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[en] A mathematical model of radiative heat exchange in the throats of wide-necked helium cryostats is analyzed. A comparison of the numerical results with known calculated and experimental data shows their good agreement

[en] Developed, produced and successfully operated is the cryogenic system with control in the temperature range from 4.2 to 270 K for investigation of inelastic neutron scattering in magnetic field up to 2.3 T. It consists of a crystal with a built-in superconducting solenoid, current source and electron regulator of temperature. Cylindrical specimens with 10-40 mm diameter with working part height of 50 mm are placed in the operation chamber vertically. 4.2 K temperature is provided by filling up of operation chamber with liquid helium, and in the interval from 5 to 270 K - by gas blowing with heating at constant waste and is stabilized by two-circuit temperature regulator. Instability of the established value of temperature in the range of 5-70 K is not more than +-0.1 K and in the 70-270 K range - not more than +-0.2 K. Magnetic field is directed along the specimen axis, irradiation with a hotizontal beam of neutrons is carried out in span of angle up to 150 deg. Control system is stable in the whole range of temperatures without rebuilding of regulator coefficients. The crystal scheme and functional scheme of the regulator are presented

[en] In the process of regulation and stabilization of liquid helium temperature at the initial stage of pressure increase the effect of advanced temperature increase, indicated by a carcass semiconductor thermometer, and its subsequent jump to the value corresponding to the temperature of liquid at the given moment is revealed. It is shown that irregular peculiarities in the indices of the carcass thermometers do not reflect the actual character of liquid temperature change, but are the consequence of processes taking place on their surfaces. A supposition is made that the peculiarities are determined by mutual effect of heat, released by measurement current in the thermometer, and the process of collapse of gas bubbles adhering to its surface

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