No abstract available

[en] An optical method has been used to calibrate the thickness of thin carbon films used as charge-exchange targets in an electrostatic accelerator with ion charge exchange. Assuming that light attenuation in a carbon film exponentially depends on its thickness, it is possible to determine the ratio of thicknesses of two films by using the ratio of their transparences. If an optical silicon converter is used, the coefficient which relates the film thickness with its transparency is equal to (34+-2) μg/cm²

[en] To stabilize and measure the energy of accelerated ions in the EGP-8 electrostatic accelerator, use is made of a beam of neutral atoms produced during charge exchange of negative ions. Neutral atoms are then recharged into ions and their energy is measured with the help of an electrostatic analyzer. Used as a detector are crystals of CsJ(Tl) divided by a thin opaque baffle and connected by means of light guides with two photomultipliers. The detector serves also as a beam position monitor and its signal corrects the voltage of the accelerator high-voltage elctrode. The system has been tested in measuring (p, γ) resonances and (p, n) threshold reactions. The voltage stability and the beam energy nonuniformity constituted 4x10^-4, the main contribution into the beam energy nonuniformity being made by a solid charge-exchange target

[en] A polarimeter using a silicon detector as the analyser has been designed for measurements of proton polarization over a range of energies from 2.6 to 4.0 MeV. In this range the effective analyzing power varies smoothly between -0.2 and -0.7. The mean registration efficiency of the polarimeter is about 2.5x10^-6. (orig.)

[en] Inclusive spectra of protons emitted in the interaction of ³He ions with an energy of 4.9 GeV/nucleon with nuclei of C, Cu and Pb were measured. The analysis of these data as well as of those available on nucleus-nucleus interactions at other energies (0.8, 2.1 and 3.6 GeV/nucleon) and for other combinations of colliding nuclei (from ³He+C to Ar+Pb) has shown that in the target nucleus fragmentation domain the invariant cross section is described by a certain universal function if we go over into the appropriate moving frame. It is natural to interpret the latter as a real physical object, i.e. a moving source. This source turns out to be highly heated (the average energy being > or approx.90 MeV/nucleon), at the same time its inner properties (the excitation energy and distribution form) do not depend either on the collision energy or on the projectile-target combination. On the other hand, the source velocity and the number of nucleons involved in it are systematically dependent on the collision conditions. (orig.)

[en] Inclusive spectra of protons emitted in the interaction of ¹²C-projectiles at an energy of 3.6 GeV/nucleon and C, Cu, Sn and Pb target nuclei were measured. The analysis of the experimental data suggests that in all these interactions the main contribution to proton cross sections in the investigated kinematic region is due to emission from a moving source with a rapidity which differs greatly from the target nucleus rapidity, ysub(t), as well as from that of the effective fireball. The properties of this source such as the excitation energy depend only slightly on the combination of the colliding nuclei. (orig.)

[en] We have experimentally and numerically investigated a multiwavelength strontium vapour laser which simultaneously emits both in the IR spectrum range on the self-terminating transitions in strontium atoms and ions ($\mathrm{\lambda <!--\; ??\; -->}=6.456$ and $\sim <!--\; ???\; -->3\text{μ<!-- ?? -->}\text{m}$ for Sr I, and $\mathrm{\lambda <!--\; ??\; -->}\approx <!--\; ???\; -->1\text{μ<!-- ?? -->}\text{m}$ for Sr II) and in the visible range on the recombination transition in strontium ions ( $\mathrm{\lambda <!--\; ??\; -->}=0.4305\text{μ<!-- ?? -->}\text{m}$ for Sr II). A number of regularities in the behaviour of the output characteristics of lasing, which allow for a targeted search for optimal excitation conditions of the multiwavelength strontium vapour lasers, are established. (lasers, their applications and other topics in quantum electronics)

[en] New experimental results on the ratio R_dp of the quasi-elastic charge-exchange yield at the outgoing proton angle θ_p,Lab=0 for the nd→p(nn) reaction to the elastic np→pn charge-exchange yield are presented. The measurements were carried out at the Nuclotron of the Veksler and Baldin Laboratory of High Energies of the JINR (Dubna) at the neutron beam kinetic energies of 0.55, 0.8, 1.0, 1.2, 1.4, 1.8 and 2.0 GeV. The intense neutron beam with small momentum spread was produced by break-up of deuterons which were accelerated and extracted to the experimental hall. In both reactions mentioned above the outgoing protons with the momenta p_p approximately equal to the neutron beam momentum p_n,beam were detected in the directions close to the direction of incident neutrons, i.e. in the vicinity of the scattering angle θ_p,Lab=0 . Measured in the same data taking runs, the angular distributions of the charge-exchange reaction products were corrected for the well-known instrumental effects and averaged in the vicinity of the incident neutron beam direction. These corrected angular distributions for every of nd→p(nn) and np→pn charge-exchange processes were proportional to the differential cross-sections of the corresponding reactions. The data were accumulated by the Delta-Sigma set-up magnetic spectrometer with two sets of multiwire proportional chambers located upstream and downstream of the momentum analyzing magnet. Inelastic processes were considerably reduced by the additional detectors surrounding the hydrogen and deuterium targets. The time-of-flight system was applied to identify the detected particles. The new R_dp data are compared with the existing ones, which were obtained below 1 GeV, and with the calculations which were made using the phenomenological NN amplitude sets. (orig.)

[en] New accurate results of the neutron-proton spin-dependent total cross section difference Δσ_L(np) at the neutron beam kinetic energies 1.39, 1.69, 1.89 and 1.99 GeV are presented. Measurements were carried out in 2001 at the Synchrophasotron of the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research. A quasi-monochromatic neutron beam was produced by break-up of extracted polarized deuterons. The deuteron (and hence neutron) polarization direction was flipped every accelerator burst. The vertical neutron polarization direction was rotated onto the neutron beam direction and longitudinally (L) polarized neutrons were transmitted through a large proton L-polarized target. The target polarization vector was inverted after 1-2 days of measurements. The data were recorded for four different combinations of the beam and target parallel and antiparallel polarization directions at each energy. A fast decrease of Δσ_L(np) with increasing energy above 1.1 GeV was confirmed. The structure in the Δσ_L(np) energy dependence around 1.8 GeV, first observed from our previous data, seems to be well pronounced. The new results are also compared with model predictions and with phase shift analysis fits. The Δσ_L quantities for isosinglet state I=0, deduced from the measured Δσ_L(np) values and the known Δσ_L(pp) data, are also given. The results were completed by the measurements of unpolarized total cross sections σ_0tot(np) at 1.3, 1.4 and 1.5 GeV and σ_0tot(nC) at 1.4 and 1.5 GeV. These data were obtained using the same apparatus and high intensity unpolarized deuteron beams were extracted either from the Synchrophasotron, or from the Nuclotron. (orig.)