The simple method of modeling of tunnel diode (TD) oscillators’ work is described, and may be applied also to the other types of negative-differential conductance oscillators. In particular, the calculation of the harmonic oscillation amplitude is performed by the energy balance method, based on TD measured the current–voltage characteristic’ (I–V curve), using only one fitting parameter—the tunnel diode’s measured bias at which oscillations are quenched by means of which the oscillator’s effective total losses are determined also. The formula for calculation of the TD generator’s frequency is derived; it agrees with experiment and permits determination of its dependence on the radiotechnical scheme’s elements and TD I–V curve’s shape. The results of the calculation in comparison with the experiment are reported for the oscillators of various constructions operating at different conditions. For this, more attention is given to the constructive solutions applied in the low temperature experiments. Examples of the TD oscillators’ use in cryogenic techniques as well as in the superconducting detectors of particles and radiation are presented. The oscillators described generate, under the certain conditions, low-amplitude (<40 mV) sinusoidal signals with a highly stable frequency (not worse than ΔF/F=10−9/min at liquid-helium temperatures) and low intensity of higher harmonics in the soft mode. The power released is less than 10 μW and the measuring rf magnetic field’s amplitude at a sample, placed inside or near the oscillator coil, is less than 1 mOe. Using designed facilities we have already detected normal-to-superconducting phase transitions of tin grains with diameters of about 2 μm and phase transitions in micrometer thick and 20 μm2 high-Tc superconducting films.

Some aspects of high-T c superconductors (HTSC) electrophysical properties, which could be successfully applied to the detection of particles and radiation are discussed. The possibilities and the perspectives of the creation of completely new type detectors of elementary particles and ionizing radiation, based on HTSC materials, are considered. At this, the use of the unusual open-flat measuring (pick-up) coils made of, in particular, the HTSC materials, as a detecting element in known tunnel diode oscillator technique it seems of considerable promise and may find also a number of other applications in different areas of science and technology. The results of the HTSC thin-film structures real use for the detection of the visible and infrared spectrum radiations as well as constant magnetic fields and also direct currents passing through the HTSC film structures are presented. Three designs of these detectors are proposed suitable for various applications. The achieved up-to-date sensitivity is about 10-11 Wt/cm2/Hz-1/2 for the 0.63 μm and 0.8 μm wavelength radiations, about 0.1 mOe/cm2/Hz-1/2 for the constant magnetic fields and about 0.1 μA/cm2/Hz-1/2 for the direct currents passing through the HTSC thin-film structures. Capabilities of new detectors are evaluated and possible directions of further essential improvement of their parameters are also suggested.

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