How to measure relative light intensity (and ideally duration) of a xenon flashes, cheaply
Your LDR is far too slow . Xenon flashtubes put out very short pulses .A setup that I did a DCDC convertor for gave me 100 microsec light pulses .The photo transistor will work at a pinch ,photo diode would be better ,I actually used phototransistor and a transimpedence amplifier using two BC547 transistors .Hopefuly this is within your frugal budget.