Angular momentum limitation of cluster emission from the compound nucleus: 16O(16O, α)28Si and 16O(16O, 8Be)24Mg

Excitation functions of the (¹⁶O, α) and (¹⁶O, ⁸Be) compound reactions on ¹⁶O have been measured and compared with Hauser-Feshbach model calculations. Using transmission coefficients for penetration of the real potential barrier in the exit channels we find global agreement, in contrast to systematic deviations obtained with optical-model transmission coefficients.     

Production of fragments withA≧16 in interactions of 6.3 GeV deuterons with Th,Bi, Au,and Ag

Polycarbonate track detector Makrofol, sensitive to fragments withA16 was used to register products of interactions of 6.3 GeV deuterons with Th, Bi, Au, and Ag. Cross sections for the production of events with one, two and three fragments have been determined and their variation as a function of theZ ²/A of the target analyzed. Possible mechanisms were proposed and discussed. Geometric characteristics of binary events were used in order to identify those binary events which resulted from the process of fission. The results were compared with corresponding proton data.We are grateful to Profs. A. M. Baldin and I. N. Semenyuskin for the exposure of the detectors and for measurement of the flux. We are also thankful to the technical staff of our Laboratory for accurate measurements.     

16O(α,γ)20Ne反应的实验研究

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.......     

In memory of V.I. Zaborov (March 16, 1927–August 30, 2004)

Chronicle

In memory of V.I. Zaborov (March 16, 1927–August 30, 2004)     

X-Ray Emission from Zr, Mo, In and Pb Targets Bombarded by Slow Highly Charged Ar^q＋（q = 13, 14, 15, 16） Ions

We study the L x-ray emission from Zr, Mo and In targets and M x-ray emission from Pb target under bombardment of low energy Ar^q (q = 13, 14, 15, 16) ions. The relative x-ray yields were measured in the projectile kinetic energy range 210-360 keV. It is found that the relative x-ray yields from Zr, Mo and Pb targets increase with the increasing projectile kinetic energy for Ar^14 and Ar^16 projectiles and depend on the potential energy of the projectile remarkably.     

CO2同位素分子16O12C16O, 16O12C17O, 16O13C17O配分函数研究

本文主要研究了CO2的三种同位素分子16O12C16O , 16O12C17O ,16O13C17O 70 K~6000 K的总内配分函数 (TIPS)。在总内配分函数的计算中, 转动配分函数的计算采用了McDowell的解析式法, 振动配分函数则采用了简谐振动近似(HOA)获得。最后通过将两配分函数乘积近似计算得出TIPS, 并将其70~3000 K的数据和HITRAN04数据进行了比较, 发现所得结果和数据库符合的较好, 且其误差可以近似看成一条直线。并通过对误差的拟合修订了高温区(3000~6000 K)的计算数据, 给出了在高温下的较为准确的TIPS值。     

在独立α集团模型下对敲出反应16O(p,pα)12C和16O(α,2α)12C的研究

在独立α集团模型下,利用扭曲波冲量近似(DWIA),计算了实验室系下入射能量为101.5MeV的敲出反应16O(p,pα)12C和实验室系下入射能量分别为90MeV和140MeV的敲出反应16O(α,2α)12C.得到的反应截面和谱因子与实验数据基本符合,比用壳模型的结果有了一定的改进,表明独立α集团模型能较好地描述α集团敲出反应的机理.     

16DJL-10型16毫米棱镜补偿式高速摄影机研制成功

自从中国科学院西安光机所于1980年首先研制成功LBS-16A型16mm棱镜补偿式高速摄影机之后,高速摄影战线上又传来喜讯,中国核仪器设备总公司于1983年12月在江苏省苏州市召开鉴定会议,对核工业部二六七厂研制成功的16DJL-10型16毫米棱镜补偿式高速摄影机进行了技术鉴定,与会代表经过严格的测试和审查,一致通过鉴定,并同意推广。     

渐进非对称陀螺分子16O3及同位素16O18O16O的配分函数研究

采用乘积近似法计算了臭氧分子16O3及其同位素16O18O16O在20-6000 K温度范围内的总配分函数。其中转动配分函数用Watson的刚性转子模型,振动配分函数用谐振子模型．总的温度范围被划分为五个温度段。计算的配分函数在这五个温度段分别被拟合到一个温度T的五阶多项式,从而在每个温度段均得到六个拟合系数。由这些拟合系数就可以快速、准确的获得分子在所研究温度范围内任意温度的总配分函数。研究结果为目标特性识别、气动物理的高超声速技术等领域的研究提供了重要的参考信息。     

