Characterization of a hybrid ${it telescope}$ with gas transmission detector ($Delta$E) and a solid-state stop detector (E) has been fabricated for detection of low energy $alpha$ particles between 5 to 1 MeV. The detector is developed for utilization in the study of alpha excitation function in (p.$alpha$) reaction. The gas ionization chamber, operated in axial field mode, measures the differential energy loss ($Delta$E), while the residual energies are measured by silicon detector. Particle identification is realized by implementing the $Delta$E-E technique. The optimum sensitivity of the detector as a telescope has been studied down to the lowest energy value of 0.89 MeV $alpha$-particles with a suitable combination of electric field and pressure or E/p value in the ionization region.