Iterative computing of transmittance of optical elements focusing at a predetermined area

A new modernization of the Gerchberg-Saxton (GS) iterative algorithm has been suggested with reference to the task of focusing a coherent monochromatic beam into a preset frequency-plane domain with a given intensity distribution.

The modernization proposed permits computation of the transmittance function, within a diffraction approximation, of the optical element focusing into a preset domain, with an error essentially less than that of the standard variant of the GS algorithm.     

Fluctuation of rare-earth atom magnetic moments in superconducting ceramics (Ho,Er)-Ba-Cu-O studied by μSR

Zero field muon spin relaxation measurements of the ceramic high-T_c superconductors HoBa₂Cu₃O_7-σ, O_c≃93 K) and ErBa₂Cu₃O_7-σ (T_c≃95 K) reveal the sharp difference between the behaviours of the muon spin relaxation rate at temperatures below 20K. This fact may be explained by assumption that the frequency of fluctuations of Er magnetic moments exceeds by far the fluctuation frequency of Ho in 1-2-3 compounds.     

Positive muon diffusion in helicoidally-ordered antiferromagnets

A method for measuring the time scale for positive muon diffusion in helicoidally ordered antiferromagnets is proposed. The experiment shows that the muon diffusion in dusprosium over the temperature interval 100–175 K is a tunneling process.     

Cosmic rays of energies in the range 103–105 TeV and higher

Over a period of more than 30 years, the knee in the spectrum of extensive air showers (EAS) generated by cosmic radiation has been explained in two ways: as a consequence of a cusp in the energy spectrum of primary cosmic rays or as a consequence of a change undergone by the process of multiparticle hadron production in the interactions of primary protons with nuclei of air atoms. Investigations at the Tien Shan EAS array confirm a change in the properties of showers generated by protons near the upper boundary of the atmosphere and evince the invariability of the energy spectrum of protons in the energy range 10³–10⁵ TeV.     

The μSR investigations on the phasotron at Dubna: The present and the future

After conversion of the LNP JINR phasotron new opportunities have been opened for μSR-research. A new round of investigations has begun since 1987. In this paper we present the summary of the results achieved and give some prospects for future investigations.