The electronic states of flat thin quantum rings of rectangular cross section whose thickness h, inner radius R_in and outer R_ex are related by the relations ; in are considered; hereinafter we will call them “quantum shims”. It is found that this type of narrow-gap heterostructures in a wide-gap matrix can become basic elements for spintronic systems. Their spectrum in an external magnetic field can be reduced to a single stable level, all quantum numbers of which (spin including) are controlled by the external field. This is proved both by numerical calculations and approximate analytical estimates, clarifying the mechanism of formation of such a state. Because of the conservation of an undamped quantum current and the associated magnetic moment, these states are more stable than in ideal quantum dots with a similar spectrum. The variants of changing the spin state of the electron localized on the puck by a longitudinal magnetic field are considered

Combined neutron therapy using a scanning neutron beam, proposed by the author, for the treatment of small superficial tumors, with controlled surface irradiation, a slow neutron beam, and the simultaneous use of plasmonic gold nanopreparations. The chemical stability and simple technology of gold nanoparticle (NP) synthesis methods facilitate their application in various fields of biomedicine, such as in vitro diagnostics, targeted drug delivery, and photothermal plasmon therapy. When combined with irradiation directed at the tumor surface with a slow neutron beam, gold NPs can be actively used as a dose-enhancing agent during neutron beam scanning of small superficial tumors of the resistive type. At the Pakhra electron accelerator, a secondary photon beam with an energy of 60 MeV was generated at an energy of 500 MeV. This beam was converted into a beam of moderated neutrons using a compact neutron source (CNS) and amplified by a device called a CNS amplifier (CA).

This article describes a technology for irradiating a tumor surface with a scanning beam of moderated neutrons in a combined mode, simultaneously irradiating the tumor with plasmonic gold nanoparticles (NPs). When irradiated with a femtosecond laser, the NPs reaching the tumor surface resonate and heat the tumor cells until they are destroyed. The beam of moderated epithermal neutrons is produced using a compact combined neutron source (CNS). The design and characteristics of the output beams of the KINK system were obtained through simulation using Geant 4. This article describes the configuration of the KINK system using a photon beam and the design of the KU neutron amplifier for tumor surface irradiation.