Abstract: By means of varying fish gelat in-AgBr ratio in a double-jet precipitation,nano-sized AgBr/I emulsion particles(average diameter of 13 nm)14 nm)were prepared and observed by TEM.It was discovered that the average size(d)of the AgBr/I nanoparticles almost unchanged but its size distribution coefficient(|±σ|/d)changed obviously at different fish gelatin-AgBr ratio.Increasing fish gelatin-AgBr ratio in a region from 0.31 g/mmole to 0.62 g/mmole,size distribution coefficient decreased from 19% down to 8.2%.By microwave photoconductivity measurement,two decay components of photoelect rons of nano-sized emulsion particles,initial fast decay and following slow decay,were showed and both components obey the kinetics of first order,which is similar to the situation observed in a cubic emulsion grain with an edge length of 0.6 μm.However,photoelectron lifetimes of nano-sized emulsion particles were shorter than that of the later.

Key words: silver iodobromide emulsion, nano-sized particles, fish gelatin-AgBr ratio, photoelectron decay