The Definition of the Time-Space and Power Performances of the Ultrawideband Antennas

The definitions of the time-space, frequency−space and power characteristics of the ultrawideband antenna systems permitting to evaluate from unified positions the overall performance of different function videopulse radiotechnic systems are given.Даны определения пространственно-временным, пространственно-частотным и энергетическим характеристикам сверхширокополосных антенных систем, позволяющие оценивать с общей позиции общую эффективность видеоимпульсных радиотехнических систем различного назначения.Дано визначення просторово-часовим, просторово-частотним та енергетичним характеристикам надширокосмугових антенних систем, що дозволяють оцінювати з загальної позиції загальну ефективність відеоімпульсних радіотехнічних систем різного призначення

Experimental Constraints on the Ordinary Chondrite Shock Darkening Caused by Asteroid Collisions

Shock darkening is caused by two distinct mechanisms with characteristic pressure regions, which are separated by an interval where the darkening ceases. This implies a reduced amount of shock-darkened material produced during the asteroid collisions

Determination criterion far-field for recirculating and cylindrical antenna lattices

В статье рассмотрена возможность определения критерия дальней зоны (ДЗ) для кольцевой и цилиндрической антенных решеток по различным критериям, в частности по уровню боковых лепестков, по уменьшению крутизны пеленгационной характеристики, по уходу нуля пеленгационной характеристики, по ширине главного максимума диаграммы направленности (ДН), по изменению уровня главного максимума ДН.У статті розглядається можливість визначення далекої зони для кільцевої та циліндричної антен за різними критеріями.Possibility of the determination criterion far-field is considered in article for recirculating and cylindrical antennas on different requirements

The New 249^{249}No Isotope

International audienceIn the reaction of complete fusion of $^{48}$Ca-ions with a $^{204}$Pb target, a new α line, related to the decay of a new, previously unknown isotope ($^{249}$No), has been detected in an experiment carried out at the SHELS separator. The α decay energy (E$_{α}$ = 9129 keV) and the half-life (T$_{1/2}$ = 38.1 ± 2.5 ms) are measured using the GABRIELA detector array. The SF branching ratio was estimated (b$_{SF}$ ≤ 0.2%)

Structure of the prompt neutron multiplicity distribution in the spontaneous fission of 256Rf

An experimental study of 256Rf spontaneous fission following the fusion reaction of 50Ti+208Pb was performed using the velocity filter SHELS of the Flerov laboratory at JINR. The average number of neutrons of ν‾=4.30±0.17 and variance of σν2=3.2 from the prompt neutron multiplicity distribution were obtained. The alpha decay branching ratio of bα=0.003−0.003+0.005 and the half-life of T1/2=(6.7±0.2) ms of the isotope were determined. For the first time, our neutron detector system allowed us to extend investigation of the prompt neutron multiplicity study to the superheavy element region

Comparative Study of Spontaneous-Fission Characteristics of 252^{252}No and 254^{254}No Isotopes

International audienceSpontaneous fissions of the $^{252}$No and $^{254}$No nobelium isotopes have been studied in a series of experiments with the SHELS separator. These isotopes are produced by colliding a beam of $^{48}$Ca ions from the U-400 cyclotron with the $^{206}$Pb and $^{208}$Pb targets. The measured characteristics of the $^{252}$No and $^{254}$No spontaneous fissions include their half-lives, total kinetic energies of fission fragments, and prompt-neutron multiplicities. The average number of neutrons per $^{254}$No spontaneous-fission act is measured for the first time as 4.88 ± 0.53

The SFiNx Detector System

International audienceA new detector system for investigating the properties of spontaneous fission of short-lived transuranium nuclei has been created. This system consists of an assembly of double-sided silicon strip detectors surrounded by 116 proportional neutrons counters filled with $^{3}$He. The neutron registration efficiency is 54.7 ± 0.1%. The detector system is tested in an experiment investigating the characteristics of spontaneous fission of the $^{252}$No isotope. The experimental data on neutron yields are compared with previously published results. The average number of neutrons per fission act ($\bar {\nu }$ = 4.25 $\pm$ 0.09) and the multiplicity distribution of prompt neutrons are obtained. The true form of the neutron distribution is reconstructed via a statistical regularization