Investigation of space-charge effects in gaseous tritium as a source of distortions of the beta spectrum observed in the Troitsk neutrino-mass experiment

Results of searches for effects of space-charge accumulation in the gaseous tritium source in the Troitsk neutrino-mass experiment are presented. The broadening and the shift of the L3 line of conversion electrons in a 83m Kr gaseous source circulating together with tritium was investigated. The attained limit on the magnitude of fluctuations of the space-charge potential makes it possible to set a limit on the negative neutrino mass squared in the Troitsk neutrino-mass experiment (−0.8 < Δ m ν 2 ≤ 0 eV2), a spurious effect associated with this potential. A statistically reliable shift of the position of the L3 line is discovered. This indicates that processes of of space-charge accumulation do indeed proceed in the source at a level that is significant for the future experiment Katrin.