Inclusive neutron,proton and deuteron energy spectra from stopped π− absorption in 6Li, 9Be, 16O and 27Al

Inclusive energy spectra (E ⩾ 20MeV) of neutrons, protons, and deuterons emitted after stopped π⁻ absorption in ⁶Li, ⁹Be, ¹⁶O and ²⁷Al (neutrons only) were measured. Single-neutron emission rates of the order of 10⁻² and 10⁻³ per stopped pion were obtained for ⁶Li, ⁹Be, ¹⁶O and for ²⁷Al respectively. The experimental data indicate a predominant contribution of two-nucleon absorption mechanism to the neutron and proton spectra for all the studied nuclei, and presence of direct deuterons from cluster-absorption for ⁶Li. Values of R_np are deduced, which are consistent with predictions based on the absorption mechanism by a correlated pair of nucleons with pion rescattering.     

Location of multiparticle-multihole strength in 16N via the 3-particle transfer reaction 13C(α, p)16N at 118 MeV

Differential cross sections were measured for the ¹³C(α, p)¹⁶N reaction at E_α = 118 MeV for an excitation energy range up to 14.5 MeV. Zero-range distorted wave Born approximation (DWBA) calculations were performed using microscopic form factors. Spin-parity assignments are suggested for states at 11.21 MeV (6⁻) and 11.81 MeV (7⁻) on the basis of Bansal-French-Zamick weak coupling calculations and DWBA calculations. Arguments from ¹⁶O(e, e'), ¹⁶O(p, p') and the present experiment are given relating to the location of J^π = 4⁻, T = 1 strength in ¹⁶N.     

The 12C(α, γ)16O cross section at stellar energies

The capture reaction ¹²C(α, γ)¹⁶O has been investigated at E = 0.94 to 2.84 MeV with the use of an intense α beam and implanted ¹²C targets of high isotopic purity. The studies involved NaI(Tl) crystals and, for the first time, germanium detectors. The measurement of absolute cross sections, γ-ray angular distributions and excitation functions is reported. A cross section of 48 pb is found at E = 0.94 MeV. The data provide information on the E1 and E2 capture amplitudes involved in the transition to the ground state as well as to excited states. The S-factor at stellar energies has been determined by means of theoretical fits. The results verify the previous report of a substantial higher S-value compared to the value recommended in 1975. The present uncertainty in the S-value as well as possible improvements are discussed. This S-value is of crucial importance to nuclear astrophysics.     

Resonance states in 16O+16O, 12C+16O, α+16O and α+12C with modified Morse potentials

The resonance states in ¹⁶O+¹⁶O, ¹²C+¹⁶O, α+¹⁶O and α+¹²C are described using modified Morse potential proposed earlier whose success has already been demonstrated in the case of ¹²C+¹²C system. The general validity of such a potential with long range, shallow depth and repulsive soft core determined from the resonance data itself is being examined through the present study of the resonances in the above four systems. In each system, the experimental data of a large number of states have been successfully described with a modified Morse potential. The success points out a common mechanism of the origin of these states, and reaffirms authentically the diatomic-like rotational and vibrational picture of the nuclear molecular resonances proposed previously. The close resemblance between the physics of diatomic molecules and nuclear molecular resonances extending to the level of potential which is Morse type in both the cases — although belong to two different areas of physics — is further strengthened through the present study.      

The 16th Annual SPIE International Conference on Infrared and Millimeter Waves, 26–30 August, 1991 Ecole Polytechnique Federale de Lausanne Lausanne, Switzerland

Conference Announcement

The 16th Annual SPIE International Conference on Infrared and Millimeter Waves, 26–30 August, 1991 Ecole Polytechnique Federale de Lausanne Lausanne, Switzerland     

国际电致发光研讨会(东德,巴德 斯图尔 1983年10月16～20日)

这次专题讨论会仍继续三年前列支(Liege)会议的课题,那次会议的文集已刊于J。Lumin.23,1—236(1981)。本次与会代表57人,其中东德38人,其它国家19人。这些外国来宾包括美国、日本、法国和苏联各2人,英国5人,西柏林,德意志联邦、捷克斯洛伐克、芬兰、匈牙利和波兰各1人。会议安排了12个每次一小时的特邀报告,本届讨论会主席、东柏林电子物理学中心研究所(ZIE)的G.O.Muller博士作了关于会议主题