Resolving duration and sequence of Na and continuum flashes during MBSL with time-correlated single photon counting
Time-correlated single photon counting (TCSPC) was used for the first time for resolving a duration and a sequence of the flashes of Na and continuum during MBSL from argon gas saturated aqueous NaCl and SDS solutions. It was found that a bubble giving both kinds of the flashes emits them simultaneously with a negligible delay of about 0.5 ns for Na flash. The duration of Na flash was defined as 4.6 ns, 7.5 ns, 11.2 ns for 5 M NaCl, 0.5 M NaCl, 5 mM SDS solutions, respectively. The duration of continuum flash was varying as 1.6-2.4 ns for all investigated solutions. To explain relatively large duration of Na flash, the scheme of evolution of presumable Na-emission zones is proposed based on the existence of an optimal temperature for Na emission.