The HEBT channel is designed for transportation of 4 MeV/u energy ion beams with Z/A = 1/4–1/8 from linac to stripping target to prepare the beam for injection into the booster. The channel consists of magnetic quadrupole lenses providing transverse focusing of the beam and the debuncher to reduce the particles momentum spread to ±0.3

A new NICA collider lattice with the symmetric arrangement of triplets at the interaction points and a shifted working point (Qx,y ∼ 9.1) is proposed and calculated. This lattice involves two rings (ring A and ring B) with a superperiodicity of 2 and different optics. It is shown that, while maintaining the nominal beta function at the interaction points (βx,y= 0.35 m) with allowance for all perturbing factors, the new lattice allows DA ∼ 75 mm to be obtained in both rings, which is considerably larger than the collider chamber acceptance (ACC = 40 mm mrad).

A study of the NICA collider dynamical aperture (DA) using the MADX code has shown that, in the chosen working point (Qx,Qy ∼ 9,43), the DA sharply decreases when taking into account the fringe fields of the quadrupole lenses and dipole magnets. An analytical theory is developed to calculating the strength of resonances generated by the fringe fields of the quadrupole lenses in a circular machine. It is shown that the formulae derived for these parameters have a general character and do not depend on the lens design. The codes for a numerical calculation of the anharmonicity coefficients and resonance strength in the NICA collider are written. The method is developed to estimate the resonance strength by using the numerical simulation of the trajectories with the help of the MADX code. For the NICA collider structure, the results of the analytical calculation of the resonance strength for a chosen resonance coincide with the results obtained using the MADX code with a satisfactory accuracy.

The dependence of the dynamic aperture in the NICA collider on the number of turns has been calculated by MAD-X tracking code with the two independent algorithms: a program of symplectic tracking PTC (Polymorphic technology Tracking Code) and a program of the thin-lenses tracking method. The results of the numerical integration of particle motion forecast the asymptotic dynamic aperture and the possible losses of particles in the collider.

We report the results of a study into the feasibility of conducting the ELISE and EXL experiments on collisions of nuclei of radioactive fragments with electrons at the Institute for Theoretical and Experimental Physics (ITEP). A scheme for uranium ion acceleration in the ITEP accelerator complex is chosen, and it is shown that uranium ions may be accelerated with an intensity of ∼1 × 1011 ions/s as soon as the complex is modified and a new injector is constructed. The basic parameters of the modified complex are given, and a layout diagram indicating the positions of the target that serves to produce radioactive fragments, the separator, and the storage rings (CR, RESR, NESR, and ER) at the ITEP site is presented.

An algorithm for modeling the intra-beam scattering of particles in accelerator and storage rings was developed. It was obtained by solving the Fokker–Planck equation approximately in the space of invariants. The algorithm was used as a basis for devising a program for numerical modeling which is included as an individual module in the MOCAC (Monte Carlo Code) computational program. The program was checked and used to estimate the effects of intra-beam scattering of particles in the SIS100 synchrotron (FAIR, Germany).

In high-current ion rings, coherent motion of the electrons in the electron cooler should be considered as transverse drift in crossed fields: space-charge field of the ion beam and longitudinal magnetic field in the cooler. Taking this effect into account two-dimensional (4×4) martix of the ion coherent motion in the cooler has been derived. The limiting value of electron density in the cooler has been found by numerical claculation of the matrix determinant. It is shown that in a frame of this model limitation of the electron current is practically absent.

Fully stripped heavy ion beam of a nearly relativistic energy and a super high intensity is supposed to be accumulated in the storage ring of ITEP-TWAC Facility that is under construction at ITEP on the base of existing accelerators. Nonliouvillean multiturn injection technique is elaborated to store in the accumulator ring as much as one thousand batches, which are accelerated in the booster synchrotron with acceleration cycle frequency of 1 Hz. Computer simulation of the beam accumulation process is done with taking into account effects of intrabeam scattering and interaction with stripping foil: ionization energy loss, multiple Coulomb scattering and electron capture. Evolution of the 5-D phase space volume of the accumulating beam is calculated as a function of injection batch number, accumulation time, stripping foil thickness, foil matter and other multiturn injection system parameters. Results of simulation are presented and discussed.

In a synchrotron, slow extraction of a circulating beam when influenced by a nonlinear perturbation was analysed both analytically and by computer simulation. It was found that beam loss on the septum may be reduced twice and more if the particle distribution in the cross section of the kicker magnet is deformed with decapole perturbation of a sextupole magnetic field used for resonance excitation. A similar effect is observed for gradient resonance extraction with octupole perturbation. Results of simulation for the ITEP PS slow extraction system are presented.

The ITEP (Institute for Theoretical and Experimental Physics) 10-GeV proton synchrotron (U-10) is now being reconstructed into a proton and ion accelerator complex capable of accelerating ions of all atoms with various Z/A values. The first stage of the reconstruction includes construction of an ion injector as well as a beam transport line (from the new injector to the synchrotron), and modification of proton synchrotron systems necessary for ion acceleration. In particular, the synchrotron vacuum chamber and its pumping system must be modified to reach 10/sup -10/-torr vacuum instead of the present 10/sup -6/ torr. These modernizations are practically complete. In 1988, He/sup 2+/ ions were injected into the synchrotron and accelerated up to 4.3 GeV/A. In the current year, an effort will be made to accelerate some heavier ions obtained from the new injector. It is expected that light ions will be accelerated up to 4 GeV/A, and heavy ones (not fully stripped) up to 1 GeV/A.< >

A simple approximate formula is advanced for calculating the frequency shift of betatron oscillations which occurs for motion of particles in nonlinear magnetic fields of cyclic accelerators. The accuracy of the formula is estimated. For a certain specific distribution, the results of the approximate and exact numerical calculation are compared. The formula allows the properties of magnetic systems to be investigated and permits ways to be found for improving them.