12C6+离子束辐照对小麦种子萌发、幼苗生长及存活的影响

采用12C6+离子束对小麦(Triticum aestivum L)种子进行不同剂量(0、10、20、30、60、120、150和200 Gy)辐照处理,考察种子萌发率、幼苗根长及株高、有丝分裂活动及存活率等生物学特性。结果表明:试验剂量范围内,大多数种子能够正常萌发;低剂量(10 Gy和20 Gy)辐照对幼苗生长具有促进作用,而高剂量辐照则表现出明显的抑制作用;根的生长与分生组织细胞有丝分裂指数密切相关,低剂量时有丝分裂指数略有增加,而高剂量则相反,分裂细胞被选择性阻滞在中期和后期。存活率曲线呈"抛物线"状,半致死剂量(LD50)为55Gy。     

氢氦离子注入机的研制

本文介绍了正研制的氢氦离子注入机的结构和各部分的主要性能指标。它的最高能量为200 keV,可按一定比例同时用氢氦两种离子进行注入实验。该机经调试,各项主要指标已达设计要求,工作稳定可靠。     

The internal conversion coefficients of the 2+–0+, E2 nuclear transitions in even-even nuclei

Measured values of the internal conversion coefficients of 39 E2 (2⁺–0⁺) transitions in even-even nuclei are listed and averaged in most of the cases where there is more than one result. Comparison with values calculated without interpolation by Band, Listengarten, and Trzhaskovskaya shows only fair agreement but no consistent clustering above or below the theoretical expectations. In 13 out of the 39 cases the experimental error bar does not include the theoretical value. Of the experimental values 21 are greater and 18 less than the calculated results.     

Sputtering of materials by H+, D+, T+ and He+ Ions

The sputtering yields of various materials by H⁺, D⁺, T⁺, He⁺ ions were calculated using the theoretical dependence of sputtering yields on energy and ion mass and taking into account experimental sputtering yield values, whenever available, as measured for H⁺, D⁺, T⁺, He⁺ ions.     

石墨中~(36)Cl分析的溶样技术

在反应堆退役过程中,为了使放射性废物最小化,需对石墨中的~(36)Cl进行分析。采用浓硫酸、浓硝酸和高锰酸钾的混合溶液溶解石墨样品,建立了石墨的溶样方法。该溶样方法对~(36)Cl的化学回收率大于89.38%。     

Auger electron spectra in 5.5 MeV/amu Neq+ and Arq+ ion impact on Ne

A study of Ne K Auger spectra induced by 5.5 $\text{MeV}\text{amu}$ Ne³⁺ Ne¹⁰⁺ Ar⁶⁺ and Ar¹⁷⁺ heavy ions on Ne is presented. Some average quantities (the centroid energy of KLL Auger spectra, the average number of L vacancies produced simultaneously with the K vacancy, the effective charge of the projectile in the actual process, the satellite to total intensity ratio) characterising the KLⁿ ionization process have been extracted from these spectra. Relative K-shell ionization cross sections and KLM to KLL cross section ratios have been evaluated. The deduced experimental Z_eff values have been compared with the results of PWBA and BEA calculations. A simple model calculation is made in an attempt to interpret the variation of the probability for the ejection of an L-shell electron (p_L) as a function of $\text{Z}{}_{\mathrm{eff}}\text{v}{}_{\mathrm{p}}$. Some statements regarding individual lines and groups in the Auger spectra are made.     

He+ ion energy loss parameter in thin films of UO2

The stopping cross sections of He⁺ ions in vacuum evaporated films of UO₂ have been measured at incident energies from 0.3 to 2.0 MeV. A procedure has been described for obtaining true stopping cross sections by using thin films having various thicknesses. The energy loss parameter of He⁺ ions was determined using slopes at the origin in relative energy loss vs. thickness curves.     

Adiabatic relativistic rotation-vibration energy levels for HD+, HT+, and DT+

Rotation-vibration energies calculated at the adiabatic level of approximation with the inclusion of relativistic corrections in the potential energy curve are tabulated for HD⁺, HT⁺, and DT⁺ for 0 ≤ v ≤ 8 and 0 ≤ J ≤ 8.     

