  The intensity interferometry is applied as a chronometer of the particle
emission of hydrogen isotopes from the intermediate velocity source formed in
$^{40}$Ar+$^{197}$Au reactions at 30 MeV/u. The dynamic emission order of
$\tau_{\rm p}>\tau_{\rm d}>\tau_{\rm t}$ is evidenced via the correlation
functions of nonidentical particle pairs. Assuming the similar source size, the
same emission order is inferred from the correlation functions of identical
particle pairs, where $\tau_{\rm p} \approx 100 {\rm ~fm/c}$ is extracted by
the fit of Koonin-Pratt equation to p-p correlation function. Transport model
simulations demonstrate that the dynamic emission order of light charged
particles depends on the stiffness of the nuclear symmetry energy.
