  Two-particle Hanbury-Brown-Twiss (HBT) interferometry is an important probe
for understanding the space-time structure of particle emission sources in high
energy heavy ion collisions. We present the comparative studies of HBT radii in
Pb+Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 17.3 GeV with Au+Au collisions at
$\sqrt{s_{\rm{NN}}}$ = 19.6 GeV. To further our understanding for this specific
energy regime we also compare the HBT radii for Au+Au collisions at
$\sqrt{s_{\rm{NN}}}$ = 19.6 GeV with Cu+Cu collisions at $\sqrt{s_{\rm{NN}}}$ =
22.4 GeV. We have found interesting similarity in the $R_{\rm out}/R_{\rm
side}$ ratio with $m_{\rm T}$ across the collision systems while comparing the
data for this specific energy zone which is interesting as it acts as a bridge
from SPS energy regime to the RHIC energy domain.
