Does it help ?https://electronics.stackexchange.com/questions/229414/photodiode-circuit-for-measuring-light-intensity
Probably not, because the dude who answered it has drawn the diode the wrong way round,assuming you want a positive voltage on the output of the opamp.Leo..
the SCR acts as a type of latch - holding the input in the triggered state
Projects like this have been done before.Google "ballistic chronograph site:arduino.cc".Leo..
substituting a PT for a PD and how any given circuit may need to change to accommodate that
can I simply replace the PT with a reverse bias PD?