  Searches of new physics beyond the Standard Model (SM) performed at low
energy frontiers are complementary to experiments carried out at high energy
colliders. Among the methods for testing the SM and beyond at low energies are
the precision spectrum shape and correlation coefficient measurements in
nuclear and neutron beta decay. In order to study tiny effects in beta spectrum
shape, a special spectrometer was built. It consists of a 3D low pressure gas
tracker (drift chamber with hexagonal cells, signal readout at both wire ends)
and plastic scintillators for triggering data acquisition and registration of
the beta particle energy. The results of the characterization process indicate
the possibility of using such a gas tracker in a range of experiments with low
energy electrons where beta particle tracking with minimal kinematics
deterioration is beneficial. Application of this technique is also planned for
neutron decay correlation experiments. In the paper, the first application of
this tracker in a high-precision beta spectrum shape study is discussed. The
measurement technique, commissioning results, and the future outlook are
presented.
