arXiv subjects
Publications and source records attributed to N. Z. Akopov.
We suggest fast algorithm for the matrix generator of pseudorandom numbers based on Kolmogorov-Anosov K systems which has been proposed earlier. This algorithm reduces $N^{2}$ operation of the matrix generator to $NlnN$ and essentially reduces the generation time. It also clarifies the algebraic structure of this type of K system generators.
We propose extended version of stationary string model to describe the nuclear attenuation. This model takes into account flavour content of particles and allows to include into consideration all hadrons created from string. The predictions of the model are compared with experimental results obtained by HERMES collaboration (DESY) on different nuclei (N and Kr).
An asynchronous accelerator is described, in which the principle of its operation permits the active longitudinal bunch compression of accelerated proton beams, to overcome the space charge limitation effects of intense bunches. It is shown that accelerated bunches from an RFQ linac can be adapted for Asynchronac injection for a multiple of choices in the acceleration frequencies of the RFQ and the Asynchronac. The offered new type of accelerator system is especially suitable to accelerate proton beams for up to 100MeV energy and hundreds of mA average current.
The possibility to convert the photon beam linear polarization into circular one at photon energies of hundreds GeV with the use of crystals is considered. The energy and orientation dependencies of refractive indexes are investigated in case of diamond, silicon and germanium crystal targets. To maximize the values for figure of merit, the corresponding crystal optimal orientation angles and thickness are found. The degree of circular polarization and intensity of photon beam are estimated and possibility of experimental realization is discussed.
The concept of large-radius multistage coaxial cyclotrons having separated orbits is described, to generate proton beams of 120-2000 MeV energy at tens of GW pulsed and hundreds of MW in continuous beam power operation. Accelerated beam losses must be less than 0.1 W/m for the intercepted average beam power linear density. The concept is inherently configured to actively compensate the longitudinal and transverse space charge expansion in beam bunches. These are based on (1) actively varying the bunch acceleration equilibrium phase while maintaining isochronism, independently for each cyclotron turns; (2) independently changing the acceleration voltage for each turn together with orbit corrections that preserve isochronism; (3) independently changing the transverse betatron oscillation tune shift, to assure non-resonant operation. Also, (4) sextupole lenses are included to compensate for chromaticity effects. Moreover, the concept is based on optimum uses of practical successful results so far achieved in beam acceleration and storage techniques. This accelerator can be used to deliver a pulsed intense source of neutrons without the use of storage rings, and to drive the different transmutation technologies. As an example of such a cyclotron system, we describe our approach of accelerating single-bunch proton beams at up to 1 GeV energy, with pulsed beam power of 80 GW and bunch duration of 2 ns. The exemplar cyclotron accelerator system is configured to be located in the shielded structure of the 6-GeV Yerevan Electron Synchrotron. The cost of such a cyclotron system is estimated to be approximately 40,000,000 US dollars, if implemented in Armenia at substantially reduced labor costs.
We analyze the structure of the periodic trajectories of the matrix generator of pseudorandom numbers which has been proposed earlier. The structure of the periodic trajectories becomes more transparent when the rational sublattice coincides with the Galois field $GF[p]$. We are able to compute the period of the trajectories as a function of $p$ and the dimension of the matrix $d$.