if i recall correctly, total capacitance is around 120 microfarad, it is a capacitor bank, the caps must be pulse-rated, and 45 kV is on the low side of charge. if you’re sketching out plans for future, you’ll want up to 75 kV rated caps. the total current per pulse may reach 1 million amps for a microsecond or so, and rise time needs to be 25 ns or less.
also, the caps are mounted around a circle, onto a flat plate, with anode in the centre, to minimize parasitic inductance.
25 ns rise time corresponds to a max frequency component of 20 MHz.