表面临界距离Rc到进入表面(2—3原子层)的进程中,形成了较多的高激发态Ar原子,其退激辐射较强的光谱线,进而验证了经典过垒模型。

Rotation alignment in neutron-rich Cr isotopes: A probe of deformed single-particle levels across N=40

Recent experiments have reached the neutron-rich Cr isotope with N = 40 and confirmed enhanced collectivity near this subshell. The current data focus on low-spin spectroscopy only, with little information on the states where high-j particles align their spins with the system rotation. By applying the projected shell model, we show that rotation alignment occurs in neutron-rich even-even Cr nuclei as early as spin 8 (h) over bar h and, owing to shell filling, the aligning particles differ in different isotopes. It is suggested that observation of irregularities in moments of inertia is a direct probe of the deformed single-particle scheme in this exotic mass region.

PROJECTILE FRAGMENTATION OF Ar-36,Ar-40 INDUCED REACTIONS

Fragment yields for Z >= 5 from projectile fragmentation using primary beams of Ar-36,Ar-40 at 50 MeV/nucleon on Ni-64 target have been measured in RIBLL fragment separator. We compare the fragment cross sections with the predictions of the empirical EPAX parametrization of fragmentation cross-sections and Statistical Abration-Ablation model (SAA) by considering the RIBLL separator transmission rate. Isotope yield ratios between these two reactions were calculated and isoscaling parameters alpha and beta are extracted, their dependences on fragment atomic number Z and neutron number N were presented.

25MeV/A~(40)Ar+~(115)In反应中轻粒子发射研究及大面积位置灵敏闪烁探测器的研制

论文分为两个部分。第一部分：研究在25MeV/u ~(40)Ar+~(115)In反应中轻粒子发射机制。实验中，利用研制的轻粒子探测器测量了发射的P、#alpha#能谱。用三源模型拟合了轻粒子能谱，所提取的参数与费米气体模型的计算结果进行比较，分析了发射源形成和衰变的一些特点。第二部分：研制一种大面积幅度、时间、位置灵敏闪烁探测器。它是HIRFL上建成的第一阶段放射性核束物理实验终端的主要设备之一，在首次放射性核束调试中收到良好的效果。本文的目的是用经典理论研究了热核形成及衰变的一些性质，在即将开展的放射性核束物理研究中， 利用研制的大型探测器对经典理论普适性进行检验

25MeV/u~(40)Ar~(15+)+~(209)Bi反应的裂变研究

本文首先回顾了重离子物理学的发展简史，并介绍了当前的一些关于重离子反应的理论方法，同时对于现在核物理的研究热点，热核的特性进行了概括性的叙述．由于裂变是作者工作的重点，因此在文章中，对裂变反应的理论也进行了介绍．为了能够清楚全面的说明我们的工作，本文对于实验装置和探测器也给出了详细的描述．最后，文章对25 MeVu Ar+Bi反应中的裂变进行了讨论．在这些讨论中，我们分析了反应中与裂变相关的数据，得到了碎片的质量，动能分布。同时运用与碎片相关联的4He粒子能谱提取了核温度和裂前裂后的4He粒子多重性，并利用这一数据计算了不同初始激发能下的裂点激发能和裂变时标.

30MeV/u~(40)Ar+~(nat)Ag反应中中等质量碎片的发射机制及其发射时间测量

中等质量碎片（IMF）的发射是中能重离子碰撞的一大特点，且随着轰击能量的升高其产额迅速增加。通过测量30MeV/u 40Ar+natAg反应中出射的中等质量碎片，研究了高激发热核的发射机制、发射时标和时空演化规律。 对反应中发射碎片能谱的运动源拟合表明，前角区（11°—22°）中等质量碎片（IMF）来自于三种成分：类靶源、类弹源和中速源成分，其中类弹和中速成分占主导，关联测量的IMF能谱拟合得到，一个来自于类弹源而另一个来自于中速源成分的事件占有相当大的比例。 利用小相对角度内的两碎片关联测量，研究高激发核衰变中中等质量碎片的发射时标和寿命。IMF发射时间随能量的变化很大，从低能碎片的250 fm/c到高能粒子的100 fm/c，表明在此能量下，反应中出射的IMF主要来自于相继两体衰变。通过与其它实验的比较可知，随着束流能量的升高，IMF发射时间由相继两体衰变向多重碎裂过渡。 IMF时空演化研究表明，发射空间的大小对IMF关联函数的影响主要来自于发射源的核物质密度而几乎不依赖于发射源的质量数。