相对论离子与氦二聚体碰撞电离的理论研究

基于对称程函近似,从理论角度研究了相对论离子与氦二聚体碰撞双电离的直接碎裂通道：由入射离子与两个原子的作用造成的双电离。从不同的近似角度出发,建立了两个理论模型,第一个模型将氦二聚体的两个原子看做一个整体,而另外一个模型完全忽略了两个氦原子之间的相互作用。模型的数值计算结果表明,总截面与氦二聚体的空间取向有很强的依赖关系,当氦二聚体与入射离子束流平行时,总截面达到最大值,在垂直时为最小值。进一步研究发现,模型一的结果在氦二聚体核间距较小时更为合理,核间距较大时,模型二更为精确。     

发光玻璃在X射线实时成像系统中的应用

介绍了以铽（Ｔｂ）激活的高密度发光玻璃和光导纤维发光玻璃的特性。它应用在Ｘ射线实时成像系统中,可大大改善空间分辨能力。用它做的转换屏比一般晶粒状荧光物质做的厚得多,特别适合用于高能Ｘ射线实时成像系统     

Multiple ionization of atoms and the energy of recoil ions in collisions with fast,multiply charged ions

On the basis of the sudden perturbation approximation and the model of independent electrons, simple analytical expressions are obtained for the cross sections of multiple ionization of atoms and the average energies of recoil ions in collisions between atoms and fast, multiply charged ions in the range of parameters in which the Born approximation is inapplicable. An expression for the energy distribution function of recoil ions is also obtained.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 111–116, April, 1996.     

Cross sections for single and double ionization of atomic helium under impact by fast multiply charged ions

Expressions for the cross sections for single and double ionization of atomic helium in collisions with fast multiply charged ions are obtained in the collision parameter range υ ²≫Z≳υ, υ ₀<c, where Z and υ are, respectively, the ion charge and ion velocity, υ ₀ is the characteristic velocity of electrons in the atomic helium ground state, and c is the velocity of light. Zh. Tekh. Fiz. 68, 1–7 (March 1998)     

Negative hydrogen-ion neutralization in collisions with fast highly charged ions

The neutralization of negative hydrogen ions is considered for collisions with fast multicharged ions (including relativistic collision velocities) by means of an approach that gives a simple analytic expression for the neutralization cross section in the parameter region where the Born approximation is inapplicable. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 42, No. 1, pp. 87–95, January, 1999.     

Nonlinear bound-free pair creation in the strong electromagnetic fields of a heavy nucleus and an intense x-ray laser

We study e(-)e(+) pair creation in the collision of a heavy nucleus with an intense x-ray laser, where the produced e(-) is simultaneously captured into the K shell of the projectile nucleus. The parameters of the colliding system are chosen such that the absorption of at least two photons from the laser wave is required in order to surmount the energy threshold of the reaction. Considering this fundamental nonlinear strong-field process for the first time, we estimate the total production rate as well as the angular and energetic distributions of the emitted positrons. According to our results, the process of nonlinear bound-free pair creation could become observable by the aid of the upcoming x-ray laser facilities.     

Induced recombination and the possibility of amplifying radiation in a plasma

A study is made of induced photorecombination caused by collisions of electrons with ions (atoms) of a plasma in the presence of a strong electromagnetic field. A negative coefficient of absorption of the radiation is obtained for the recombination of an electron in the discrete state, with subsequent spontaneous radiation decay of the electron. If the autoionized state is present in the continuous spectrum of an atom, then taking photoabsorption into account means that for narrow electron distribution functions the absorption coefficient can be either positive or negative.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 34–38, August, 1987.     

Generation of currents in gases by fast, highly charged ions

It is shown that an exit asymmetry of the electrons and recoil ions formed during ionization of atoms in elementary collision events with fast, highly charged ions can give rise to macroscopic electron and recoil ion currents during the bombardment of a gaseous target by a beam of fast, highly charged ions. Zh. Tekh. Fiz. 68, 20–23 (September 1998)