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NICA is a new accelerator collider complex under construction at JINR. The facility is aimed at providing collider experiments with heavy ions up to Uranium in a center of mass energy range from 4 to 11 GeV/u and an average luminosity up to 1027 cm -2 s-1. The collisions of polarized deuterons are also foreseen. The facility includes two injector chains, a new superconducting booster synchrotron, the existing 6 AGeV superconducting synchrotron Nuclotron, and a new superconducting collider consisting of two rings, each of about 500 m in circumference. The booster synchrotron and the NICA collider are based on an iron-dominated “window frame”-type magnet with a hollow superconductor winding analogous to the Nuclotron magnet. The status of the development of the full size model magnets for the booster synchrotron as well as for the NICA collider is presented. The test results of model magnets are discussed. The status of the creation of a facility for serial tests of superconducting magnets for the NICA project is described.

In the Laboratory of High Energies at the Joint Institute for Nuclear Research, as part of the NICA-MPD [1] project, tests of two prototypes of HTSC current leads prepared at ASIPP institute (Hefei, China) have been performed [2, 3] to measure electric and heat parameters and to search for structural and physical drawbacks. Based on the experimental results, necessary changes are made in the structure of HTSC current leads of the testing stand for the magnetic element testing of the NICA accelerating complex and its basic setups: the Nuclotron, Booster, and Collider.

New accurate data of the neutron-proton spin-dependent total-cross-section difference ΔσL(np) at the neutron-beam kinetic energies 1.39, 1.69, 1.89, and 1.99 GeV are presented. In general, these data complete the measurements of energy dependence of ΔσL(np) over the Dubna Synchrophasotron energy region. Measurements were carried out at the Synchrophasotron of the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research. The quasi-monochromatic neutron beam was produced by breakup of extracted polarized deuterons. The deuteron (and hence neutron) polarization direction was flipped every accelerator burst. The initial transverse (with respect to beam momentum) neutron polarization was changed to a longitudinal one and longitudinally polarized neutrons were transmitted through the large proton longitudinally polarized target. The target polarization direction was inverted after one to two days of measurements. Four different combinations of the beam and target parallel and antiparallel polarization directions, both oriented along the neutron-beam momentum, were used at each energy. A fast decrease in −ΔσL(np) with increasing energy above 1.1 GeV and a structure in the energy dependence around 1.8 GeV, first observed from our previous data, seem to be well revealed. The new results are also compared with model predictions and with phase-shift analysis fits. The ΔσL quantities for isosinglet state I = 0, deduced from the measured ΔσL(np) values and known ΔσL(pp) data, are also given. The results of the measurements of unpolarized total cross sections σ0tot(np) at 1.3, 1.4, and 1.5 GeV and σ0tot(nC) at 1.4 and 1.5 GeV are presented as well. These data were obtained using the same apparatus and high-intensity unpolarized deuteron beams extracted either from the Synchrophasotron or from the Nuclotron.

New accurate results of the neutron-proton spin-dependent total cross section difference $\Delta\sigma_{\mathrm L}(np)$ 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 $\Delta\sigma_{\mathrm L}(np)$ with increasing energy above 1.1 GeV was confirmed. The structure in the $\Delta\sigma_{\mathrm L}(np)$ 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 $\Delta\sigma_{\mathrm L}$ quantities for isosinglet state I = 0, deduced from the measured $\Delta\sigma_{\mathrm L}(np)$ values and the known $\Delta\sigma_{\mathrm L}(pp)$ data, are also given. The results were completed by the measurements of unpolarized total cross sections $\sigma_{0\mathrm{tot}}(np)$ at 1.3, 1.4 and 1.5 GeV and $\sigma_{0\mathrm{tot}}(n$ C) 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.

Preliminary results of the ΔσL(np) at 1.4, 1.7, 1.9 and 2.0 GeV are presented. They were obtained during the two data-taking runs at the JINR Dubna Synchrophasotron in 2001 and complete the existing data above 1.1 GeV. The data analysis is in progress. The aim of the present studies is to determine the imaginary and real parts of the np spin-dependent forward scattering amplitudes over this energy range.

An essential part of the DiMuon Arm Spectrometer of the ALICE experiment is a conventional Dipole Magnet of about 890 tons which provides the bending power to measure the momenta of muons. The JINR engineering design of the Dipole Magnet, technical characteristics and description of the proposed manufacturing procedure are presented. The proposed Coil fabrication technique is based on winding of flat pancakes, which are subsequently bent on cylindrical mandrels. The pancakes are then stacked and cured with prepreg insulation. The method is demonstrated on hand of the prototype II, which consists of a pancake made with full-size aluminium conductor. Some details of electromagnetic and mechanical calculations are described. The results of measuring of mechanical and electrical characteristics of materials related to the coil composite structure are discussed.

New data on the spin-dependent np observables measured with quasi-monochromatic polarized neutron beam in the energy region from 1.2 to 3.7 GeV are presented. Further measurements of np scattering observables using the JINR LHE polarization facility (longitudinal and transverse polarized neutron beams and a polarized proton target) are discussed. The aim of these studies is to determine the imaginary and real parts of the forward scattering amplitudes for np and for isospin I=0 systems above 1.1 GeV.

New results of the neutron-proton spin-dependent total cross section difference $\Delta\sigma_L(np)$ at the neutron beam kinetic energies 1.59, 1.79 and 2.20 GeV are presented. Measurements were performed at the Synchrophasotron of the Laboratory of High Energies of the Joint Institute for Nuclear Research in Dubna. A quasi-monochromatic neutron beam was produced by break-up of extracted polarized deuterons. Neutrons were transmitted through a large polarized proton target. Measurements were performed either with a parallel or an antiparallel beam and target polarizations, both oriented along the beam momentum. The results at the two higher energies were measured with two opposite beam and target polarization directions. Only one target polarization direction was available at 1.59 GeV. The present measurements agree well with existing data. A fast decrease of the $-\Delta\sigma_L(np)$ values with increasing energy above 1.1 GeV was confirmed. The new results are also compared with model predictions and with phase shift analysis fits. The $\Delta\sigma_L$ quantities for isosinglet state I=0, deduced from the measured $\Delta\sigma_L(np)$ values and known $\Delta\sigma_L(pp)$ data, are given.

The superconducting accelerator Nuclotron was put into operation at JINR, Dubna. The accelerator contains 112 multipole correction windings. Each four of them are assembled as a magnet block with an inner diameter of 132 mm. The winding has one or two layers from NbTi multifilament conductor. The windings are impregnated with epoxy resin compound and glued on the tube coil with two-phase helium forced at 4.5 K. Each magnet has 100 A current leads without helium gas cooling. This very much simplifies the system of helium gas collection at the accelerator. All the magnets were tested and installed in the accelerator.

A hydrodynamic model of quasistreamer breakdown based on the system of equations of magnetohydrodynamics is studied. A third-order linear partial differential equation is obtained for the density disturbance of the plasma neutral component. Cauchy problems for this equation with localized and non-localized disturbances are solved by asymptotic methods (Ludwig's method and the WKB method). In the disturbed domain, anisotropic generation of three modes (one entropy and two acoustic modes) occurs. The short-term solutions obtained give a picture of the development of instability, in satisfactory agreement with experimental data. The absolute instability of the homogeneous plasma of non-selfsustained and selfsustained gas discharge is proved.