We regard the possibility of detecting the antineutrino flux producing by the $^{40}$K placing inside the Earth. Thermal flux of the Earth could be better understood with observing such a flux. Lower and upper limitations on the $^{40}$K antineutrino flux are presented.
Positron spectrum from inverse beta decay reaction on proton was measured in 1988-1990 as a result of neutrino exploration experiment. The measured spectrum has the largest statistics and lowest energy threshold between other neutrino experiments mad
e that time at nuclear reactors. On base of the positron spectrum the standard antineutrino spectrum for typical reactor fuel composition was restored. In presented analysis the partial spectra forming this standard spectrum were extracted using specific method. They could be used for neutrino experiments data analysis made at any fuel composition of reactor core.
