[en] Differential cross sections of the elastic scattering of pions on ³He nuclei are measured at energies of 68, 98, 120, 135, 145, 156, 198, 208 MeV. The experiments are carried out in a high pressure helium streamer chamber. The data obtained are compared with calculations performed accordingly to the optical model. Estimates of the coupling constant of f²(π³He³H) are presented

[en] Photographs of electron tracks in a streamer chamber 22 cm in dia with a discharge gap of 7 cm, have been obtained, the chamber being filled with hydrogen at pressures from 200 torr to the atmospheric pressure. The inner volume of the chamber is separated from the electrodes with o.lass covers 1.2 cm thick. An exponental pulse with an onward front about 10 ns, the 1.5 mks time constant of a decay exponent and an amplitude to 280 kV has been supplied to the chamber from a high-voltage pulse generator. The chamber has been started up by electrons from a ⁹⁰Sr source. The minimum delay of the high-voltage pulse has been 0.4 mks. The chamber having been pumped out to the vacuum of 10^-2 torr, with an intermediate washing, additions are introduced into it. During the streamer chamber operation in the regime of self-shunted discharge (use of a long high-voltage pulse) one can obtain satisfactory tracks at a reduced gas pressure in the presence of small amounts of methane. The tracks can be seen at a pressure to 400 torr but at a higher pressure they disappear completely in the general luminescence of the whole gas volume. The discharge shape and, therefore, track localization in hydrogen, does not depend on the pulse duration, the pulse duration exceeding a few nanoseconds. This makes the operation in the self-shunted regime possible, that provides the maximum track brightness be obtained at a given amplitude of a high-voltage pulse. Additions of other gases to hydrogen increase significantly the track brightness and allow their photographs to be obtained at a hydrogen pressure up to 1 atm and an electrical field intensity to 27 kV/cm

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[en] Electron track brightness and localization are studied using three-component mixtures in a streamer chamber. The additives used are CH₄ (0.2-2%) and water vapour (0.005-0.3%). The experiments are carried out with a 180-mm-diam. and 60-mm-discharge gap glass chamber. The chamber is pumped out down to 2 x 10^-3 torr. The maximum high-voltage pulse amplitude has been 280 kV with a leading edge of about 10 ns and a pulse-decay time of 1.5 mcsec. The total instrumental pulse delay from the moment of pulse passage has been 0.4 mcsec. Pictures of electron tracks in a 32.5 kV/cm electric field are given. It has been found that there is good track localization only at pressures of 600-700 torr. The chamber storage time, 1 mcsec, allows one to work with large ionized particle fluxes, 10⁵ - 10⁶ C^-1. The size of the localized brightly shining part of the streamers along the adge does not exceed 2 mm. The optimum concentration of water vapour has turned out to be 0.05%

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