Observation of a partially-ordered void lattice in aluminium irradiated with 400 keV Al+ ions

Transmission electron microscopy observations of voids formed in aluminium during irradiation at 50°C and 75°C with 400 keV Al⁺ ions, have shown that partially-ordered void arrays are often present. These arrays occur in high-purity annealed aluminium, which has been implanted with 10^?4 atom/atom helium before ion irradiation. The void concentration is found to be $\text{～3 × 10}{}^{16}\text{/ cm}{}^3$, and the void lattice parameter ～ 700 Å. The ratio of void lattice parameter to void radius is ～ 12. Ordered void lattices have been observed frequently in irradiated body-centred cubic metals but the only previous observation for a face-centred cubic metal was in nickel. Theoretical predictions of void lattices in metals are discussed and related to the observations reported herein.     

Some characteristics of the crystalline-amorphous threshold pointof 31P+ ion-implanted silicon substrates

During ion implantation a stage can be reached in which a continuous layer within the implanted crystal changes into amorphous material. The change begins when the implanted dose attains a certain threshold value (D_T). In-situ reflectivity (R) versus dose (D) measurements, made during the implantation of ³¹P⁺ into Si single crystal substrates showing that both D_T and the work (W_oT) required to induce the threshold conditions within the implanted crystal increase with the implantation energy are reported. It is also shown that the change in reflectivity ΔR_i, which occurs in the dose range that contains D_T, is a function of E and peaks at 140 keV, the energy at which the damaged layer becomes buried. The ratio D_A/D_T is found to be a decreasing function of E     

用聚酰胺树脂从~(99)Mo中提取~(99)Tc~m

固相分离材料是色层法从低比活度~(99)Mo料液中分离医用同位素~(99)Tc~m的关键。采用静态吸附和动态吸附淋洗实验,研究了聚酰胺树脂从~(99)Mo中吸附分离其衰变子体~(99)Tc~m的工艺,评价了其性能。结果表明:在NaOH浓度为3mol/L的钼酸钠溶液中,聚酰胺树脂能够在10s内选择性地吸附高锝酸根离子,并具有3.85mg/g的饱和吸附容量。2.0g装柱量的聚酰胺色层柱的漏穿体积约为70 mL,可用25 mL 3 mol/L NaOH溶液洗涤柱上残留的钼酸根离子,最后20mL水即可将吸附在聚酰胺色层柱上的锝淋洗下来。本研究为开发基于色层法的全自动~(99)Mo/~(99)Tc~m发生器装置提供了一种新型钼锝固相分离材料,其提取锝的淋洗效率为98%,洗脱液中钼的残留为0.6mg/L。     

226Ra irradiation to produce 225Ac and 213Bi in an accelerator-driven system reactor

This study aims to produce ²²⁹Th using an innovative nuclear reactor concept,i.e.,accelerator-driven system(ADS)reactor.Herein,we investigated the feasibility of producing ²²⁹Th from neutron transmutation of ²²⁶Ra to expand the availability of ²²⁵Ac and ²¹³Bi in a simple model of ADS reactor.ADS reactor comprises two zones,i.e.,an inner zone with a fast neutron spectrum and outer zone with thermal neutron spectrum,which is a subcritical core...     

The Elliptic Flow of Multi-Strange Hadrons in[SNN]1/2= 200 GeV Au + Au Collisions at STAR

Azimuthal anisotropy, especially for the multi-strange hadrons, is expected to be sensitive to the dynamical evolution in the early stage of high energy nuclear collisions. In this paper we present the latest results of multi-strange hadron elliptic flow in Au + Au collisions at[S_NN]^1/2= 200 GeV from the STAR experiment at RHIC. The number-of-quark scaling is evidenced with φ（s） and （sss） with highly statistical data, which shows strange quark collectivity at RHIC. The ν2 of φ meson is found to be consistent with that of proton within statistical error bars at p T<1 GeV/c.     

