For the first time the results of on-line testing of metal Hall sensors based on nano-thickness (50 ÷ 70 nm) gold films, which was conducted under irradiation by high-energy neutrons up to the high fluences of 1.51020 ncm-2, are presented. The testing has been carried out in the IBR-2 pulsed fast reactor in the neutron flux with the intensity of 21013 ncm-2s-1 at the Joint Institute for Nuclear Research. The energy spectrum of the neutrons in the flux was very close to that expected for the ex-vessel locations in the ITER experimental reactor. The magnetic-field sensitivity of the gold sensors was stable within the whole fluence range under research. Also sensitivity values at the start and at the end of irradiation session were equal within the measurement error (< 1%). The results obtained make it possible to recom-mend gold sensors for magnetic diagnostics in the new generation fusion reactors of DEMO scale.

The pseudomorphic AlGaAs/InGaAs/AlGaAs heterostructure δ-doped with silicon on both sides and used for fabrication of high-power transistors is optimized to obtain a high concentration n _s and mobility of two-dimensional electron gas in the quantum well (n _s ≈ 3 × 10¹² cm⁻²). Electrical and structural characteristics of the samples grown by molecular-beam epitaxy with various doping levels are studied. It is shown that the mobility and concentration of electrons varies as doping level is increased and the subbands of dimensional quantization are sequentially filled. In order to analyze the distribution of electrons in subbands of the heterostructure, the Shubnikov-de Haas oscillations at the liquid helium temperature were studied. The quality of the heterostructure layers was assessed using the method of X-ray diffraction. The data of photoluminescence spectroscopy are in good agreement with the results of calculations of the band structure.

The work presents the results of experimental investigation into the effect of neutron irradiation on thin-film magnetic field Hall sensors. It is shown that sensors based on InSb/i-GaAs heterostructures are promising for application under radiation conditions in thermonuclear reactor magnetic diagnostics systems. At the same time, the presence of buffer layers in InAs/i-GaAs heterostructures makes this material unfit for application under neutron flux conditions.