I am measuring flourescence lifetimes with a picosecond pulse laser, using the LifeSpec II with an MCP detector. Instead of a single peak rapidly decaying, as would be expected, my IRF contains two peaks. I am suspecting some sort of reflection causing this. Does anyone get what I mean here? Could add a graph soon if that might help.
EDIT: I have realized this might not be an error, but I would still like to know why.