用活性碳纤维从~(99)Mo中提取~(99)Tc~m

使用色层法从有载体~(99)Mo料液中提取医用同位素~(99)Tc~m是应对当前裂变~(99)Mo供应危机的新途径。本研究采用静态吸附实验和动态吸附淋洗实验,研究了利用活性碳纤维从~(99)Mo中吸附分离其衰变子体~(99)Tc~m的工艺和性能。结果表明:活性碳纤维可以在3mol/L NaOH体系的钼酸钠溶液中选择性吸附高锝酸根离子,静态吸附平衡时间约500s,吸附过程符合准二级动力学模型,饱和吸附容量为32.47mg/g。在动态吸附淋洗实验中,1.0g装柱量的活性碳纤维色层柱的漏穿体积为70mL,使用40mL水即可将活性碳纤维色层柱上吸附的锝淋洗下来。本实验结果表明,不使用有机溶剂即能用活性碳纤维色层柱完成钼和锝分离,锝的淋洗效率为98%,洗脱液中钼的残留为3.5mg/L。     

Electron impact ionization of N4+ and N5+

A new crossed beams apparatus for measuring absolute electron impact ionization cross-sections of multiply charged ions is described. First measurements are also reported which deal with N⁴⁺ and N⁵⁺. The results are in good agreements with those previously obtained by the Oak Ridge group. For N⁵⁺ a non-negligible signal is observed below the ground state ionization threshold. It is attributed to the presence of ions in metastable states. From the semi-empirical Lotz formula, the population of ions in those states is estimated to be approximately 3%.     

电动势法研究HAN与Fe3+氧化还原反应动力学

采用电动势法研究了硝酸体系中硝酸羟胺(HAN)还原Fe3+离子的反应动力学,得到了动力学表观速率方程-dc(Fe3+)/dt=kc0.62(HAN)c-2.80(H+)c(Fe3+)c-0.85(Fe2+);当温度为50℃、离子强度I=1.0mol/L时,表观速率常数k=(2.9±0.1)×10-6(mol/L)3.02/s,反应表观活化能Ea=(125±3)kJ/mol。硝酸根的存在对反应起到抑制作用,离子强度的增大对反应有促进作用。     

Populations of np terms in deuterium atoms emergent from carbon foils bombarded with D+, D2+ and D3+ ions

We have measured relative beam-foil populations of 2p, 3p, and 4p terms in D⁰ as a function of the projectile energy $\text{(20 ?}\text{E}\text{M}\text{? 500}\text{keV}\text{amu}\text{)}$ for D⁺, D₂⁺, and D₃⁺ ions impinging on carbon foils of various thicknesses (? 2–20 $\text{μg}\text{cm}{}^2$).With D⁺ projectiles, the np populations reach their equilibrium values even in the thinnest foils used. We compare the dependence on energy of these populations to the equilibrium neutral fraction variation for hydrogen (deuterium) beams emerging from a carbon foil and deduce some information concerning beam-foil populations.When molecular projectiles pass through very thin foils, well known molecular effects appear which depend on the dwell time, t, i.e., the time spent by the projectile in the foil. In this work we consider only the long-dwell-time region t > 2 × 10^?15s. We study the variation of R_α = I^molec/I^atom (I^molec and I^atom are the Ly-α intensities per incident deuteron (proton) observed with molecular and atomic projectiles of the same velocity, respectively) with the projectile energy per nucleon ($\text{E}\text{M}$) and the thickness (T) of the foil. For a foil of given thickness, R_α increases with $\text{E}\text{M>}$ and reaches a saturation value R_∞ which decreases when T increases. These results, in agreement with our previous measurements using hydrogen projectiles, indicate that t is not the only parameter relevant to molecular effects. Comparisons are reported between $\text{R>}{}_{\mathrm{\alpha }}\text{(E}\text{M>}$) values obtained (a) with H₂⁺ and D₂⁺ projectiles and (b) with D₂⁺ and D₃⁺ projectiles, using foils of various given thicknesses. Ratios $\text{R}{}_{\mathrm{\beta }}\text{(E}\text{M}$) and $\text{R}{}_{\mathrm{\gamma }}\text{(E}\text{M}$) are also measured using Ly-β and Ly-γ radiations and compared to $\text{R}{}_{\mathrm{\alpha }}\text{(E}\text{M}$) values. An interpretation for some of our results is proposed.     

Cross sections for K-shell ionization by 1H, 2H, 3He,and 4He ion impact

Cross section for K-shell ionization derived from experimental measurements with the light ions ¹H, ²H, ³He, and ⁴He are tabulated according to projectile energy and target atomic number.