Reducing the effect of external magnetic fields on the operation of a gas-filled neutron tube

The results of studies of the operating modes of ion Penning sources in the composition of small-sized gas-filled neutron tubes under the influence of external magnetic fields arising during the operation of logging equipment due to the intrinsic magnetization of casing strings are presented. According to the research results, it is shown that the greatest negative effect on the operation of neutron generators is exerted by a transversely directed external magnetic field. Based on the data obtained, options for constructing a shielded magnetic neutron tube system are proposed, taking into account the design features of the generator elements and the robust housing of the well geophysical research equipment. Measurements of the pressure dependences of the amplitude and delay of the pulse for shielded Penning ion sources have confirmed their effectiveness in improving the stability of neutron generators.