  We propose two types of neutron-$\gamma_1$-$\gamma_2$ triple coincidence
detectors (not constructed) to chase gamma transitions to produce p-nuclei
following the neutron emission in the $(\gamma, n)$ reaction. Neutrons are
detected with 24 $^3$He counters embedded in a polyethylene moderator in Type I
detector and with 6 liquid scintillation detectors in Type II detector,
respectively. $\gamma$ rays are detected with two high-purity germanium
detectors and four LaBr$_3$(Ce) detectors. The detector which is referred to as
p-process chaser detector is used to search for mediating states in $^{180}$Ta
through which the isomeric and ground states in $^{180}$Ta are thermalized in
the p-process. A search is made for both resonant states and unresolved states
in high nuclear-level-density domain.
