I did this a long time ago, which unfortunately I don't have schematics of, wait maybe I'll check, but I verified the photodiode response, using an LED (LEDs are quite fast, some MHz of modulation bandwidth) to be sure the flash was measured correctly. I also cross-verified it with a current transformer, or inductive probe of some sort.
Let's see here...
This was I think, inductive pickup of a xenon flashlamp discharge. Probe would've been a common 10x scope probe, tip to ground clip, and the loop held by the capacitor/lamp.
The induced EMF is generally the derivative of current, so, this implies a unipolar pulse on the order of 20us.
Another:
This might've been photodiode, or CT. Not sure if it was the same setup, or a different capacitor.
I think I had tried several parts, including an axial capacitor (looong pulse), snap-in type (amazingly short pulse, maybe the first image?), and film (in-oil, metal can, 20uF, actually rated for some current not just a motor-run cap, maybe the second image?).
Ah yeah, here's the schematic,
That type of photodiode I think is common in old remote-control receivers, the non-integrated kind? No idea of specs. It's black, so it doesn't respond much to visible light, but I got enough response from a red LED to correct the pulse, hence the RCs.
I remember also trying it with a high voltage cap and air spark, with pulses in the 50ns range. Don't remember if that was attributable to EMI from the spark, or actual optical output...
In any case, I did seem to confirm that conventional xenon simply doesn't switch faster than some microseconds. Which is indeed one of the problems Edgerton originally had. And air sparks were a solution, downside being the somewhat bluer color I think, not to mention harmful UV.
In any case, for the photodiode -- expect quite large photocurrents, even for very short pulses. Flashes are
intense! You won't need much transimpedance to see it, heck even a low impedance (biased photodiode direct-driving 50 ohms?) may be good enough!
Tim